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ICFR Central Regional Field Day Page | 2 © ICFR 2015

ICFR Central Regional Interest Group Field Day Date: 25th February 2015 Venue: Iswepe Club, Iswepe, Piet Retief Time: 08h00 for 08h30

PROGRAMME

Time Topic Speaker

08h00-08h30 Tea & Coffee

08h30-08h40 Welcome Johan Nel (TWK), Regional Chairperson

Indoor Presentations

08h40-09h05 Opportunities for further improvement in timber and bark yield for the wattle industry Dr Julian Chan (ICFR)

09h05-09h25 An update on pests and diseases of plantation forestry Izette Greyling (FABI)

09h25-09h45 Measuring the impacts of wattle rust on the productivity of black wattle (Acacia mearnsii) in the KwaZulu-Natal Midlands Thobile Mbatha (ICFR)

09h45-10h10 Eucalyptus grandis x Eucalyptus macarthurii hybrids in South African forestry Joel Cele (ICFR)

10h10-10h40 TEA

10h40-11h05 Multisite nutrient depletion trials Dr Steven Dovey (ICFR)

11h05-11h30 Results from long-term wattle fertiliser trial at Bloemendal (6th rotation results) Dr Louis Titshall (ICFR)

11h30-11h55 To grow pine as a long rotation or as a short rotation crop Graham Rusk (FES)

Field Visits

11h55-13h30 Visit to frost tolerant ICFR wattle trials Dr Julian Chan (ICFR)

13h30-14h15 Lunch at Iswepe Club

14h15-15h30 Visit to Iswepe Mill


Opportunities for further improvement in timber

and bark yield for the wattle industry*

Julian Moreno Chan [email protected]

Institute for Commercial Forestry Research, P.O. Box 100281, Scottsville, Pietermaritzburg, 3209

Acacia mearnsii De Wild (black wattle) is an important plantation species for tannin production and

woodchip exports in South Africa. About 45 000 tons of bark extract are produced annually of which the

majority is exported for leather products and wood adhesives. International demand, however, has

remained static over the last two decades due to intense competition from synthetic tannins and the effect

of oil-prices on oil-based adhesives. The species offers important economic advantages for pulp

production (higher wood density and pulp yield, which translate into higher digester productivity and

factory output), as well as superior long-distance stowage in vessels. These factors make A. mearnsii a

sought-after species and have ensured a sustained demand for wattle woodchips in the Japanese

market, and today, continues to attract new customers in emerging markets (China and India). Total black

wattle woodchip exports in 2013 were 800 000 BDMT.

For a number of reasons, efforts are concentrated on increasing productivity from the existing plantation

resource in South Africa:

1) Reductions in land base (20 000 ha of corporate land lost in the period 2003-2013),

2) Changes in species due to risk (frost and new pest and diseases),

3) Current timber yields are below site potential, and

4) Superior timber yields from international competitors.

This presentation discusses the strengths and weaknesses of black wattle in the international woodchip

and pulp markets, the opportunities to increase current yields, and poses the question of whether the

wattle growers are realising the potential of the current improved stock. These issues are discussed in the

context of the A. mearnsii breeding programme, highlighting priorities and what should be done.

* A good part of information for this presentation was taken from the paper: Moreno Chan, Day, Feely, Thompson, Little, Norris (2015). Acacia mearnsii industry overview: current status, key research and development issues. Southern Forests Journal <in press>


An update on pests and diseases of plantation forestry

Izette Greyling1, Jolanda Roux, Alistair McTaggert and Brett Hurley [email protected]

Tree Protection Co-operative Programme (TPCP), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa

The impact that pests and diseases have on the forestry industry has been increasingly evident over the

past year. The appearance of two new insect pests (Ophelimus maskelii and Spondyliaspis plicatuloides),

the outbreak of a rust disease on A. mearnsii, the range expansion of pitch canker of mature trees, and

the Cossid moth (Coryphodema tristis), have contributed to the ever increasing challenge of forest

management. All is not doom and gloom though, as the year also saw the anniversaries (and continued

releases) of Selitrichodes neseri, the biocontrol agent for Leptocybe invasa, and Cleruchoides noackii, the

biocontrol agent for Thaumastocoris peregrinus. In addition, the BiCEP (Biological Control of Eucalyptus

Pests) programme, an international collaboration between FSA (FABI), Australia and Brazil to share

knowledge and biological control agents for major eucalypt pests, continues to evolve. Research into the

use of Psyllaephagus bliteus as a potential biocontol agent for Glycaspis brimblecombei is ongoing in the

FABI Biocontrol Centre at the University of Pretoria.

Management of tree pests and pathogens requires a team effort and participation of the whole industry.

Farmers and foresters are encouraged to report any tree health problems to the TPCP. This will facilitate

the detection of new problems and assist in monitoring established pests and pathogens.

____________________________________________________________________________________

For any pest and/or disease information please contact:

Jolanda Roux (Extension and Diagnostics) – 082 909 3202, [email protected]

Izette Greyling (Extension and Diagnostics) – 083 269 1983, [email protected]

Darryl Herron (Diagnostic Clinic) – [email protected]

Brett Hurley (Insect Biocontrol) – [email protected]

Jeff Garnas (Entomology) – [email protected]

____________________________________________________________________________________

We also host a list server where information regarding various aspects related to tree health are shared.

If you would like to subscribe to Treehealthnet, please contact Wilhelm de Beer at

[email protected] or any of the above listed people for assistance.

____________________________________________________________________________________


Measuring the impacts of wattle rust on the productivity of black wattle

(Acacia mearnsii) in the KwaZulu-Natal Midlands

Thobile Mbatha and Andrew Morris [email protected]

Institute for Commercial Forestry Research, P.O. Box 100281, Scottsville, Pietermaritzburg, 3209 A new disease was discovered in the 2012 in the wattle plantations near Eston and has been spreading

in KwaZulu-Natal and infecting trees of all ages. The disease is of Uromycladium rust fungi, and the

species is still under identification by the Forestry and Agricultural Biotechnology Institute, (FABI,

University of Pretoria). These fungi have a complex lifecycle that can involve the formation of up to three

types of fruiting bodies and four spore types. The complexity in the lifecycle of these fungi makes it

challenging to identify the species name and to better understand the pathogen’s biology. A better

understanding of the pathogen’s biology, epidemiology, and impact on productivity will be crucial in

effectively coming up with management strategies for wattle rust. Therefore, a multi-faceted project with

various academic and industry partners, was initiated with the following main aims:

(i) Determine the impact of wattle rust on black wattle growth and productivity;

(ii) Understand the interaction between wattle rust and co-occurring insects and their impact;

(iii) Relate the level of infestations to environmental factors and identify triggers of outbreaks; and

(iv) Provide ground-truthing points for calibration of remote sensing monitoring of the disease

incidence.

This presentation will give feedback on the trial in City Forestry. Three exclusion plot trials were

implemented in October 2014 to measure the impact of the pathogen on black wattle growth and

productivity. Fungicide (mixture of azoxystrobin and difenoconazole), insecticide (cypermethrