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International Poplar Commission

25th Session, Berlin, Germany

Activities Related to Poplar and Willow Cultivation and Utilization 2012-2015

National Poplar Commission of BELGIUM

Period: 2012 through 2015 I. POLICY AND LEGAL FRAMEWORK Belgium is regionalised for topics related to agriculture and forestry with two significant regions for the poplar and willow stands: Wallonia and Flanders. The administrative and politic differences of these Regions have obliged to work separately. The input from two Regional Commissions in Belgium were integrated for this national report. When regional differences are necessary to be presented in this summary of the last four years activities and results, the chapter is separated specifying the Regions particularities. For each “article” the mentioned authors and institution to which they belong to indicate the Region in which the result is achieved. I.1 Flemish Region

Joris Van Acker

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Joris.VanAcker@UGent.be

For the reporting 4 years ago the Flemish Regional Poplar commission still acted under the coordination of Jos Van Slycken. He passed away 12 July 2012. Without his guidance the institutional continuation of this commission was hardly supported. Several research teams working on the different thematics both in institutes and at universities continued their work and interacted without a structural regional or national framework over the last 4 years. Only recently an initiative was taken to establish a Flemish Poplar Committee primarily as ad hoc group bringing together the different stakeholders in Flanders. A successful meeting on May 26th 2016 in Brussels at the European Forestry House emphasizing the still strong will to interact, collaborate and seek opportunities for the future of poplar and willow in Flanders. A large group was involved in the set-up of this meeting and those effectively participating contributed intensively to the discussion on the future of poplar in Flanders and the options to continue selection and breeding at INBO. This report is to some extent also reflection of the

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contributions of different stakeholders both to this Flemish Poplar committee and as dissemination towards the international Poplar commission. The following people (in alphabetical order) agreed to take part in the Flemish Poplar Committee (Vlaams Populieren Comité – VPC) and to have a network meeting at least once each year seeking increased interaction and support for poplar cultivation and related ecosystem services. Prof. BOERJAN Wout (VIB) Mr. CALUWAERTS Willy (Company CALUWAERTS) Prof. CEULEMANS Reinhart (UA) Mr. CLAES Dries (Bosgroep Dijle-Geteland) Mr. COUSSEMENT Jan (SYLVA) Mr. DE BOCK Marc (De Bock Marc Hout-Bois bvba) Mr. DE BOEVER Lieven (WOOD.BE) Mr. DE GROOT Maurits (APB) Mr. DE KEERSMAEKER Luc (INBO) Mr. DE MEERSMAN François (FEDEMAR) Mrs. DEFOIRDT Nele (UGENT – Woodlab) Mr. D'HOLIESLAGER Dirk (Company DDS) Mrs. HONTIS Ingrid (FEDUSTRIA) Mrs. MEIRESONNE Linda (INBO) Mrs. MUSSCHE Sylvie (Bosgroep Oost-Vlaanderen Noord) Mr. OP DE BEECK Philip & Thierry (Armand Op de Beeck bvba) Mr. REUBENS Bert (ILVO) Mr. SCHEERLINCK Hans (Bosgroep Vlaamse Ardennen tot Dender) Mr. SEYNAEVE Jan (Bosgroep Zuiderkempen) Mr. SPAAS Jan Mrs. STEENACKERS Marijke (INBO) Prof. VAN ACKER Joris (UGENT – Woodlab) Mr. VAN DEN BULCKE JAN (UGENT – Woodlab) Mrs. VAN DIEST Karolien (Bosgroep Zuid-Limburg) Mrs. VAN LANGENHOVE Gudrun (ANB) Mr. VAN SWAAY Bob (Lignius) Mr. VANBEVEREN Stefan (UA) Mr. VANDEKERKHOVE Kris (INBO) Mr. VERCRUYSSE Dan (Chlarie) 1.1.1 Grants for poplar planting

1.1.2 Criteria for Sustainable Forest Management and the delineation of the Flemish

Ecological Network

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1.1.3 Short Rotation Forestry in Flanders

Linda Meiresonne

INBO - Research Institute for Nature and Forest

Linda.Meiresonne@inbo.be By the decree of the Flemish Government of June 20th 2006 short rotation forestry (SRF), defined as the cultivation of fast growing woody plants, from which the above ground biomass is periodically harvested with a maximum of 8 years after planting or previous harvest, is no longer considered as subjected to the Forest Decree. This means that SRF can be considered as an agricultural crop.

SRF and CAP (Common Agricultural Policy) With the 2013 CAP reform, 30% of direct payments are linked to respecting three sustainable agricultural practices which are beneficial to environmental and climate change concerns, notably soil quality, biodiversity and carbon sequestration – the so-called "Greening" measures. Greening supports action to adopt and maintain farming practices that help meet environment and climate goals. Farmers receiving an area-based payment have to make use of various straightforward, non-contractual practices that benefit the environment and the climate. They include:

• diversifying crops • maintaining permanent grassland • ecological focus areas (EFA): farmers with arable areas exceeding 15 ha must ensure that at

least 5% of such areas is an 'ecological focus area' dedicated to ecologically beneficial elements. Ecological focus areas cover a broad range of features, including ones that affect biodiversity: fallow land, landscape features as hedges or wooded strips, trees in groups, field margins, ponds and ditches, buffer strips, agroforestry, strips along forest edges, short rotation forestry, afforested areas, catch crops or green cover and nitrogen fixing crops.

Specific for short rotation forestry the choice of tree species is limited to the following list: Alnus

glutinosa, Salix caprea, Salix alba, Salix viminalis, Ulmus laevis, Ulmus minor, Corylus avellana,

Populus nigra, Acer pseudoplatanus, Fraxinus excelsior, Tilia platyphyllos, Tilia cordata, Quercus

rubra, Sorbus aucuparia, Carpinus betulus, Betula pendula, Prunus avium, Castanea sativa.

This means that the use of culture poplars is excluded. Moreover the conversion factor of SRF is 0,3 which means that every hectare of SRF counts for 0,3 hectare of EFA In 2015 9200 Flemish farmers had to install ecological focus areas, from whom 15 have chosen for short rotation forestry, illustrating the lukewarm interest for this type of ecological focus area.

1.1.4 Agro-forestry

Bert Ruebens

Instituut voor Landbouw - en Visserijonderzoek (ILVO)

Burg. Van Gansberghelaan 109

9820 Merelbeke

Bert.Reubens@ilvo.vlaanderen.be Both the Common Agricultural Policy (CAP) and other policies affect the possibilities of agro-forestry in Belgium. In Flanders the submeasure 8.2 (previously 222) has been implemented. Since 2011, 80 % of the total plantation costs are refunded. There are no subsidies for maintenance costs. Agroforestry is eligible as ecological focus area if it has been established under submeasure 8.2. In Wallonia the submeasure 8.2 has not been implemented and hence agroforestry is not eligible as

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ecological focus area. New subsidies are provided by DNF (Department of Nature and forests) for supporting agroforestry systems (plantation and maintenance – up to 80 % of the costs): trees, hedges, linear-short-rotation-coppice (including high productive species like poplar). Modification of legal documents/texts (Forest Decree – land planning rules / Code de Développement Territorial – veldwetboek) have been agreed upon to cover both definition and modalities for agroforestry systems in both regions, e.g. no need for tree-felling permits on agroforesty area. Discussions with alnd-owners and the farmers lobby concerning a revision of the law on farm lease modalities (bail à ferme / pachtwet) are to be considered for new developments in agroforestry. Since the new subsidies in 2011 in Flanders approximately 95 ha have been planted under this system and every year an increase can be observed. There are also agroforestry areas installed without subsidies. Planting density is on average 56 trees/ha (range 30-200). Walnut and poplar are the most used species, but a larger variety is commonly used. One third of the area is related to organic farming.

I.2 Walloon Region Patrick Mertens

Département de l'Etude du milieu naturel et agricole

Direction du Milieu forestier

Patrick.Mertens@spw.wallonie.be

Since the 24th session of the IPC (India), the Walloon Regional Commission of Poplar (CRWP) met fourteen times. At all these meetings, members were informed of news, applications, and guidelines adopted by the IPC. The Members have also contributed to the following items, specific to our Regional Commission:

� regional means of transformation of poplar wood, mainly the sawing products and the issues of thermally modified wood (including research results and industrial capacities);

� use of poplar and willows in “phytostabilisation” remediation systems; � participation in a comparative European cultivars test (following the Teisendorf meeting); � importance of biomass production in Wallonia.

Continuous attention was given to the ProPopulus issues. A very specific task was developed by the CRWP during this period. It is the organization of a one day meeting with the Regional Deciders on the positive environment effects of poplar growing.

This field day brought together a number of Walloon decision-makers with the message to increase awareness of the poplar potential in our context where environmental expectations are increasing. Four main parts where organized to open up this main objective: � describe the regional poplar owners, their traditional culture practices and the

environmental context of poplar culture; � -present the ecosystem services of poplar growing in Walloon Region; � -prove that poplar culture respects and restores the rural environment when producing

useful round wood � -show the transformed products of poplar culture

Another strategic task was worked out. Recent issues of reproductive material have to be compared to the previous cultivars (or varieties) to update the diversity of future plantations. Such a new trial was installed during winter 2014-15. During winter 2015-16, a replication of this trial has been also installed.

It is one of the matters that are important to keep up with the future potential of poplar culture in Walloon Region where timber of poplar can get significant in complement to coniferous wood

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marked. Beside the CRWP in the actual economic context, no other Institution is able assure the reproductive material testing.

The Regional importance of willows has been also pointed out. In 2013, the event “le jour de l’arbre” has been devoted to the willows. To prepare this event and the booklet describing the willows, our CRWP gave a main contribution to assure that a quite complete view is given to these genera. Other contribution going in the same direction of the use of the potential diversity of willows have been given to help the “Village du saule”. Composition of the CRWP:

Secretary: Mr Corneille FRANSSEN President: Mr Patrick MERTENS Vice-President: Mr Henri MARAITE Members: Mr Vincent COLSON Mr Lionel DELVAUX Mr François DE MEERSMAN Mr André DE TERCK Mr Christian de TOLLENAERE Mr René EVRARD † Mr Jean GRULOIS Mr Benoît JOUREZ Mr Claude LARCIN Mr Henri LECOMTE Mr Gilbert PICRON Mr Quentin PONETTE Mr Jacques RONDEUX Mr François RUCHENNE Mr Etienne SNYERS Mr François SOUGNEZ The CRWP is still part of the Walloon « Conseil Supérieur de la Forêt et de la Filière Bois ». This structure has been renewed in 2015.

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II. TECHNICAL INFORMATION 1. Identification, registration and varietal control

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2. Production Systems and Cultivation (a) Nursery

Poplar nurseries

Marleen Sevenants

Government of Flanders / Department of Agriculture and Fisheries

Sensitisation, Target Group Management and Plant Quality Division

marleen.sevenants@lv.vlaanderen.be

Jan Coussement

Sylva boomkwekerijen bvba

9950 Waarschoot

jan.coussement@sylva.be Data are available on the clonal distribution in the Flemish nurseries. Table 1 shows the annual amount of poplar plants sold over the last four years. After a drastic drop mainly during de planting seasons 2008-2009 and 2009-2010 as reported earlier we now observe a slight recovery over the last season. Table 1: Annual amount of poplar plants sold over the last 4 years from Flemish nurseries (sorted on amount sold in 2015-16).

CLONE 2011-2012 2012-2013 2013-2014 2014-2015 2015-2016

VESTEN 8717 10942 16556 17669 17586

KOSTER 5003 6702 9390 9988 8217

MUUR 3383 3098 3983 4234 3806

ROBUSTA 4407 3251 2203 2365 3771

OUDENBERG 3672 3195 5081 3914 3539

SKADO 2448 1312 1047 815 2045

POLARGO 880 1326 1393 1686 1731

BAKAN 2734 1440 899 2176 1708

GRIMMINGE 3403 3193 2122 2627 1706

TRICHOBEL 1710 549 620 1443 809

ALBELO 770 947 739 1230 779

SEROTINA 256 0 54 20 691

MARILANDICA 989 211 998 526 669

DANO 0 0 0 280 574

RONO 0 0 0 552 517

DEGROSSO 739 680 743 1121 469

BLAUWE VAN EXAERDE 112 129 227 177 354

GAVER 458 160 698 434 160

ISIÈRES 495 502 19 43 50

TRIPLO 0 0 0 250 0

A4A 145 35 0 0 0

FRITZI PAULEY 0 0 0 50 0

GHOY 249 160 0 0 0

TOTAL 40570 37832 46772 51600 49181

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The newer Belgian euramericana clones ‘Vesten’, ‘Muur’ and ‘Oudenberg’ and the Belgian (TxD)xD clone ‘Grimminge’ take the largest part of the production. There is also a significant production of foreign clones such as ‘Koster’. Also the last introduced clones ‘Skado’ and ‘Bakan’ are becoming important. An interesting feature is that still an important number of plants belonging to old poplar varieties are sold, such as ‘Robusta’ and ‘Marilandica’, the last one especially for landscaping purposes. The last years there also seems to be a tendency to focus only on one or two clones indicating it is useful to introduce on a regular basis new promising clones.

(b) Planted Forests Utilization of poplars and willows for bio-energy as a renewable source of energy

Linda Meiresonne

INBO - Research Institute for Nature and Forest

Linda.Meiresonne@inbo.be

A. Surface planted SRF period 2012 – 2015

During the period 2012 – 2015 nearly 40 hectares of SRF with poplar genotypes have been realized in Flanders. Most plantations have the wider design with a planting distance of 3 x 3 meters. In about one fifth of the plantations the Flemish clones (Muur, Vesten, Oudenberg, Grimminge, Bakan en Skado) were used.

B. Field experiments of short rotation forestry (SRF) of INBO During the period 2012 – 2015 INBO has established two experimental plantations of SRF at the nursery of Grimminge.

1. Field experiment 2011 Based on results of older experimental trials a collection of 95 very well performing poplar and willow clones was brought together on an experimental site in the nursery of INBO at Grimminge. Poplar clones # Willow clones #

Commercial clones 6 (Muur, Vesten Oudenberg, Grimminge, Bakan, Skado)

Commercial clones 2 (Tora, Belgisch Rood)

Back crosses (D x (TxD)) 53 Salix alba clones 12 DxTxM crosses 3 Salix rubens clones 4 T and T crosses 8 Salix alba x rubens 3 DxT cross 1 Salix fragilis 1 TxM crosses 2 Total 73 22 D = Populus deltoides; T : Populus trichocarpa; M = Populus maximowiczii

All clones were planted in lines of 20 cuttings (2 x 0.5 m) in duplicate (two blocks). After two years of growth (2013), whole tree harvesting and weighing of 10 ad random chosen plants per clone and per block was performed and after dry cleaning calculated to ton dry matter

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(DM) per year and per hectare. Poplar biomass production of the first harvest ranged from 1 to 11 ton DM per ha per yr and willow from 1 to 13 ton, indicating the wide range of production potential but also the existing of very promising performing clones. Two years later (2015), a selection of the best growing clones was made, based on the biomass performance of 2013 and on height and diameter measurements. Again ten plants per selected clone and per block (duplicate) were harvested and data processed as described above, together with the commercial clones present in the experimental site. The results of these second harvest shows the fulfillment of the promises. Furthermore it makes clear that only from the second harvest on the biomass production potential of selected clones can be really judged. Commercial clones ton DM ha

-1 yr

-1 Experimental clones # ton DM ha

-1 yr

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Poplar Muur 6.3 Back crosses (D x (TxD)) 11 10.4 – 17.2 Vesten 12.5 DxTxM crosses 3 13.7 – 17.9 Oudenberg 7.0 T cross 1 13.7 Grimminge 7.4 DxT cross 1 17.2 Bakan 13.9 TxM cross 1 16.4 Skado 16.3 Willow Tora 20.0 Salix alba clones 4 8.5 – 13.6 Belgisch Rood 8.9 Salix rubens clones 1 10.2 Salix alba x rubens 2 8.3 – 11.1

2. Field experiment 2014 In 2014 INBO became partner in the project of “Testing of poplar clones from EU member states for the use in short rotation coppice”, the so called Project EW13/14. The project was proposed by the Bavarian Office for Forest Seeding and Planting (ASP), Section Short Rotation Forests and Breeding at Teisendorf, Germany. The targets of the project are the approval of clones in the category “tested” and the facilitation of marketing of poplar clones from different EU countries. Partners beneath Belgium are: Bulgaria, Croatia, Czech Republic, France, Germany, Hungary, Italy, Romania, Serbia, Slovenia, Spain and Sweden, involving in total 22 institutes. A set of 15 clones plus 4-5 standard clones will be tested on all trial fields. A common data protocol was established: All field trials must be established according to a similar trial design. The following data have to be measured as minimum program for all common trials:

o Survival rate o Biomass yield at end of rotation period

Additional data of the local site conditions climate data has to be provided for each site. Each participant can add data collections according to his interests and local possibilities (e.g. fungi infestations as Melampsora, Dothichiza). Participants planning to record optional data should share this information in order to stimulate other partners to record these traits as well. Two rotation periods of 4 years are planned to get significant data about the performance of the clones. Final harvest after 4 years was a compromise at the project workshop between 2-3 years (Italy) and 6 years in northern countries (Sweden). No harvest will be done before 4 years. Countries where the development is slow, the prolongation of the rotation period will be discussed once again in October 2017. All plots in the common test fields have to show a common minimum design.

- Number of plants/plot: 40 (including border lines) 4 rows x 10 plants/plot => 16 plants in the center are evaluated

- Number of replications: 3

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- Spacing: 2,5 x 1m (as exception in some countries: 3,0 x 1,0 m) 2,5 m² x 40 plants = 100 m²/plot

- Borderline: Each plot will be surrounded by a row of the same clone in order to avoid side effects

The location of the Belgian experimental site is the nursery of INBO at Grimminge. This experimental plantation contents 23 clones, among them the 6 Belgian commercial clones (Muur, Vesten Oudenberg, Grimminge, Skado and Bakan). Additionally three partners (Italy - 2 plots, Germany and Hungary) of the Project EW13/14 were willing to plant a selection of experimental poplar (11 clones) and willow (5 clones) clones from the INBO selection and breeding program. Unfortunately the Hungarian plantation died by severe drought.

Research on short-rotation coppice poplar by the Research Centre of Excellence on Plant &

Vegetation Ecology (PLECO) - Department of Biology – University of Antwerp

Stefan Vanbeveren

Reinhart Ceulemans

Research Centre of Excellence on Plant & Vegetation Ecology (PLECO)

Department of Biology, University of Antwerp

Campus Drie Eiken - C 0.14

Universiteitsplein 1

Wilrijk (Antwerp)

Stefan.Vanbeveren@UAntwerp.be

Reinhart.Ceulemans@UAntwerp.be

The research centre of excellence on plant and vegetation ecology at the University of Antwerp conducts research on short-rotation coppices with poplar. This research is mainly centered around a plantation in Lochristi (Belgium). The plantation was established in 2010 on a mixture of 18 ha of agricultural land and pastures (Broeckx et al., 2012). The site is an operational scale plantation of short-rotation coppiced (SRC) poplar for the production of bioenergy, operated and managed by the University of Antwerp and Group Mouton (private SME company). From 2010 till 2015 the plantation was the experimental research site POPFULL, funded by the European Research Council and other funding agencies. The plantation was harvested twice (Berhongaray et al., 2013; Vanbeveren et al., 2015) and will be harvested a third time in February 2017. The woody chips are – via combustion or gasification – converted into renewable electricity and/or green heat. The main aims of the POFULL project were to make a full greenhouse gas balance, economic balance and energy balance. Since 2016 the plantation is a long-term (20 years) ecosystem observation station of the ICOS research infrastructure (ICOS = Integrated Carbon Observation System). Up to present, research focused on several ecophysiological aspects of poplar SRC, like: i) gas fluxes (Zona et al., 2013; Brilli et al., 2014); ii) growth, production and biomass (Verlinden et al., 2013; Broeckx et al., 2014); iii) physiology; iv) water flow (Fichot et al., 2015; Bloemen et al., 2016); v) harvesting technology (Vanbeveren et al., 2015); vi) economic viability of SRC plantations (El Kasmioui & Ceulemans, 2013); and vii) modelling (De Groote et al., 2015).

Ongoing research projects and funding at the site include the following: ESFRI – ICOS: Integrated Carbon Observation System

• ICOS is one of the flagships of the European Strategy Forum on Research Infrastructures (ESFRI). The overall goal is a better understanding of the greenhouse gas balance of Europe

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in relation to climatic changes. ICOS is a decentralized infrastructure consisting of distributed, standardized observation stations and central facilities. These observation stations are located on land (ecosystem towers and atmospheric towers) or in the ocean (ships, observation buoys). In a standardized way all observation stations monitor concentrations and fluxes of greenhouse gases, i.e. CO2 (carbon dioxide), but also CH4 (methane) and N2O (nitrous oxide). The SRC site is the only bioenergy observation station in the ICOS infrastructure.

• The ICOS infrastructure has a legal structure via a European Research Infrastructure Consortium (ERIC) signed on 15/10/2015 by nine countries. Duration: foreseen for 20 years.

• Websites: www.icos-ri.eu ; www.icos-belgium.be

SRF-OZO: Ozone and VOC measurements of a poplar bioenergy plantation • The aim of SRF-OZO is to assess the impact of poplar bioenergy cultivation on ozone and

biogenic volatile organic compound (BVOC) emissions. Campaigns of BVOC measurements are performed with two PTR-MS instruments (time-of-flight- and quadrupole-based) to measure ecosystem fluxes of VOCs with eddy covariance as well as leaf level volatile emissions. Fluxes of ozone are measured via eddy covariance.

• Project in collaboration with the Netherlands Organisation for Applied Scientific Research (TNO).

• SRF-OZO is funded by the European Commission within the frame of the Marie Sklodowska Curie Actions (People Programme) as an Individual Fellowship. Duration 01/10/2014 - 31/10/2016.

PHYSIO-POP: Physiological and environmental controls of water and ozone fluxes in a short rotation poplar plantation

• The goal of PHYSIO-POP is to study transpirational water loss and ozone fluxes of different poplar genotypes at different biological levels (leaf, tree, ecosystem) and time scales (daily, seasonal).

• PHYSIO-POP is funded by the European Commission within the frame of the Marie Sklodowska Curie Actions (Horizon 2020) as an Individual Fellowship. Duration 1/9/2015 – 31/8/2017.

HYPI: Assessment of isoprene emissions by hyperspectral data

• The goals of HYPI are (i) to identify the most useful vegetation index and the optimal strategy to determine isoprene emissions at leaf and ecosystem levels, and (ii) to explore how to incorporate newly developed vegetation indices into the MEGAN model (Model of Emissions of Gases and Aerosols from Nature).

• Project in collaboration with the Belgian Institute for Space Aeronomy (BIRA-IASB); the Flemish Institute for Technological Research (VITO) and the Centre for Ecological Research and Forestry Applications (CREAF-CSIC), Barcelona, Spain.

• HYPI is funded by the Belgian Science Policy Office (BELSPO) in the frame of the STEREO III programme. Duration 1/12/2015 – 31/07/2017.

• Website: tinyurl.com/ua-hypi

References to this work and abstracts period 2012- 2016, in chronological order Establishment and two-year growth of a bio-energy plantation with fast-growing Populus trees in

Flanders (Belgium): Effects of genotype and former land use.

Broeckx L.S., Verlinden M.S. and Ceulemans R. (2012) Biomass and Bioenergy, 42: 151-163. DOI: 10.1016/j.biombioe.2012.03.005 In April 2010, a large-scale Short Rotation Coppice (SRC) plantation was established with mainly poplar (Populus spp.) on a former agricultural site (cropland and pasture) in Flanders. The 12

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selected genotypes planted were assessed on establishment and production characteristics during the first two years of growth and were found highly productive, with a volume index ranging between 1.00 (±0.68) and 1.93 (±0.97) dm³ in growing season 1 (GS1) and between 2.75 (±1.70) and 11.91 (±6.33) dm³ in growing season 2 (GS2). Despite high survival rates of the cuttings after planting, competitive weeds and management operations increased tree mortality during the growing season from 3.4 % up to 18.2 % averaged over the entire plantation. Weed control therefore turned out to be the key factor in the establishment success. Only a minor influence of former land use was observed during GS1, which is explained by the non-limiting nutrient conditions on both former cropland and pasture, and which disappeared during GS2. These productive soils also explained the high growth rates, with an average tree height of 247 cm and 445 cm and stem diameter (at 22 cm height) of 25.21 mm and 40.73 mm after GS1 and GS2, respectively. Genotypic and parentage variations were found to be less pronounced during GS1, and increased during GS2 as expected. The maximum leaf area index and total leaf area duration were shown to be good indicators of production and growth performance. The results of this paper confirm the high potential of SRC with poplar on agricultural land for bio-energy purposes. Comparative analysis of harvesting machines on an operational high-density short rotation woody

crop (SRWC) culture: one-process versus two-process harvest operation.

Berhongaray G., El Kasmioui O. and Ceulemans R. (2013) Biomass and Bioenergy, 58: 333-342. DOI: 10.1016/j.biombioe.2013.07.003 (open access) Short rotation woody crops (SRWCs) are being studied and cultivated because of their potential for bioenergy production. The harvest operation represents the highest input cost for these short rotation woody crops. We evaluated three different harvesting machines representing two harvesting systems at one operational large-scale SRWC plantation. On average, 8 ton ha−1 of biomass was harvested. The cut-and-chip harvesters were faster than the whole stem harvester; and the self-propelled harvester was faster than the tractor-pulled. Harvesting costs differed among the harvesting machines used and ranged from 388 € ha−1 to 541 € ha−1. The realized stem cucng heights were 15.46 cm and 16.00 cm for the tractor-pulled stem harvester and the self-propelled cut-and-chip harvester respectively, although a cutting height of 10 cm was requested in advance. From the potential harvestable biomass, only 77.4% was harvested by the self-propelled cut-and-chip harvester, while 94.5% was harvested by the tractor-pulled stem harvester. An increase of the machinery use efficiency (i.e. harvest losses, cost) is necessary to reduce costs and increase the competitiveness of biomass with other energy sources. Financial Analysis of the cultivation of short rotation woody crops for bioenergy in Belgium: Barriers

and opportunities.

El Kasmioui O. and Ceulemans R. (2013) Bioenergy Research, 6: 336-350. DOI: 10.1007/s12155-012-9262-7 This paper analyses the financial performance of a poplar short rotation woody crop (SRWC) plantation in Belgium, from a farmer’s and an investor’s viewpoint, based on simulations from the newly developed model POPFINUA. The establishment, production and harvest costs were investigated to calculate the net present value (NPV) and the equivalent annual value (EAV) of the SRWC cultivation when the biomass chips were sold at a price of 40 € Mg−1 with a moisture content (m.c.) of 50 %. The calculated NPVs were 229 and −485 € ha−1, and the EAVs equalled 16.3 and −34.6 € ha−1 year−1 for the farmer’s and investor’s scenario, respectively. The break-even price at which the produced biomass could be sold at the farm gate excluding transport, handling, storage and profit margins of the involved companies was calculated using the levellised costs (LC) method and equalled 78.4 and 83.5 € oven-dried ton (odt)−1 for the farmer’s and investor’s viewpoint, respectively. Three harvesting strategies, applied on a SRWC plantation of 18.1 ha in Flanders (Belgium), were studied and compared. It became clear that preference should be given to more economic, small-scale harvesters instead of large-scale self-propelled harvesters, given the relatively limited surface available for SRWCs in Belgium. Furthermore, the inclusion of transportation over a

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distance of 50 km by truck increased the LC by 15.1 € odt−1. Moreover, subsidies such as establishment grants and/or yearly incentives proved indispensable to make this long-term investment profitable. This is particularly true for the scenario where an investor decides to cultivate SRWCs for energy purposes. Comparative study of biomass determinants of 12 poplar (Populus) genotypes in a high-density short-

rotation culture.

Verlinden M.S., Broeckx L.S., Van den Bulcke J., Van Acker J. and Ceulemans R. (2013) Forest Ecology

and Management, 307: 101-111. DOI: 10.1016/j.foreco.2013.06.062 (open access) The success of the production of renewable bioenergy with short-rotation coppice (SRC) cultures primarily depends on their sustainability and biomass yield. The choice of the genotypic materials largely determines how much biomass can be produced; therefore there is a need to study the performance of genotypes in situ to select the best performing ones. Twelve poplar (Populus) genotypes, of which two only recently commercialized, were planted in a large-scale operational SRC culture for the production of biomass for bioenergy. The objectives of the study were: (i) to describe and compare the 12 genotypes based on their growth, structural and developmental characteristics, and (ii) to analyze causal relationships between determining traits and productivity characteristics assessed at leaf, tree and population level by performing a hierarchical cluster analysis. The clustering of the poplar genotypes was clearly determined by parentage and genetic origin. Distinct differences between clusters were expressed in the biomass related traits; genotypes of similar parentage and origin showed comparable characteristics. Populus nigra genotypes were the least performing among the studied genotypes. The recently commercialized P. trichocarpa × P. maximowiczii hybrids on the other hand, were among the most productive genotypes. The P. deltoides × P. nigra hybrids showed intermediary results, with genotype Hees showing the highest biomass production among the 12 genotypes. As higher heating value was rather uniform among the genotypes, biomass production appeared the primary trait with regard to bioenergy production. This has significant implications for SRC cultures aiming at maximization of biomass production for maximum bioenergy yield. Besides the direct measurements of woody biomass growth (i.e. stem diameter), leaf area index is one of the most important early selection criteria for poplar with bioenergy purposes. The negative correlation of biomass and leaf rust infection reconfirmed the importance of disease vulnerability in breeding and selection programs. Fluxes of the greenhouse gases (CO2, CH4 and N2O) above a short-rotation poplar plantation after

conversion from agricultural land.

Zona D., Janssens I.A., Aubinet M., Gioli B., Vicca S., Fichot R., Ceulemans R. (2013) Agricultural and

Forest Meteorology, 169: 100-110. DOI: 10.1016/j.agrformet.2012.10.008 The increasing demand for renewable energy may lead to the conversion of millions of hectares into bioenergy plantations with a possible substantial transitory carbon (C) loss. In this study we report on the greenhouse gas fluxes (CO2, CH4, and N2O) measured using eddy covariance of a short-rotation bioenergy poplar plantation converted from agricultural fields. During the first six months after the establishment of the plantation (June–December 2010) there were substantial CO2, CH4, and N2O emissions (a total of 5.36 ± 0.52 Mg CO2eq ha−1 in terms of CO2 equivalents). Nitrous oxide loss mostly occurred during a week-long peak emission after an unusually large rainfall. This week-long N2O emission represented 52% of the entire N2O loss during one and an half years of measurements. As most of the N2O loss occurred in just this week-long period, accurately capturing these emission events are critical to accurate estimates of the GHG balance of bioenergy. While initial establishment (June–December 2010) of the plantation resulted in a net CO2 loss into the atmosphere (2.76 ± 0.16 Mg CO2eq ha−1), in the second year (2011) there was substaneal net CO2 uptake (−3.51 ± 0.56 Mg CO2eq ha−1). During the enere measurement period, CH4 was a source to the atmosphere (0.63 ± 0.05 Mg CO2eq ha−1 in 2010, and 0.49 ± 0.05 Mg CO2eq ha−1 in 2011), and was controlled by water table depth. Importantly, over the entire measurement period,

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the sum of the CH4 and N2O losses was much higher (3.51 ± 0.52 Mg CO2eq ha−1) than the net CO2 uptake (−0.76 ± 0.58 Mg CO2eq ha−1). As water availability was an important control on the GHG emission of the plantation, expected climate change and altered rainfall pattern could increase the negative environmental impacts of bioenergy. Simultaneous leaf- and ecosystem-level fluxes of volatile organic compounds from a poplar-based

SRC plantation.

Brilli F., Gioli B., Zona D., Pallozzi E., Zenone T., Fratini G., Calfapietra C., Loreto F., Janssens I.A. and Ceulemans R. (2014) Agricultural and Forest Meteorology, 187: 22-35. DOI: 10.1016/j.agrformet.2013.11.006 (open access) Emission of carbon from ecosystems in the form of volatile organic compounds (VOC) represents a minor component flux in the global carbon cycle that has a large impact on ground-level ozone, particle and aerosol formation and thus on air chemistry and quality. This study reports exchanges of CO2 and VOC between a poplar-based short rotation coppice (SRC) plantation and the atmosphere, measured simultaneously at two spatial scale, one at stand level and another at leaf level. The first technique combined Proton Transfer Reaction “Time-of-Flight” mass spectrometry (PTR–TOF–MS) with the eddy covariance method, to measure fluxes of a multitude of VOC. Abundant fluxes of isoprene, methanol and, to a lesser extent, fluxes of other oxygenated VOC such as formaldehyde, isoprene oxidation products (methyl vinyl ketone and methacrolein), methyl ethyl ketone, acetaldehyde, acetone and acetic acid, were measured. Under optimal environmental conditions, isoprene flux was mostly controlled by temperature and light. Differently, methanol flux underwent a combined enzymatic and stomatal control, together involving environmental drivers such as vapour pressure deficit (VPD), temperature and light intensity. Moreover fair weather condition favoured ozone deposition to the poplar plantation. The second technique involved trapping the VOCs emitted from leaves followed by gas chromatography-mass spectrometry (GC–MS) analysis. These leaf-level measurements showed that emission of isoprene in adult leaves and of monoterpenes in juvenile leaves are widespread across poplar genotypes. Detection of isoprene oxidation products (iox) emission with leaf-level measurements confirmed that a fraction of isoprene may be already oxidized within leaves, possibly when isoprene copes with foliar reactive oxygen species (ROS) formed during warm and sunny days.

The effect of a dry spring on seasonal carbon allocation and vegetation dynamics in a poplar

bioenergy plantation.

Broeckx L.S., Verlinden M.S., Berhongaray G., Zona D., Fichot R. and Ceulemans R (2014) Global

Change Biology Bioenergy, 6: 473-487. DOI: 10.1111/gcbb.12087 (open access) In this study the seasonal variation in carbon, water and energy fluxes as well as in net primary productivity (NPP) of different tree components is presented for a 2-year-old poplar (Populus spp.) plantation. A thorough ecophysiological study was performed at ecosystem scale, at tree and at leaf level, in this high-density bioenergy plantation. Seasonal variation in NPP and fluxes was analysed in relation to meteorological parameters at the field site. The growing season length in terms of carbon uptake was controlled by leaf area development until the maximum leaf area index (LAImax) was reached. Afterwards, a shift to belowground carbon allocation was observed. A dry period in spring caused a reduced leaf area production as well as a decrease in net ecosystem exchange and gross primary production (GPP) due to stomatal closure. Water use efficiency and fine root growth increased in response to limiting soil water availability in the root zone. When soil water availability was not limiting, GPP was controlled by a decrease in solar radiation and air temperature. The results of this study indicate that the productivity of recently established bioenergy plantations with fast-growing trees is very sensitive to drought. The interaction between soil water availability and factors controlling ecosystem GPP is crucial in assessing the CO2 mitigation potential under future climate conditions.

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ORCHIDEE-SRC v1.0: an extension of the land surface model ORCHIDEE for simulating short rotation

coppice poplar plantations.

De Groote T., Zona D., Broeckx L.S., Verlinden M.S., Luyssaert S., Bellassen V., Vuichard N., Ceulemans R., Gobin A. and Janssens I.A. (2015) Geoscientific Model Development, 8: 1461-1471. DOI: 10.5194/gmd-8-1461-2015 (open access) Modelling biomass production and the environmental impact of short rotation coppice (SRC) plantations is necessary for planning their deployment, as they are becoming increasingly important for global energy production. This paper describes the modification of the widely used land surface model ORCHIDEE for stand-scale simulations of SRC plantations. The model uses weather data, soil texture and species-specific parameters to predict the aboveground (harvestable) biomass production, as well as carbon and energy fluxes of an SRC plantation. Modifications to the model were made to the management, growth, and allocation modules of ORCHIDEE. The modifications presented in this paper were evaluated using data from two Belgian poplar-based SRC sites, for which multiple measurements and meteorological data were available. Biomass yield data were collected from 23 other sites across Europe and compared to 22 simulations across a comparable geographic range. The simulations show that the model predicts very well aboveground (harvestable) biomass production (within measured ranges), ecosystem photosynthesis (R2 = 0.78, NRMSE = 0.064, PCC = 0.89) and ecosystem respiration (R2 = 0.95, NRMSE = 0.078 PCC = 0.91). Also soil temperature and soil moisture are simulated adequately, but due to the simplicity of the soil moisture simulation, there are some discrepancies, which also influence the simulation of the latent heat flux. Overall, the extended model, ORCHIDEE-SRC, proved to be a tool suitable for predicting biomass production of SRC plantations. Vulnerability to drought-induced cavitation in poplars: synthesis and future opportunities.

Fichot R., Brignolas F., Cochard H. and Ceulemans R. (2015) Plant, Cell and Environment, 38: 1233-1251. DOI: 10.1111/pce.12491 Vulnerability to drought-induced cavitation is a key trait of plant water relations. Here, we summarize the available literature on vulnerability to drought-induced cavitation in poplars (Populus spp.), a genus of agronomic, ecological and scientific importance. Vulnerability curves and vulnerability parameters (including the water potential inducing 50% loss in hydraulic conductivity, P50) were collected from 37 studies published between 1991 and 2014, covering a range of 10 species and 12 interspecific hybrid crosses. Results of our meta-analysis confirm that poplars are among the most vulnerable woody species to drought-induced cavitation (mean P50 = −1.44 and −1.55 MPa across pure species and hybrids, respecevely). Yet, significant variation occurs among species (P50 range: 1.43 MPa) and among hybrid crosses (P50 range: 1.12 MPa), within species and hybrid crosses (max.P50 range reported: 0.8 MPa) as well as in response to environmental factors including nitrogen fertilization, irradiance, temperature and drought (max. P50 range reported: 0.75 MPa). Potential implications and gaps in knowledge are discussed in the context of poplar cultivation, species adaptation and climate modifications. We suggest that poplars represent a valuable model for studies on drought-induced cavitation, especially to elucidate the genetic and molecular basis of cavitation resistance in Angiosperms. Operational short rotation woody crop plantations: manual or mechanized harvesting?

Vanbeveren S.P.P., Schweier J., Berhongaray G. and Ceulemans R. (2015) Biomass and Bioenergy, 72: 8-18. DOI: 10.1016/j.biombioe.2014.11.019 (open access) Harvesting is the most expensive, but the least investigated process in the cultivation of short rotation woody crops (SRWC). To get a better idea of the harvesting process (in terms of its performance, productivity, cost, soil compaction, cutting height and quality as well as biomass losses), we closely monitored the second harvest of a SRWC culture in Flanders (Belgium). We

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compared our results to the harvests of other, small European parcels. The trees at our site were harvested with both a manual and a mechanised (Stemster harvester) cut-and-store system, while the cut-and-chip system was analysed from an extensive literature survey. The production cost (to the edge of the field) at our site reached 426 (manual) and 94 (mechanised) € t−1, while the average values found in the literature are respectively 104 and 78 € t−1, versus 17 € t−1 for the cut-and-chip harvesting system. The productivity at our site reached 14 (manual) and 22 (mechanised) oven-dry tonnes per scheduled machine hour, while the average values found in the literature are respectively 15 and 23 t h−1. Based on the good performance (ha h−1) and producevity (t h−1) of the cut-and-chip system as well as its lower costs, this harvesting system is recommended for operational SRWC.

Water use of a multigenotype poplar short-rotation coppice from tree to stand scale.

Bloemen J., Fichot R., Horemans J.A., Broeckx L.S., Verlinden M.S., Zenone T. and Ceulemans R. (2016) Global Change Biology Bioenergy, DOI: 10.1111/gcbb.12345 Short-rotation coppice (SRC) has great potential for supplying biomass-based heat and energy, but little is known about SRC’s ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (Populus) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand-level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (Fs) measurements on individual plants vs. stand scale eddy covariance flux data during a 39-day intensive field campaign in late summer 2011. Daily stem diameter variation (ΔD) was monitored simultaneously with Fs to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ΔD (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

Agroforestry in Flanders: An economically profitable answer to the demand for agro

ecological production methods

Bert Ruebens

Instituut voor Landbouw - en Visserijonderzoek (ILVO)

Burg. Van Gansberghelaan 109

9820 Merelbeke

Bert.Reubens@ilvo.vlaanderen.be

Agroforestry offers many opportunities to enhance farm resilience and respond to future challenges in Flemish (and West European) agriculture. Some examples are diversification in production and supplying a wide range of ecosystem services. Economically speaking, the expected increase in demand for biomass and high-quality wood products may make agroforestry a shock-proof investment for farmers. Agroforestry potentially meets the social demand for eco-efficient agro-ecological production methods while being economically profitable. Nevertheless, experience with agroforestry in Flanders is very limited. In addition to stumbling blocks regarding legal and administration issues, many technical, organizational and economical questions remain unanswered.

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With this project we aim to increase the opportunities for agroforestry in Flanders, through (1) an integrated collaboration throughout the entire chain of stakeholders, (2) co-development of research knowledge and practical experience, and (3) provision of solutions and guidance for the target group. We primarily focus on the soil-bound agricultural sector, but we also include other stakeholders such as tree nurseries and wood and biomass processing plants. The overall project objective is to create a breakthrough in a relatively short time of feasible, profitable and effective agroforestry systems in Flanders. This will be realized by conducting a participatory process with relevant stakeholders, fueled both by in-depth research and effective dissemination of knowledge and experience. More specific objectives are:

• Evaluating opportunities for various agroforestry systems in Flanders; • Increasing knowledge of ecological interactions, ecosystem services, technical impact and

especially economic opportunities for a selection of agroforestry systems relevant to the Flemish agricultural context;

• Obtaining an increased understanding of intention, attitude, norms, perception and social identity of those involved, to overcome the psychological and social barriers to agroforestry adoption;

• Providing decision support guidelines, practical suggestions and innovative solutions to farming enterprises with regard to the application of agroforestry;

• Encouraging and assisting stakeholders in the implementation of agroforestry measures, adapted to a given set of farming and environmental conditions. This responds to the current demand for well-founded support for farmers having a specific demand for transition towards the application of agroforestry. With this project we therefore not only aim for a change in attitude but also effective adoption.

In this project, a participatory course is followed, through which co-development, consultation of stakeholders, transdisciplinary guidance of practitioners and capture of grassroot ideas are enabled. As such the project aims at maximizing the relevance and validity of the knowledge and experience gained and disseminated. This participatory course runs through the entire project with regular feedback to and from other work packages. Major outputs of the project are the development of an online knowledge platform, a practical guide and an integrated decision support tool.

Cultivating Salix spp for basketry and gardening

Dries Claes

Koepel van Vlaamse Bosgroepen vzw

Aanspreekpunt Privaat Beheer – Natuur en Bos vzw

driesjclaes@gmail.com

As part of the growing interest in old techniques basketery is very popular in workshops. The growing market of the garden decoration with the gardenshows bring new ideas of use of willow species in the garden. Most used is the Salix fragilis, also known as crack willow and Salix viminalis or basket willow. They are both native to Europe and found in wild in risparian habitats. These habitats found in woodland are often protected for biodiversity reasons in Belgium (Natura 2000). The cultivation of willow could give an alternative source of income for the lands that are to wet for normal agriculture. It can be cultivated without fertilizers, chemical weedcontrol and other non-biological aditionals. But cultivation of Salix spp. will be seen as agriculture as it is harvested every 1 or 2 years. The production could not be realised on a large scale in woodland as it would not be considered as a normal threatment in woodconservation as seen by the law.

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(Picture from http://www.aarde-werkdestegge.nl/)

There is a growing interest for workshops where people can learn to make their own baskets and other household utensils and this is mainly with crack and basket willow. Willow is perfect material to make creative figures and to combine with other material where willow is for example easy to weave between the bars of an iron gate or to make a barrier or hedge. A new and growing market is the use in gardening for garden closures, railings for plants, retaining walls and to build huts. For these purposes other species of willow are also used and local sources can be found in a nearby wood but there are also some professional cultivators who can deliver greater amounts of products.

(Picture from BVBA Salix De Vos)

One of these new markets is for retaining walls and river embankments. The government asks in there scope of the public works or playgrounds to use natural material and local products or certified or not treated with toxic products. Willow mats is one of these products that is natural and cost efficient for retaining walls. Another increasing market is for energy (short rotation coppice), effluent treatment, in wastewater gardens, and in cadmium phytoremediation for water purification. (Perttu, K. L. and Kowalik, P. J. (1997)). Salix vegetation filters for purification of waters and soils. Biomass and Bioenergy, Volume 12, Issue 1, 1997, Pages 9-19. Elsevier Science Ltd.). For these purposes the company BVBA De Vos Salix has developed woven mats of fresh willows that can be rolled on the ground and will immediately start growing with a very fast effect of afforestation (http://devossalix.be/). A specific market is for use in wine yards where the small willow is used to bind the wine ranks instead of using metal or plastic binders. The choice of origin of Salix spp. is very important to have the right stiffness. People can often find willow branches in local woods. There is still some local tradition to cultivate like in the Biesbosch (The Netherlands). For harvesting there are mechanical solutions on the market. We found a company in Belgium, BVBA De Vos Salix (http://devossalix.be/) that is largely

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automated in harvesting and producing different products with weaving techniques and deliver in while Europe and even outside of Europe. Sources : www.devossalix.be; www.wilgen.be; www.bleeslat.nl; www.ecohout.be; www.vlechterij.nl; www.griendhouthandel.nl

(c) Indigenous Forests

Populus x canescens (Grey Poplar)

Linda Meiresonne

INBO - Research Institute for Nature and Forest

Linda.Meiresonne@inbo.be Introduction Populus x canescens is a natural hybrid of Populus tremula and Populus alba. It is a tree species with important silvicultural advantages. As an indigenous pioneer tree he creates easy a forest climate in afforestation projects. Because of his vague soil conditions he can be planted on nearly all soil types. His timber qualities are similar to those of the commercialized culture poplars. In the framework of the realization of the criteria Sustainable Forest management and the interest for indigenous species, Grey poplar becomes again an attractive tree species. INBO started in 2015 a project to select appropriate Populus x canescens clones for adoption on the List of Recommended Provenances. Background During two collecting campaigns (1999 and 2003) clones of Populus x canescens were gathered in mostly old forest locations all over the Flemish region. More than 30 phenotypes were collected. DNA-analysis reduced these collection to 17 genotypes. Asexual reproduction was performed by in vitro propagation. From 2003 till 2008 several one tree plot plantations were established, spread over Flanders. Some clones are present at each location, others only in 2 or 3. Each planting contains at least 8 different clones. Measurements 2015-2016 In 2015 and 2016, 7 of these plantations (total amount of trees 932) were subject of following measurements:

- Circumference 2015, circumference 2016 and yearly circumference increment - Form of the stem (straightness) - Presence of forks at several heights (low, halfway, top) - Angle of branches - Thickness of branches - Number of heavy branches - Diameter in two directions as a measure of cylindrical stem shape

Clonal selection All measurements were subject of a statistical analysis. The research question is whether there is a difference between these 17 clones, based on the range of characteristics measured on all trees. To evaluate all characteristics at once, a multivariate analysis is preferred. However, trees in the same plantation are expected to be correlated. To take this into account, a univariate mixed effects model is fitted to each outcome variable separately, using the correct link functions (identity, log, logit, cumulative logit).

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Based on each separate analysis the clones were given ranks, which can be summed to obtain a first ranking of the clones. In this way, however, we do not consider the fact that certain variables are correlated (different fork variables), or that certain variables are less important (angle of branches). To address this shortcoming, we performed a principal components analysis (PCA) to find a set of uncorrelated variables with an intuitive interpretation. On top of this, a k-means clustering split the clones into several groups to give more insight in which clones are good and which are not. Since working with ranks constitutes loss of information (no absolute differences between the clones), we also carried out the above PCA and k-means clustering on the random intercepts of the separate mixed model analyses. The outcome of the analysis was a cluster of 6 clones who are qualified by a good growth, a straight stem and few forks. Further analysis needs to give output about the growth increment and cylindrical stem shape. Wood properties In order to evaluate the possibilities of Grey Poplar as a worthy successor of the Euramerican poplar clones, attention has to be paid to the wood properties. Grey Poplar has a higher wood bulk density than common poplars, resulting in a stronger wood. The proportion tension wood is higher, but more diffuse spread, which means that the technological consequences are less problematic. In general wood of Grey poplar can be used in all common practices of poplar wood. Gluing, hammering and screwing are no problem. Also all applications based on veneering are possible, as the uniform distribution of the tension wood leads to a more effective drying process, compensating the disadvantage of the oval stem form. To enlarge the knowledge of the wood of Grey poplar, trees of the six selected clones will be cut in one of the research plantations. Stems will be veneered (DDS factory) and wood samples will be subject of technological analysis (Woodlab, UGent). Clonal propagation A successful introduction of Grey poplar on the tree market needs an easily applied clonal propagation method. Root cuttings is the most common propagation method of Grey Poplar, but is characterized by low efficiency because of the high variability in tallness of the plants. Grey poplar cannot be cut by winter or by summer cuttings. Only winter cuttings with wood of more than one year old seem to guarantee an adequate success. Further research of this production system is needed. In vitro propagation is a rapid, easy but rather expensive method for the multiplication of Grey Poplar. Only in case of huge amounts these propagation method can be applied. (d) Agroforestry and Trees Outside Forests

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3. Genetics, Conservation and Improvement Early assessment of poplar and willow wood properties: selection of parameters and their

predictability.

Lieven De Boever, Jan Van den Bulcke, Joris Van Acker

WOOD.BE

Hof-ter-vleestdreef 3, 1070 Brussels

Ghent University, Woodlab

Coupure links 653, 9000 Ghent lieven@wood.be, Joris.Vanacker@ugent.be

Both growth features as well as density and dimensional stability were assessed on their variability. Although poplar and willow are categorized as fast growing, still a broad spectrum of growth vigour is displayed. However, more important than growth rate is the stem form and ovality, more clearly showing the potential of high processing yields for the respective clones. Tension wood is insufficiently described by its surface of volume weighted averages per clone. Variability of this growth feature has to be furthermore outlined by parameters characterizing the spatial distribution. The Tension wood index (TWI20) and the Tension wood diffusion coefficient (TWDC100) were introduced. Both parameters figure the degree of diffuse distribution of tension wood and have to be considered together with the total amount of tension wood fibres when classifying clones. Density is considered the most important material characteristic. Variability in density is not adequately described with mean value and standard deviation. Poplar or willow clones displaying the same mean density, can differ significantly in how density values are distributed around the stem volume. Therefore, the Density uniformity index (DUI) and Density variability coefficient (DVC) were introduced to assess variation in density more accurately and to allow correlating density differences to end product performances. Dimensional stability is significantly related to density. Clones with higher density will display a lower degree of dimensional stability. However, this also implies that clones with high DUI (and low DVC) will have lower variability in shrinkage and swelling along longer wooden elements (beams of veneer sheets) and as such display lower differential tensions in changing climate conditions. Some parameters offer possibilities of early assessment. For the wood basic properties only the possibility of ranking clones on their variation in density (DUI) is possible. Since DUI values based for core wood samples (juvenile wood) deliver the same ranking of clones as the DUI based on the sapwood samples. However, absolute values of density cannot be predicted. The latter goes also for dimensional stability of poplar and willow clones, since the close correlation with density. In this study, no indications could be found that also variation in tension wood, and especially the spatial distribution of the gelatinous fibres could be predicted in an early growing stage.

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A generic platform for hyperspectral mapping of wood

Nele Defoirdt, Joris Van Acker, Jan Van den Bulcke

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Nele.Defoirdt@UGent.be

Sustainable forest management and durable use of wood is essential to guarantee future wood supply. Structural and chemical mapping can contribute to fit-for-purpose usage, as accurate and detailed knowledge of the material enables guided utilization and optimal performance of wood. The tool-chain presented in this paper, illustrated on a set of poplar disks for early selection, collects data in the NIR, visual and X-ray spectrum in only 30 minutes per wood disk. Flatbed scanning is confirmed as a cheap and fast technique to evaluate basis physical properties (a.o. cross sectional area and specific gravity). X-ray CT scanning is used for density mapping adding information on density variation between and within disks. Density, tension wood and alpha-cellulose and lignin content are mapped using chemometric modelling of infrared spectra. X-ray and NIR based density mapping showed good correlation, although NIR-based maps not show the same level of detail as X-ray scans do. Results of NIR-based hyperspectral mapping illustrated that tension wood zones were denser and contained more alpha-cellulose and less lignin which corresponds with the existence of the G-layer as described in literature. In all, the combination of high-end tools together with simple tools such as flatbed scanning allows for high throughput and high resolution quantitative mapping of some of the main poplar wood properties. Furthermore infrared scanning can be used to map density, tension wood and chemistry without the need for more complex, expensive and/or time consuming methods, yet with less accuracy and lower resolution, thus being applicable as a single tool for breeding selection.

Overview of activities on poplar within the Bioenergy Group of the VIB Department of

Plant Systems Biology and the UGent Department of Plant Biotechnology and

Bioinformatics

Wout Boerjan Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology

Technologiepark 927, 9052 Gent

woboe@psb.vib-ugent.be

Research in the Bioenergy Group at the VIB Department of Plant Systems Biology aims at supporting the transition from a fossil-based to a bio-based economy. Indeed, climate change urges to find alternatives for fossil resources to make biofuels and commodity products. Poplar is a promising wood-producing crop for the biorefinery. In the biorefinery, wood is converted to primary sugars, mainly glucose. Glucose can then be fermented to ethanol, or given as a carbon source to bacteria that are engineered to making building blocks for bioplastics, detergents, etc. The enzymatic conversion of biomass to primary sugars is hampered by the presence of lignin. Lignin needs to be extracted from the biomass by physical and chemical action and this is a costly process. Hence, our aim is to engineer poplar such that the lignin is easier to extract, i.e. with less chemicals and less energy. This will help overcoming the expensive biomass pretreatment step in the biorefinery (Harfouche et al., 2012; Vanholme et al., 2013a). To this end, we study the biosynthesis pathway of lignin to identify genes that can be used to tailor lignin in poplar. When transgenic trees (Populus

tremula x P. alba) with altered expression of these genes have been generated, they are propagated in the greenhouse till further analysis. Analyses typically consist of height measurements, Klason lignin analysis, cellulose analysis and hemicellulose analysis. Subsequently, we perform saccharification tests in which the enzymatic conversion from cellulose to glucose is measured with

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various pretreatments (none, alkali, acid). Finally, when the wood properties are sufficiently interesting from a valorization point of view, field trials are made to demonstrate that the new trait is maintained when trees are grown outdoor (Van Acker et al., 2014; Pilate et al., 2016). In collaboration with the University of Hasselt (Vangronsveld lab), it was also evaluated whether the microbiome of the field grown, lignin-modified poplars was affected (Beckers et al., 2016). In collaboration with the UGent Lab of Chemical Technology, the pyrolysis properties of the transgenic wood were evaluated (Toraman et al., 2016). Although bioethanol form poplar wood should be a viable option to supply biofuels to the EU (Littlewood et al., 2014), GM regulations strongly impede the market introduction of GM trees in Europe (Custers et al., 2016). In addition to genetic engineering, we also evaluated a new breeding approach called Breeding with Rare Defective alleles (BRDA) (Vanholme et al., 2013b). In addition to applied research, we have also performed more fundamental work; we discovered the biological role of PCBER, the most abundant poplar xylem protein (Niculaes et al., 2014). References to this work and abstracts period 2012- 2016 Lessons from 25 Years of GM Tree Field Trials in Europe and Prospects for the Future. G. Pilate, I. Allona, W. Boerjan, A. Déjardin, M. Fladung, F. Gallard, H. Häggman, S. Jansson, R. Van Acker and C. Halpin. Springer Science+Business Media Dordrecht. 2016 C. Vettori et al. (eds.), Biosafety of Forest Transgenic Trees, Forestry Sciences 82, DOI 10.1007/978-94-017-7531-1_4 67 It is common agronomic practice to perform a formal evaluation of the behaviour of new varieties under natural field conditions. Accordingly, shortly after the optimization of genetic engineering techniques on trees, a number of field trials were set up to assess GM trees modified for different genes. Here, we review the work that has been done in this arena in Europe over the last 25 years, and summarize what we learned from these experiments. GM tree field trials remain the exception rather than the rule in Europe. Several trials have been destroyed by anti-GMO activists and it is becoming increasingly difficult to obtain authorization for a GM tree field trial. These increasing constraints on GM tree trials within. Potential of genetically engineered hybrid poplar for pyrolytic production of bio-based phenolic

compounds.

Toraman HE, Vanholme, Borén E, Vanwonterghem Y, Djokic MR, Yildiz G, Ronsse, Prins W, Boerjan W, Van Geem KM, Marin GB. Bioresour Technol. 2016 May ;207:229-36. Wild-type and two genetically engineered hybrid poplar lines were pyrolyzed in a micro-pyrolysis (Py-GC/MS) and a bench scale setup for fast and intermediate pyrolysis studies. Principal component analysis showed that the pyrolysis vapors obtained by micro-pyrolysis from wood of caffeic acid O-methyltransferase (COMT) and caffeoyl-CoA O-methyltransferase (CCoAOMT) down-regulated poplar trees differed significantly from the pyrolysis vapors obtained from non-transgenic control trees. Both fast micro-pyrolysis and intermediate pyrolysis of transgenic hybrid poplars showed that down-regulation of COMT can enhance the relative yield of guaiacyl lignin-derived products, while the relative yield of syringyl lignin-derived products was up to a factor 3 lower. This study indicates that lignin engineering via genetic modifications of genes involved in the phenylpropanoid and monolignol biosynthetic pathways can help to steer the pyrolytic production of guaiacyl and syringyl lignin-derived phenolic compounds such as guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-vinylguaiacol, syringol, 4-vinylsyringol, and syringaldehyde present in the bio-oil. EU Regulations Impede Market Introduction of GM Forest Trees. Custers R, Bartsch D, Fladung M, Nilsson O, Pilate G, Sweet J, Boerjan W. Trends Plant Sci. 2016 Apr; 21(4):283-5. Biotechnology can greatly improve the efficiency of forest tree breeding for the production of biomass, energy, and materials. However, EU regulations impede the market introduction of

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genetically modified (GM) trees so their socioeconomic and environmental benefits are not realized. European policy makers should concentrate on a science-based regulatory process. Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome. Beckers B, Op De Beeck M, Weyens N, Van Acker R, Van Montagu M, Boerjan W, Vangronsveld J. Proc Natl Acad Sci U S A. 2016 Feb 23; 113(8):2312-7. Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement. Phenylcoumaran benzylic ether reductase prevents accumulation of compounds formed under

oxidative conditions in poplar xylem. Niculaes C, Morreel K, Kim H, Lu F, McKee LS, Ivens B, Haustraete J, Vanholme B, Rycke RD, Hertzberg M, Fromm J, Bulone V, Polle A, Ralph J, Boerjan W. Plant Cell. 2014 Sep; 26(9):3775-91. Phenylcoumaran benzylic ether reductase (PCBER) is one of the most abundant proteins in poplar (Populus spp) xylem, but its biological role has remained obscure. In this work, metabolite profiling of transgenic poplar trees downregulated in PCBER revealed both the in vivo substrate and product of PCBER. Based on mass spectrometry and NMR data, the substrate was identified as a hexosylated 8-5-coupling product between sinapyl alcohol and guaiacylglycerol, and the product was identified as its benzyl-reduced form. This activity was confirmed in vitro using a purified recombinant PCBER expressed in Escherichia coli. Assays performed on 20 synthetic substrate analogs revealed the enzyme specificity. In addition, the xylem of PCBER-downregulated trees accumulated over 2000-fold higher levels of cysteine adducts of monolignol dimers. These compounds could be generated in vitro by simple oxidative coupling assays involving monolignols and cysteine. Altogether, our data suggest that the function of PCBER is to reduce phenylpropanoid dimers in planta to form antioxidants that protect the plant against oxidative damage. In addition to describing the catalytic activity of one of the most abundant enzymes in wood, we provide experimental evidence for the antioxidant role of a phenylpropanoid coupling product in planta. Improved saccharification and ethanol yield from field-grown transgenic poplar deficient in

cinnamoyl-CoA reductase. Van Acker R, Leplé JC, Aerts D, Storme V, Goeminne G, Ivens B, Légée F, Lapierre C, Piens K, Van Montagu MC, Santoro N, Foster CE, Ralph J, Soetaert W, Pilate G, Boerjan W. Proc Natl Acad Sci U S A. 2014 Jan 14; 111(2):845-50. Lignin is one of the main factors determining recalcitrance to enzymatic processing of lignocellulosic biomass. Poplars (Populus tremula x Populus alba) down-regulated for cinnamoyl-CoA reductase

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(CCR), the enzyme catalyzing the first step in the monolignol-specific branch of the lignin biosynthetic pathway, were grown in field trials in Belgium and France under short-rotation coppice culture. Wood samples were classified according to the intensity of the red xylem coloration typically associated with CCR down-regulation. Saccharification assays under different pretreatment conditions (none, two alkaline, and one acid pretreatment) and simultaneous saccharification and fermentation assays showed that wood from the most affected transgenic trees had up to 161% increased ethanol yield. Fermentations of combined material from the complete set of 20-mo-old CCR-down-regulated trees, including bark and less efficiently down-regulated trees, still yielded ∼ 20% more ethanol on a weight basis. However, strong down-regulation of CCR also affected biomass yield. We conclude that CCR down-regulation may become a successful strategy to improve biomass processing if the variability in down-regulation and the yield penalty can be overcome. Breeding with rare defective alleles (BRDA): a natural Populus nigra HCT mutant with modified lignin

as a case study. Vanholme B, Cesarino I, Goeminne G, Kim H, Marroni F, Van Acker R, Vanholme R, Morreel K, Ivens B, Pinosio S, Morgante M, Ralph J, Bastien C, Boerjan W. New Phytol. 2013b May; 198(3):765-76. Next-generation (NG) sequencing in a natural population of Populus nigra revealed a mutant with a premature stop codon in the gene encoding hydroxycinnamoyl-CoA : shikimate hydroxycinnamoyl transferase1 (HCT1), an essential enzyme in lignin biosynthesis. The lignin composition of P. nigra trees homozygous for the defective allele was compared with that of heterozygous trees and trees without the defective allele. The lignin was characterized by phenolic profiling, lignin oligomer sequencing, thioacidolysis and NMR. In addition, HCT1 was heterologously expressed for activity assays and crosses were made to introduce the mutation in different genetic backgrounds. HCT1 converts p-coumaroyl-CoA into p-coumaroyl shikimate. The mutant allele, PnHCT1-Δ73, encodes a truncated protein, and trees homozygous for this recessive allele have a modified lignin composition characterized by a 17-fold increase in p-hydroxyphenyl units. Using the lignin pathway as proof of concept, we illustrated that the capture of rare defective alleles is a straightforward approach to initiate reverse genetics and accelerate tree breeding. The proposed breeding strategy, called 'breeding with rare defective alleles' (BRDA), should be widely applicable, independent of the target gene or the species. Towards a carbon-negative sustainable bio-based economy. Vanholme B, Desmet T, Ronsse F, Rabaey K, Van Breusegem F, De Mey M, Soetaert W, Boerjan W. Front Plant Sci. 2013a Jun 3;4:174. The bio-based economy relies on sustainable, plant-derived resources for fuels, chemicals, materials, food and feed rather than on the evanescent usage of fossil resources. The cornerstone of this economy is the biorefinery, in which renewable resources are intelligently converted to a plethora of products, maximizing the valorization of the feedstocks. Innovation is a prerequisite to move a fossil-based economy toward sustainable alternatives, and the viability of the bio-based economy depends on the integration between plant (green) and industrial (white) biotechnology. Green biotechnology deals with primary production through the improvement of biomass crops, while white biotechnology deals with the conversion of biomass into products and energy. Waste streams are minimized during these processes or partly converted to biogas, which can be used to power the processing pipeline. The sustainability of this economy is guaranteed by a third technology pillar that uses thermochemical conversion to valorize waste streams and fix residual carbon as biochar in the soil, hence creating a carbon-negative cycle. These three different multidisciplinary pillars interact through the value chain of the bio-based economy. Bioethanol from poplar: a commercially viable alternative to fossil fuel in the European Union. Littlewood J, Guo M, Boerjan W, Murphy RJ. Biotechnol Biofuels. 2014 Jul 29; 7:113.

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The European Union has made it a strategic objective to develop its biofuels market in order to minimize greenhouse gas (GHG) emissions, to help mitigate climate change and to address energy insecurity within the transport sector. Despite targets set at national and supranational levels, lignocellulosic bioethanol production has yet to be widely commercialized in the European Union. Here, we use techno-economic modeling to compare the price of bioethanol produced from short rotation coppice (SRC) poplar feedstocks under two leading processing technologies in five European countries. Our evaluation shows that the type of processing technology and varying national costs between countries results in a wide range of bioethanol production prices (€0.275 to 0.727/l). The lowest production prices for bioethanol were found in countries that had cheap feedstock costs and high prices for renewable electricity. Taxes and other costs had a significant influence on fuel prices at the petrol station, and therefore the presence and amount of government support for bioethanol was a major factor determining the competitiveness of bioethanol with conventional fuel. In a forward-looking scenario, genetically engineering poplar with a reduced lignin content showed potential to enhance the competitiveness of bioethanol with conventional fuel by reducing overall costs by approximately 41% in four out of the five countries modeled. However, the possible wider phenotypic traits of advanced poplars needs to be fully investigated to ensure that these do not unintentionally negate the cost savings indicated. Through these evaluations, we highlight the key bottlenecks within the bioethanol supply chain from the standpoint of various stakeholders. For producers, technologies that are best suited to the specific feedstock composition and national policies should be optimized. For policymakers, support schemes that benefit emerging bioethanol producers and allow renewable fuel to be economically competitive with petrol should be established. Finally, for researchers, better control over plant genetic engineering and advanced breeding and its consequential economic impact would bring valuable contributions towards developing an economically sustainable bioethanol market within the European Union. Accelerating the domestication of forest trees in a changing world.

Harfouche A, Meilan R, Kirst M, Morgante M, Boerjan W, Sabatti M, Scarascia Mugnozza G. Trends Plant Sci. 2012 Feb; 17(2):64-72. In light of impending water and arable land shortages, population growth and climate change, it is more important than ever to examine how forest tree domestication can be accelerated to sustainably meet future demands for wood, biomass, paper, fuel and biomaterials. Because of long breeding cycles, tree domestication cannot be rapidly achieved through traditional genetic improvement methods alone. Integrating modern genetic and genomic techniques with conventional breeding will expedite tree domestication. Breeders will only embrace these technologies if they are cost-effective and readily accessible, and forest landowners will only adopt end-products that meet with regulatory approval and public acceptance. All parties involved must work together to achieve these objectives for the benefit of society.

4. Forest Protection

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5. Harvesting and Utilization

Potential of thermally modified poplar wood for construction products

Lieven De Boever, Jan Van den Bulcke, Joris Van Acker

WOOD.BE

Hof-ter-vleestdreef 3, 1070 Brussels

Ghent University, Woodlab

Coupure links 653, 9000 Ghent

lieven@wood.be, Joris.Vanacker@ugent.be Thermal modification is a proofed technological transformation to improve the biological durability and/or the dimensional stability of wood. It has been demonstrated in literature that several modification treatments can be accurately controlled to increase the natural durability of poplar wood (originally attributed to durability class V or D5) to a durability class of preference. As such, the modification can be adapted to the end use of the intended product. However, most treatments alter the mechanical properties of the wood. The recorded lower strength values are not critical as such, however the induced variability of the mechanical parameters (elasticity and strength) is high and mostly unpredictable. The high levels of uncertainty limit the use of thermally treated poplar beams for timber constructions. It can be concluded that when poplar timber is used for structural applications mechanical grading should be performed. This grading will remain clone dependent, however groups of similar clones can be identified and allowed to be sorted with the same settings. Since mechanical properties for these low density hardwoods can be greatly influenced by overriding, currently not measured features as MFA it could be recommended to establish different settings for grading classes for the latter group of wood species (e.g. poplar, willow, eucalyptus) within EN 338. Thermally modified poplar wood can be used for ‘structural’ applications with positive characteristics like enhanced durability and/or dimensional stability but also the combination light weight, sufficient stiffness and adequate thermal insulation is aimed at. Limitations at this moment are the fact there is no certified grading system and most probable clonally dependency of grading.

Evaluation of decay resistance of heat-treated poplar wood

Benoit Jourez

DEMNA / SPW

Laboratoire de Technologie du Bois

23 Av Maréchal Juin b-5030 Gembloux

benoit.jourez@spw.wallonie.be In the 2012 Belgian report for the IPC, results of tests on heat-treated poplar wood following Besson process to determine the durability conferred by the treatment were presented. These tests revealed that the treated wood was classified into Class 1, i.e. “very durable timber”. Such performances allow the wood to be used outdoor for non-structural uses, without chemical preservative treatment. Despite these encouraging results, the long-term behaviour of the treated wood should be checked. Therefore, our laboratory has repeated these tests and we made new on heat-treated poplar wood by other process. It appears from these new tests that during the first two years after the heat treatment, the conferred durability evolves negatively: a too early determination of durability can thus be misleading. Moreover, the accelerated aging Tests EN84 (leaching procedure) and EN73 + (evaporative ageing procedure) tend to induce a slight increase in mass loss due to attack by wood-destroying fungi.

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Also, the conferred durability appeared to vary depending on the thermal processes applied. This indicates that treatment parameters have a clear impact on the properties imparted to the wood, and that their control is essential to ensure consistent production over time. Heat treatment of poplar wood is a promising process, which offers the opportunity to provide a significant added value to this species for indoor and outdoor uses due to the improved dimensional stability, durability and appearance. Poplar and willow wood as source for veneer based products: possibilities and limitations

Lieven De Boever, Jan Van den Bulcke, Joris Van Acker

WOOD.BE

Hof-ter-vleestdreef 3, 1070 Brussels

Ghent University, Woodlab

Coupure links 653, 9000 Ghent

lieven@wood.be, Joris.Vanacker@ugent.be Laminated veneer lumber (LVL) and plywood belong to the family of the engineered products, both based on reconstituting veneer sheets. Demand for engineered products is driven by many factors including diminishing old forests, new transformation technology and performance based building codes. Plywood and LVL products can be divided into two major groups. Structural products include all end-uses dealing with load-bearing applications (beams, I-joists, trusses, structural sheeting, rafters). These products are competing with large dimension timber, steel or concrete). Their main competitive factors are strength, weight, dimensional stability and price. Non-structural products include all end-uses without specific load-bearing function (window joinery, door frames, furniture parts). Main competition lies in products as MDF, particleboard and plastics. Competitive factors here are appearance, machinability, dimensional stability and also price. A group of more than 20 poplar clones and 10 willow clones was assessed on their veneer quality and to which extend they could be used for the production of plywood or LVL. More profound exploration of their wood properties (density, dimensional stability, tension wood occurrence,…) allows to predict the potential yield of specific clones. Therefore fitted distribution to measured wood properties and their higher moments (skewness and kurtosis) were needed. Moreover, it seems to be possible to rank clones at early age (6-8 years) to their potential use in veneer based products. Poplar and willow wood as a multi-use, local, raw material for a broad spectrum of green

construction products within the European Forestry wood chain

Lieven De Boever, Joris Van Acker

WOOD.BE

Hof-ter-vleestdreef 3, 1070 Brussels

Ghent University, Woodlab

Coupure links 653, 9000 Ghent

lieven@wood.be, Joris.Vanacker@ugent.be During a ten year research into more than 60 different poplar and willow clones the potential of a broad range of construction products was asssesed. Their density ranged as from 250 to 650 kg/m³ (oven dry). The outcome of the study describes the inherent properties of poplar and willow wood with special emphasis on assessing their variability and the possibility to select, control and improve the properties of interest. This immediately demonstrates the potential to use poplar and willow wood for almost all types of construction products.

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The often large variability of the macroscopic material properties has to be understood, suitably described and linked to the impact on specific constructive building stones in order to prevent the need for exaggerated safety factors which result in an uneconomic over-dimensioning when designing timber members. Furthermore, the study evaluated the inherent wood features with respect to the impact on transformation processes (primary processing and drying). Solid wood members or components in reconstituted engineered materials were classified with regard to their mechanical performance. Also the possibilities of chemical preservation and thermal modification were envisaged. Poplar and willow wood was evaluated as an additional source of raw material. The objective of this work was to compare the low-density hardwood species with the currently used (low-density) softwoods for load-bearing applications. Therefore, different product types as sawn solid timber of laminated timber were assessed using European standard codes and building regulations and calculations (Eurocode V). Moreover, the use of reconstituted materials (glulam, LVL and plywood) allowed to reduce or redistribute the number of wood defects (strength reducing factors), as such enhancing the yield of timber for value added construction products with prolonged service life. Adding shifting raw material flows within the European integrated forestry-wood chain does induce questions on economical feasibility (quality versus quantity) and environmental restrictions (sustainable and durable production systems). Therefore, the study handled on the impact on the forestry side as well as the wood column demonstrating the important potential of environmental friendly and local wood resources with an additional social impact by local employment and wide range of niche products. The concept of this research is an overall approach to assess rapidly growing low density hardwood species for load-bearing applications. Although this work specifically focuses on poplar and willow, the methodology will be transferable for used fast-growing low-density hardwood species growing worldwide (e.g. eucalyptus, limba, alder) as well as to other product groups (energy resources).

6. Environmental Applications

Potential use of poplars cultivars for forest biodiversity restoration: a brief literature

review

Luc De Keersmaeker, Kris Vandekerkhove, Arno Thomaes

Research Institute for Nature and Forest

Luc.DeKeersmaeker@inbo.be Most forests are complex ecosystems that take a long time to develop a high structural and functional diversity. The presence of old growth elements, e.g. veteran trees and dead wood, as well as a long and continuous presence of suitable habitat, are essential to support specialized biodiversity (Vandekerkhove et al. 2011). The recovery of forest biodiversity from open land is a slow process that depends on the connectivity with species source populations (see e.g. Brunet et al. 2011). For this reason conservation of remaining long-established forest, so-called ancient forest, is seen as a priority (Peterken 1977). The protection of well-developed and long-established forest habitat types in Europe is prescribed by the Natura 2000 legislation. The conversion of open land on suitable sites to forest could increase the connectivity between long-established forests, which is in agreement with the pan-European guidelines 11 and 24 for afforestation and reforestation (Ministerial Conference on the Protection of Forests in Europe 2009). These European forest biodiversity goals could be jeopardized by the increasing demand for biomass and wood, used to replace fossil resources. A high intensity of biomass harvesting is hardly compatible with the Natura2000 conservation goals. Plantation forestry could address the increasing

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demand for biomass and wood and could therefore relieve the pressure on forests with a high conservation value (Mantau et al. 2010, Gauthier 2011). On the right location and with the right management, plantation forests can support the restoration or defragmentation of forest habitat (Brockerhoff et al. 2008). Three ecological features of poplar cultivars stand out and can support both ecological and economical goals:

• Poplar cultivars are fast-growing trees • Poplar cultivars provide habitat for specific biodiversity • The leaf litter of poplar cultivars is rich in calcium

After plantation of trees and shrubs on open land the functional development of a forest ecosystem and the accompanying ecosystem services (e.g. above and belowground carbon sequestration) gradually develop. The high growth rate enables poplar cultivars to provide these services relatively fast (Fortier et al. 2016). In North America, poplar cultivars are planted as a shelter forest, to facilitate the establishment of native hardwood species (Stanturf et al. 2009, Dey et al. 2010; Boothroyd-Roberts et al. 2013). Poplar cultivars can have monumental dimensions and typical old growth features (e.g. cavities, dead branches) after a relative short period of time, which can promote forest biodiversity. The increase in population of the lesser spotted woodpecker (Dryobates minor) in the Mediterranean is explained by the maturing of poplar plantations in this region (Estrada et al. 2004 in Gil-Tena, A. et al. 2010). The flat bark beetle (Cucujus cinnaberinus), a saproxylic beetle species listed on the IUCN Red List as near-threatened and protected by Natura 2000, has a preference for Populus dead wood (Horak et al. 2010). Most of the breeding places of the Eurasian golden oriole (Oriolus oriolus) in the UK, the Netherlands and Belgium are located high in the crowns of hybrid Poplars, that are a substitute for the natural habitat of this species. The aforementioned species require specific habitat or habitat structures that are more or faster provided by poplar plantations than by plantations of other trees. Other species, mostly insects and fungi, are specific for trees of the genus Populus, but are nowadays mostly dependent of poplar cultivars as native species (e.g. Populus nigra) have become rare (see e.g. Heydemann 1982, De Lange 2015).

Figure 1 Forest soil pH-H2O, on former farmland planted 25 years before with 6 different tree species, is explained by the calcium concentration of the leaf litter. Fa: Fagus sylvatica; Qu: Quercus robur; Al: Alnus

glutinosa; Ti: Tilia spp.; Pr: Prunus avium; Po: Populus x Canadensis (De Schrijver et al. 2010)

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The third standout feature of poplars is the very high amount of calcium, found in the leaf litter of poplar cultivars as compared to other tree species (see Figure 1). A high calcium concentration in leaf litter stimulates the soil fauna and counteracts soil acidification (Reich et al. 2005). Long-term studies have demonstrated that many forests have acidified over the past decades, with negative effects on soil quality and forest vegetation composition (e.g. Falkengren-Grerup & Tyler 1993; Baeten et al. 2009). High deposition levels of nitrogen and sulphur are held at least partially responsable for this process (Nilsson & Grennfelt 1988). Tree species with calcium-rich litter, e.g poplar cultivars, can slow down this process and could be important for conservation of critical species in long-established forests (van Oijen et al. 2005), but could also promote the establishment of forest species sensitive to soil acidification on farmland converted to forest (Thomaes et al. 2011). It is important to mention that, in the case of restoration, the physical contact of new established forest stands with long-established forest is essential for recolonization of typical forest species (Peterken & Game 1984). Poplar plantations are often associated with destruction of open wetland and degradation of forest vegetation. There is no doubt that the replacement of long-established forests with a high structural diversity and associated biodiversity, by intensively managed, monospecific poplar plantations is a serious degradation. Yet poplar cultivars can play a prominent role in projects that aim forest restoration for biodiversity purposes on open land. Selection of fast-growing poplar trees with calcium-rich litter quality can slow down acidification, promote the slow maturing process of a forest ecosystem and provide ecosystem services in a shorter timespan than other tree species can. As it takes a long time for the specific biodiversity to establish on open land converted to forest, economic goals initially do not hamper conservation goals. As time goes by, the conservation value of such new-established forests will gradually increase and the intensity of forest management can simultaneously be lowered. References

Baeten L., Bauwens B., De Schrijver A., De Keersmaeker L., Van Calster H., Vandekerkhove K., Roelandt B., Beeckman H. & Verheyen K. 2009. Herb layer changes (1954-2000) related to the conversion of coppice-with-standards forest and soil acidification. Applied Vegetation Science 12: 187–197. Boothroyd-Roberts K, Gagnon D, Truax B (2013) Can hybrid poplar plantations accelerate the restoration of forest understory attributes on abandoned fields? Forest Ecology and Management 287, 77–89 Brockerhoff EG, Jactel H, Parrotta, JA, Quine CP, Sayer J (2008) Plantation forests and biodiversity: oxymoron or opportunity? Biodiversity and Conservation 17(5): 925-951 De Lange (2015). Populus trees and Russulaceae – a special ectomycorrhizal association in Flanders. MSc thesis UGent. Dey DC., Gardiner ES., Kabrick JM., Stanturf JA. & Jacobs DF. 2010. Innovations in afforestation of agricultural bottomlands to restore native forests in the eastern USA. Scandinavian Journal of Forest Research 25: 1-31. De Schrijver A, Janssens I, Staelens J, Wuyts K. (2010). Koolstof- en nutriëntenkringlopen [Carbon and nutrient cycles]. In: den Ouden J, Muys B, Mohren F, Verheyen K (eds). Bosecologie en Bosbeheer. Acco, Leuven Fortier J, Truax B, Gagnon D, Lambert F (2016) Potential for Hybrid Poplar Riparian Buffers to Provide Ecosystem Services in Three Watersheds with Contrasting Agricultural Land Use. Forests 7(2) doi: 10.3390/f7020037 Gauthier A (2011) Le bois, pilier de la politique de développement des énergies renouvelables? Forêt-entreprise doi15-19. Gil-Tena, A.; Brotons, L; Saura, S. (2010) Effects of forest landscape change and management on the range expansion of forest bird species in the Mediterranean region. Forest Ecology and Management 259(7): 1338-1346. Heydemann B. (1982). Der Einfluss der Waldwirtschaft auf die Wald-Ökosysteme aus zoologischer Sicht. Schriftenreihe Deutscher Rat für Landespflege 40:926–943. Horak, J., Vávrová, E., & Chobot, K. (2010). Habitat preferences influencing populations, distribution and conservation of the endangered saproxylic beetle Cucujus cinnaberinus (Coleoptera: Cucujidae) at the landscape level. European Journal of Entomology 107(1), 81.

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Mantau U, Saal U, Prins K, Steierer F, Lindner M, Verkerk H, Eggers J, Leek N, Oldenburger J, Asikainen A and Anttila P (2010) EUwood - Real potential for changes in growth and use of EU forests. Hamburg. Milwright R.D.P. 1998. Breeding biology of the Golden Oriole Oriolus oriolus in the fenland basin of eastern Britain, Bird Study 45: 320-330. Ministerial Conference on the Protection of Forests in Europe (1998) Annex 2 of the resolution L2, Pan-European Operational Level Guidelines for Sustainable Forest Management. Adopted at the Fifth Expert Level Preparatory Meeting of the Lisbon Conference on the Protection of Forests in Europe, 27–29 April 1998, Geneva, Switzerland. http://www.foresteurope.org/docs/MC/MC_lisbon_resolution_annex2.pdf. Nilsson J & Grennfelt P (1988) Critical loads for sulphur and nitrogen: report from a workshop held in Skokloster, Sweden, 19–24 March, 1988, Published by the Nordic Council of Ministers, Copenhagen. Peterken GF, Game M (1984) Historical factors affecting the number and distribution of vascular plant-species in the woodlands of Central Lincolnshire. Journal of Ecology 72, 155-182 Reich PB, Oleksyn J, Modrzynski J, Mrozinski P, Hobbie SE, Eissenhat D, Chroove J, Chadwick OA, Hale CM, Tjoelker MG. (2005) Linking litter calcium, earthworms and soil properties: a common garden test with 14 tree species. Ecol Lett 8: 811-818. Stanturf JA., Gardiner ES., Shepard JP., Schweitzer CJ., Portwood CJ. & Dorris LC. 2009. Restoration of bottomland hardwood forests across a treatment intensity gradient. Forest Ecology and Management 257: 1803-1814. Thomaes A, De Keersmaeker L, De Schrijver A, Vandekerkhove K, Verheyen K (2011) Can tree species choice influence recruitment of ancient forest species in post-agricultural forest? Plant Ecology 212, 573–584 Vandekerkhove K, De Keersmaeker L, Walleyn R, Köhler F, Crevecoeur L, Govaere L, Thomaes A, Verheyen K (2011) Reappearance of old-growth elements in lowland woodlands in northern Belgium: Do the associated species follow? Silva Fennica 45, 909–935 van Oijen D, Feijen M, Hommel P, den Ouden J, de Waal R (2005) Effects of tree species composition on within-forest distribution of understorey species. Applied Vegetation Science 8, 155-166.

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III. GENERAL INFORMATION

1. Administration and Operation of the National Poplar Commission or

equivalent Organization Flemisch Poplar Committee (Vlaams Populieren Comité – VPC)

Joris Van Acker

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Joris.VanAcker@UGent.be

On May 26th 2016 in Brussels a meeting was organised at the European Forestry House emphasizing the still strong will to interact, collaborate and seek opportunities for the future of poplar and willow in Flanders. A large group was involved in the set-up of this meeting and those effectively participating contributed intensively to the discussion on the future of poplar in Flanders and the options to continue selection and breeding at INBO. The following people (in alphabetical order) agreed to take part in the Flemish Poplar Committee (Vlaams Populieren Comité – VPC) and to have a network meeting at least once each year seeking increased interaction and support for poplar cultivation and related ecosystem services. Prof. BOERJAN Wout (VIB) Mr. CALUWAERTS Willy (Company CALUWAERTS) Prof. CEULEMANS Reinhart (UA) Mr. CLAES Dries (Bosgroep Dijle-Geteland) Mr. COUSSEMENT Jan (SYLVA) Mr. DE BOCK Marc (De Bock Marc Hout-Bois bvba) Mr. DE BOEVER Lieven (WOOD.BE) Mr. DE GROOT Maurits (APB) Mr. DE KEERSMAEKER Luc (INBO) Mr. DE MEERSMAN François (FEDEMAR) Mrs. DEFOIRDT Nele (UGENT – Woodlab) Mr. D'HOLIESLAGER Dirk (Company DDS) Mrs. HONTIS Ingrid (FEDUSTRIA) Mrs. MEIRESONNE Linda (INBO) Mrs. MUSSCHE Sylvie (Bosgroep Oost-Vlaanderen Noord) Mr. OP DE BEECK Philip & Thierry (Armand Op de Beeck bvba) Mr. REUBENS Bert (ILVO) Mr. SCHEERLINCK Hans (Bosgroep Vlaamse Ardennen tot Dender) Mr. SEYNAEVE Jan (Bosgroep Zuiderkempen) Mr. SPAAS Jan Mrs. STEENACKERS Marijke (INBO) Prof. VAN ACKER Joris (UGENT – Woodlab) Mr. VAN DEN BULCKE JAN (UGENT – Woodlab) Mrs. VAN DIEST Karolien (Bosgroep Zuid-Limburg) Mrs. VAN LANGENHOVE Gudrun (ANB) Mr. VAN SWAAY Bob (Lignius) Mr. VANBEVEREN Stefan (UA) Mr. VANDEKERKHOVE Kris (INBO) Mr. VERCRUYSSE Dan (Chlarie)

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Walloon Regional Commission of Poplar (CRWP)

Patrick Mertens

Département de l'Etude du milieu naturel et agricole

Direction du Milieu forestier

Patrick.Mertens@spw.wallonie.be The Walloon Regional Commission of Poplar (CRWP) is still part of the Walloon « Conseil Supérieur de la Forêt et de la Filière Bois ». This structure has been renewed in 2015. Composition of the CRWP: Secretary: Mr Corneille FRANSSEN President: Mr Patrick MERTENS Vice-President: Mr Henri MARAITE Members: Mr Vincent COLSON Mr Lionel DELVAUX Mr François DE MEERSMAN Mr André DE TERCK Mr Christian de TOLLENAERE Mr René EVRARD † Mr Jean GRULOIS Mr Benoît JOUREZ Mr Claude LARCIN Mr Henri LECOMTE Mr Gilbert PICRON Mr Quentin PONETTE Mr Jacques RONDEUX Mr François RUCHENNE Mr Etienne SNYERS Mr François SOUGNEZ

CENTRE DE POPULICULTURE DU HAINAUT 2012-2015

André Deterck

Centre de Populiculture du Hainaut a.s.b.l.

http://www.cph-populiculture.be

The “CENTRE DE POPULICULTURE DU HAINAUT” (CPH), founded in 1959, continued to promote poplar culture among its 300 members by organizing each year a symposium and two excursions. Since 2012, the seminars focused on the uses of poplar wood and poplars news such as the Poplar woolly aphid pest, the current state of cultivars sold in Europe, the quality of poplar wood and agroforestry systems with poplars. Several known speakers have occupied the chair as, Mrs Steenackers, Mrs Nervo, Dr Berthelot, and Prof. Van Acker. Two annual poplar field trips are organized, to show in trials the growth of the cultivars according to the actual climate, the type, moisture and other factors of soil and to identify the new pests and diseases. The field trips are also dedicated to show the performance of the new cultivars not yet issued on the market. CPH held a number of telephone calls which gave the evolution of rust in different places and for different cultivars.

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Foundation of ‘BOSFORUM’ and development of a long-term vision for forestry in Flanders

Jan Seynaeve

Coordinator Bosgroep Zuiderkempen

info@bosforum.be

http://www.bosforum.be/ In 2016, the ‘BOSFORUM’ was founded with a clear purpose: the development of a long-term vision for forestry in Flanders. The platform consists of experts and organizations from the timber and forest sector. The members want to develop a long term vision based on ecosystems. That means that beneath the biodiversity, also the relationship between forestry and climate, human health and bio-based economy will be taken in account. This project is also important for the management of poplar in Flanders. It will result in a better knowledge about the presence of poplar in Flanders and will help to define production targets and methods for the next 40 years. We hope to start at the end of 2016 and to finish at the beginning of 2018.

2. Literature

Research on poplars and willow at INBO

Research Institute for Nature and Forest (INBO)

Luc De Keersmaeker (email: Luc.DeKeersmaeker@inbo.be)

De Keersmaeker L (2013) Spatio-temporal patterns of vegetation recovery in post-agricultural forests on mesophilous sites. PhD thesis, Applied Biological Sciences: Land and Forest Management, UGent

Thomaes A, De Keersmaeker L, Van Calster H, De Schrijver A, Vandekerkhove K, Verstraeten G, Verheyen K (2012) Diverging effects of two contrasting tree species on soil and herb layer development in a chronosequence of post-agricultural forest. Forest Ecology and Management 278: 90-100

Thomaes A, De Keersmaeker L, De Schrijver A, Baeten L, Vandekerkhove K, Verstraeten G, Verheyen K (2013) Can soil acidity and light help to explain tree species effects on forest herb layer performance in post-agricultural forests? Plant and Soil 373: 183-199

Thomaes A (2013) Tree species effects on herb layer development in post-agricultural forests. PhD thesis, Applied Biological Sciences: Land and Forest Management, UGent

Thomaes A, De Keersmaeker L, Verschelde P, Vandekerkhove K, Verheyen K (2014) Tree species determine the colonisation success of forest herbs in post-agricultural forests: Results from a 9 yr introduction experiment. Biological Conservation 169: 238-247

Vanden Broeck A., Cox K., Michiels B., Verschelde P., Villar M. (2012) With a little help from my friends: hybrid fertility of exotic Populus x canadensis enhanced by related native Populus nigra. Biological invasions 14 (8): 1683 – 1696

Vanden Broeck A., Cox K., Villar M. (2012). Natural hybridization and potential seed set of sympatric Populus

nigra and Populus x canadensis along the river Ijzer in Flanders (Belgium). Plant Ecology and Evolution 145 (3): 341 - 349

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Research on short-rotation coppice poplar

Research Centre of Excellence on Plant & Vegetation Ecology (PLECO)

Department of Biology, University of Antwerp

Wilrijk (Antwerp)

Campus Drie Eiken - C 0.14

Universiteitsplein 1

Stefan Vanbeveren (email: Stefan.Vanbeveren@UAntwerp.be)

Reinhart Ceulemans (email: Reinhart.Ceulemans@UAntwerp.be)

2016

Bloemen J., Fichot R., Horemans J.A., Broeckx L.S., Verlinden M.S., Zenone T. and Ceulemans R. (2016) Water use of a multigenotype poplar short-rotation coppice from tree to stand scale. Global Change Biology

Bioenergy, DOI: 10.1111/gcbb.12345 Brilli F., Gioli B., Fares S., Zenone T., Zona D., Gielen B., Loreto F., Janssens I.A. and Ceulemans R. (2016) Rapid

leaf development drives the seasonal pattern of volatile organic compound (VOC) fluxes in a ‘coppiced’ bioenergy poplar plantation. Plant, Cell and Environment, 39: 539-555. DOI: 10.1111/pce.12638

Gebauer R., Vanbeveren S.P.P., Volarik D., Plichta R. and Ceulemans R. (2016) Petiole and leaf traits of poplar in relation to parentage and biomass yield. Forest Ecology and Management, 362: 1-9; DOI: 10.1016/j.foreco.2015.11.036 (open access)

Vanbeveren S.P.P., Gebauer R., Plichta R., Volarik D. and Ceulemans R. (2016) Nutrients and energy in proleptic branches and leaves of poplar under a short-rotation coppice. Biomass and Bioenergy, 85: 271-277. DOI: 10.1016/j.biombioe.2015.12.016 (open access)

Zenone T., Zona D., Gelfand I., Gielen B., Camino Serrano M. and Ceulemans R. (2016) CO2 uptake is offset by CH4 and N2O emissions in a poplar short rotation coppice. Global Change Biology Bioenergy, 8: 524-538. DOI: 10.1111/gcbb.12269 (open access)

2015

Berhongaray G. and Ceulemans R. (2015) Neglected carbon pools and fluxes in the soil balance of short-rotation woody biomass crops. Biomass and Bioenergy, 73: 62-66. DOI: 10.1016/j.biombioe.2014.12.002 (open access)

Berhongaray G., Verlinden M.S., Broeckx L.S. and Ceulemans R. (2015) Changes in belowground biomass after coppice in two Populus genotypes. Forest Ecology and Management, 337: 1-10. DOI: 10.1016/j.foreco.2014.10.035 (open access)

Broeckx L.S., Vanbeveren S.P.P., Verlinden M.S. and Ceulemans R. (2015) First vs. second rotation of a poplar short rotation coppice: leaf area development, light interception and radiation use efficiency. iForest-

Biogeosciences and Forestry, 8: 565-573. DOI: 10.3832/ifor1457-008 (open access) De Groote T., Zona D., Broeckx L.S., Verlinden M.S., Luyssaert S., Bellassen V., Vuichard N., Ceulemans R., Gobin

A. and Janssens I.A. (2015) ORCHIDEE-SRC v1.0: an extension of the land surface model ORCHIDEE for simulating short rotation coppice poplar plantations. Geoscientific Model Development, 8: 1461-1471. DOI: 10.5194/gmd-8-1461-2015 (open access)

Fichot R., Brignolas F., Cochard H. and Ceulemans R. (2015) Vulnerability to drought-induced cavitation in poplars: synthesis and future opportunities. Plant, Cell and Environment, 38: 1233-1251. DOI: 10.1111/pce.12491

Njakou Djomo S., Ac A., Zenone T., De Groote T., Bergante S., Faccioto G., Sixto H., Ciria Ciria P., Weger J. and Ceulemans R. (2015) Energy performances of intensive and extensive short rotation cropping systems for woody biomass production in the EU. Renewable and Sustainable Energy Reviews, 41: 845-854. DOI: 10.1016/j.rser.2014.08.058 (open access)

Vanbeveren S.P.P., Schweier J., Berhongaray G. and Ceulemans R. (2015) Operational short rotation woody crop plantations: manual or mechanized harvesting? Biomass and Bioenergy, 72: 8-18. DOI: 10.1016/j.biombioe.2014.11.019 (open access)

Verlinden M.S., Broeckx L.S. and Ceulemans R. (2015) First vs. second rotation of a poplar short rotation coppice: above-ground biomass productivity and shoot dynamics. Biomass and Bioenergy, 73: 174-185. DOI: 10.1016/j.biombioe.2014.12.012 (open access)

Verlinden M.S., Fichot R., Broeckx L.S., Vanholme B., Boerjan W. and Ceulemans R. (2015) Carbon isotope compositions (δ13C) of leaf, wood and holocellulose differ among genotypes of poplar and between

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previous land uses in a short-rotation biomass plantation. Plant, Cell and Environment, 38: 144-156. DOI:10.1111/pce.12383

Zenone T., Fischer M., Arriga N., Broeckx L.S., Verlinden M.S., Vanbeveren S.P.P., Zona D. and Ceulemans R. (2015) Biophysical drivers of the carbon dioxide, water vapor, and energy exchanges of a short-rotation poplar coppice. Agricultural and Forest Meteorology, 209: 22-35. DOI: 10.1016/j.agrformet.2015.04.009

2014

Brilli F., Gioli B., Zona D., Pallozzi E., Zenone T., Fratini G., Calfapietra C., Loreto F., Janssens I.A. and Ceulemans R. (2014) Simultaneous leaf- and ecosystem-level fluxes of volatile organic compounds from a poplar-based SRC plantation. Agricultural and Forest Meteorology, 187: 22-35. DOI: 10.1016/j.agrformet.2013.11.006 (open access)

Broeckx L.S., Fichot R., Verlinden M.S. and Ceulemans R. (2014) Seasonal variations in photosynthesis, intrinsic water-use efficiency and stable isotope composition of poplar leaves in a short-rotation plantation. Tree Physiology, 34: 701-715. DOI:10.1093/treephys/tpu057 (open access)

Broeckx L.S., Verlinden M.S., Berhongaray G., Zona D., Fichot R. and Ceulemans R (2014) The effect of a dry spring on seasonal carbon allocation and vegetation dynamics in a poplar bioenergy plantation. Global

Change Biology Bioenergy, 6: 473-487. DOI: 10.1111/gcbb.12087 (open access) Zona D., Gioli B., Fares S., De Groote T., Pilegaard K., Ibrom A. and Ceulemans R. (2014) Environmental controls

on ozone fluxes in a poplar plantation in Western Europe. Environmental Pollution, 184: 201-210. DOI: 10.1016/j.envpol.2013.08.032 (open access)

2013

Berhongaray G., El Kasmioui O. and Ceulemans R. (2013) Comparative analysis of harvesting machines on an operational high-density short rotation woody crop (SRWC) culture: one-process versus two-process harvest operation. Biomass and Bioenergy, 58: 333-342. DOI: 10.1016/j.biombioe.2013.07.003 (open access)

Berhongaray G., Janssens I.A., King J.S., Ceulemans R. (2013) Fine root biomass and turnover of two fast-growing poplar genotypes in a short-rotation coppice culture. Plant and Soil, 373: 269-283. DOI: 10.1007/s11104-013-1778-x (open access)

El Kasmioui O. and Ceulemans R. (2013) Financial Analysis of the cultivation of short rotation woody crops for bioenergy in Belgium: Barriers and opportunities. Bioenergy Research, 6: 336-350. DOI: 10.1007/s12155-012-9262-7

Njakou Djomo S., El Kasmioui O., De Groote T., Broeckx L.S., Verlinden M.S., Berhongaray G., Fichot R., Zona D., Dillen S.Y., King J.S., Janssens I.A., Ceulemans R. (2013) Energy and climate benefits of bioelectricity from low-input short rotation woody crops on agricultural land over a two-year rotation. Applied

Energy, 111: 862-870. DOI: 10.1016/j.apenergy.2013.05.017 (open access) Verlinden M.S., Broeckx L.S., Van den Bulcke J., Van Acker J. and Ceulemans R. (2013) Comparative study of

biomass determinants of 12 poplar (Populus) genotypes in a high-density short-rotation culture. Forest

Ecology and Management, 307: 101-111. DOI: 10.1016/j.foreco.2013.06.062 (open access) Verlinden M.S., Broeckx L.S., Wei H. and Ceulemans R. (2013) Soil CO2 efflux after land use change to a

bioenergy plantation with fast-growing Populus trees – influence of former land use, inter-row spacing and genotype. Plant and Soil, 369: 631-644. DOI: 10.1007/s11104-013-1604-5 (open access)

Verlinden M.S., Broeckx L.S., Zona D., Berhongaray G., De Groote T., Camino Serrano M., Janssens I.A., Ceulemans R. (2013) Net ecosystem production and carbon balance of an SRC poplar plantation during its first rotation. Biomass and Bioenergy, 56: 412-422. DOI: 10.1016/j.biombioe.2013.05.033 (open access)

Zona D., Janssens I.A., Aubinet M., Gioli B., Vicca S., Fichot R., Ceulemans R. (2013) Fluxes of the greenhouse gases (CO2, CH4 and N2O) above a short-rotation poplar plantation after conversion from agricultural land. Agricultural and Forest Meteorology, 169: 100-110. DOI: 10.1016/j.agrformet.2012.10.008

Zona D., Janssens I.A., Gioli B., Jungkunst H.F., Camino Serrano M. and Ceulemans R. (2013) N2O fluxes of a bio-energy plantation during a two years rotation period. Global Change Biology Bioenergy, 5: 536-547. DOI: 10.1111/gcbb.12019

2012

Broeckx L.S., Verlinden M.S. and Ceulemans R. (2012) Establishment and two-year growth of a bio-energy plantation with fast-growing Populus trees in Flanders (Belgium): Effects of genotype and former land use. Biomass and Bioenergy, 42: 151-163. DOI: 10.1016/j.biombioe.2012.03.005

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Broeckx L.S., Verlinden M.S., Vangronsveld J. and Ceulemans R. (2012) Importance of crown architecture for leaf area index of different Populus genotypes in a high-density plantation. Tree Physiology, 32: 1214-1226. DOI: 10.1093/treephys/tps083

El Kasmioui O. and Ceulemans R. (2012) Financial analysis of the cultivation of poplar and willow for bioenergy. Biomass and Bioenergy, 43: 52-64. DOI: 10.1016/j.biombioe.2012.04.006.

Research on biotechnology of poplar

Bioenergy Group

Department of Plant Systems Biology

Flanders Interuniversity Institute for Biotechnology (VIB)

Technologiepark 927, 9052 Gent

Wout Boerjan (email: woboe@psb.vib-ugent.be)

2016

Toraman, H. E., Vanholme, R., Borén,E., Vanwonterghem, Y., Djokic, M.R., Yildiz G.,Ronsse, F., Prins, W., Boerjan, W., Van Geem, K., M., and Marin G., B. (2016). Potential of genetically engineered hybrid poplar for pyrolytic production of bio-based phenolic compounds. Bioresource Technology, May;207:229-36.

Custers R, Bartsch D, Fladung M, Nilsson O, Pilate G, Sweet J, Boerjan W (2016). EU Regulations Impede Market Introduction of GM Forest Trees. Trends Plant Sci. 2016 Apr;21(4):283-5.

Pilate, G., Allona,I., Boerjan,W., Déjardin, A., Fladung, M., Gallard, F., Häggman, H., Jansson, S., Van Acker, R. and C. Halpin (2016). Lessons from 25 Years of GM Tree Field Trials in Europe and Prospects for the Future.Springer Science+Business Media Dordrecht. 2016 C. Vettori et al. (eds.), Biosafety of Forest Transgenic Trees, Forestry Sciences 82, DOI 10.1007/978-94-017-7531-1_4 67

Mottiar Y., Vanholme R., Boerjan W., Ralph J. and Mansfield S.D. (2016). Designer lignins: harnessing the plasticity of lignification. Trends Biotechnol., in press.

Beckers B., Op De Beeck M., Weyens N., Van Acker R., Van Montagu M., Boerjan W. and Vangronsveld J. (2016). Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome. Proc. Natl. Acad. Sci. U.S.A Feb 23;113(8):2312-7. doi: 10.1073/pnas.1523264113.

2015

Van den Bosch S., Schutyser W., Vanholme R., Driessen T., Koelewijn S.-F., Renders T., De Meester B., Huijgen W.J.J., Dehaen W., Courtin C.M., Lagraina B., Boerjan W. and Sels B.F. (2015). Reductive lignocellulose fractionation into soluble lignin-derived phenolic monomers and dimers and processable carbohydrate pulps. Energy Environ. Sci. 8, 1748-1763.

Baldacci-Cresp F., Moussawi J., Leplé J.-C., Van Acker R., Kohler A., Candiracci J., Twyffels L., Spokevicius A.V., Bossinger G., Laurans F., Brunel N., Vermeersch M., Boerjan W., El Jaziri M. and Baucher M. (2015). PtaRHE1, a Populus tremula x Populus alba RING-H2 protein of the ATL family, has a regulatory role in secondary phloem fibre development. Plant J. 82, 978-990.

Dima O., Morreel K., Vanholme B., Kim H., Ralph J. and Boerjan W. (2015). Small glycosylated lignin oligomers are stored in Arabidopsis leaf vacuoles. Plant Cell 27, 695-710.

Verlinden M.S., Fichot R., Broeckx L.S., Vanholme B., Boerjan W. and Ceulemans R. (2015). Carbon isotope compositions (δ13C) of leaf, wood and holocellulose differ among genotypes of poplar and between previous land uses in a short-rotation biomass plantation. Plant Cell Environ. 38, 144-156.

2014

Tobimatsu Y., Van de Wouwer D., Allen E., Kumpf R., Vanholme B., Boerjan W. and Ralph J. (2014). A click chemistry strategy for visualization of plant cell wall lignification. Chem. Commun. 50, 12262-12265.

Niculaes C., Morreel K., Kim H., Lu F., McKee L.S., Ivens B., Haustraete J., Vanholme B., De Rycke R., Hertzberg M., Fromm J., Bulone V., Polle A., Ralph J. and Boerjan W. (2014). Phenylcoumaran benzylic ether reductase prevents accumulation of compounds formed under oxidative conditions in poplar xylem. Plant Cell 26, 3775-3791.

Littlewood J., Guo M., Boerjan W. and Murphy R.J. (2014). Bioethanol from poplar: a commercially viable alternative to fossil fuel in the European Union. Biotechnol. Biofuels 7, 113.

Miedes E., Vanholme R., Boerjan W. and Molina A. (2014). The role of the secondary cell walls in plant resistance to pathogens. Front. Plant Sci. 5, 358.

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Morreel K., Saeys Y., Dima O., Lu F., Van de Peer Y., Vanholme R., Ralph J., Vanholme B., and Boerjan W. (2014). Systematic structural characterization of metabolites in Arabidopsis via candidate substrate-product pair networks. Plant Cell 26, 929-945.

Van Acker R., Leplé J.-C., Aerts D., Storme V., Goeminne G., Ivens B., Légée F., Lapierre C., Piens K., Van Montagu M.C.E., Santoro N., Foster C.E., Ralph J., Soetaert W., Pilate G. and Boerjan W. (2014). Improved saccharification and ethanol yield from field-grown transgenic poplar deficient in cinnamoyl-CoA reductase. Proc. Natl. Acad. Sci. USA 111, 845-850.

2013

Tobimatsu Y, Wagner A., Donaldson L., Mitra P., Niculaes C., Dima O., Kim J.I., Anderson N., Loque D., Boerjan W., Chapple C. and Ralph J. (2013). Visualization of plant cell wall lignification using fluorescence-tagged monolignols. Plant J. 76, 357-366.

Vanholme B., Cesarino I., Goeminne G., Kim H., Marroni F., Van Acker R., Vanholme R., Morreel K., Ivens B., Pinosio S., Morgante M., Ralph J., Bastien C. and Boerjan W.(2013). Breeding with rare defective alleles (BRDA): a natural Populus nigra HCT mutant with modified lignin as a case study. New Phytol. 198, 765-776.

Vanholme B., Desmet T., Ronsse F., Rabaey K., Van Breusegem F., De Mey M., Soetaert W. and Boerjan W. (2013). Towards a carbon-negative sustainable bio-based economy. Front. Plant Sci. 4, 174.

2012

Vanholme R., Morreel K., Darrah C., Oyarce P., Grabber, J.H., Ralph, J. and Boerjan W. (2012). Metabolic engineering of novel lignin in biomass crops. New Phytol. 196, 978-1000.

Vanholme R., Storme V., Vanholme B., Sundin L., Christensen, J.H., Goeminne G., Halpin C., Rohde A., Morreel K. and Boerjan W. (2012). A systems biology view of responses to lignin biosynthesis perturbations in Arabidopsis. Plant Cell 24, 3506-3529.

Harfouche A., Meilan R., Kirst M., Morgante M., Boerjan W., Sabatti M. and Scarascia Mugnozza G. (2012). Accelerating the domestication of forest trees in a changing world. Trends Plant Sci. 17, 64-72.

Research on wood technology of poplar and products

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Joris Van Acker (email: Joris.VanAcker@UGent.be)

Li W., Van den Bulcke J., Mannes D., Lehmann E., De Windt I., Dierick M., Van Acker J. (2014). Impact of internal

structure on water-resistance of plywood studied using neutron radiography and X-ray tomography Construction and Building Materials. 73. p.171-179

Van den Bulcke J., De Boever L., De Vetter L., Van Acker J., Verheyen K. (2013). A low-cost tool-chain for

reconstruction of standing trees of selected European hardwood species. Wood Research. 58(2). p.201-216

Verlinden M.S., Broeckx L.S., Van den Bulcke J., Van Acker J., Ceulemans R. (2013). Comparative study of

biomass determinants of 12 poplar (Populus) genotypes in a high-density short-rotation culture. Forest

Ecology and Management. 307. p.101-111 Li W., Van den Bulcke J., De Windt I., Van Loo D., Dierick M., Brabant L., Van Acker J. (2013). Combining

electrical resistance and 3-D X-ray computed tomography for moisture distribution measurements in wood products exposed in dynamic moisture conditions. Building and Environment. 67. p.250-259

Svedström K., Lucenius J., Van den Bulcke J., Van Loo D., Immerzeel P., Suuronen J.-P., Brabant L., Van Acker J.,

Saranpää P., Fagerstedt K., Mellerowicz E., Serima R. (2012). Hierarchical structure of juvenile hybrid aspen xylem revealed using X-ray scattering and microtomography. Trees-Structure and Function. 26(6). p.1793-1804

Van den Bulcke J., De Windt I., Defoirdt N., Van Acker J. (2012). Plywood under the scanner: linking moisture

dynamics and 3D structure. Proceedings IRG Annual Meeting, Doc IRG/WP 12-20491.

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Van den Bulcke J., De Windt I., Defoirdt N., De Smet J., Van Acker J. (2011). Moisture dynamics and fungal susceptibility of plywood. International Biodeterioration & Biodegradation. 65(5). p.708-716

Lettens S., Vandecasteele B., De Vos B., Vansteenkiste D., Verschelde P. (2011). Intra- and inter-annual variation

of Cd, Zn, Mn and Cu in foliage of poplars on contaminated soil. Science of the Total Environment. 409(11). p.2306-2316

De Boever L., Vansteenkiste D., Stevens M., Van Acker J. (2011). Kiln drying of poplar wood at low temperature:

beam distortions in relation to wood density, tension wood occurrence and moisture distribution Wood Research. 56(2). p.245-256

3. Relations with other countries Novel tree breeding strategies

Joris Van Acker

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Joris.VanAcker@UGent.be

The organisations UGent-Woodlab (Ghent University - Laboratory of Wood Technology), INBO (Research Institute for Nature and Forest) and VIB (Flanders Interuniversity Institute for Biotechnology) were all involved in the EU project Noveltree (Novel tree breeding strategies) coordinated by INRA – France. The Belgian research team worked mainly on poplar selection and breeding related topics. The objectives of this international collaborative project were: The challenges facing forest geneticists and tree breeders include recognition of changing demands on forests for a wider range of high value forest products and sustainability of forest ecosystems under climate change. NOVELTREE is designed to enable significant genetic improvement of tree characteristics and forest products properties to satisfy the needs (quality, quantity, sustainability, vulnerability) of the forest-based sector and consumers. NOVELTREE will: i) Provide a list of morphological and physiological traits relevant as selection criteria for pest tolerance, sustainable biomass production, wood properties for present and future use and plastic response to climate change ii) Identify functional allelic polymorphisms for a suite of traits of interest in a post-genomics approach to improve selection efficiency and monitor genetic variation along the selection process iii) Develop high throughput phenotyping and genotyping tools. These new tools will allow earlier genetic evaluation, higher selection intensity, increased accuracy in genetic prediction and better monitoring of genetic diversity along generations iv) Develop novel/improved breeding strategies and demonstrate their efficiency in case studies. Demonstration will focus on model tree species of high economic importance in different European regions: Maritime Pine, Scots Pine, Spruce, and Poplar v) Assess the financial and environmental impacts of genetically improved trees at stand and landscape levels thanks to a multidisciplinary approach and simulation tools vi) Provide tree breeders and forest owners with support decision tools for optimal deployment of improved genetic stocks in both prevailing and future climate, and under risk of pest and disease attacks vii) Provide training in emerging technologies in connection with on-going European projects, disseminate the results to different publics and transfer technology to the forest-based sector. The open access outcome is available through the CORDIS site: http://cordis.europa.eu.

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Designing Trees for the Future

Joris Van Acker

Ghent University (UGent)

Laboratory of Wood Technology (Woodlab)

Coupure Links 653, 9000 Gent, Belgium

Joris.VanAcker@UGent.be

The project Trees4Future (Designing Trees for the Future) is an Integrative European Research Infrastructure project that aims to integrate, develop and improve major forest genetics and forestry research infrastructures. It provides the wider European forestry research community with easy and comprehensive access to currently scattered sources of information (including genetic databanks, forest modelling tools and wood technology labs) and expertise. Both organisations UGent-Woodlab (Ghent University - Laboratory of Wood Technology) and INBO (Research Institute for Nature and Forest) were involved in RTD and TNA (Trans National Access) work packages with again some focus on poplar. Detail on this EU-project being finalized in 2016 are available on the project website: http://www.trees4future.eu/

4. Innovations not included in other sections IV. SUMMARY STATISTICS (Questionnaire)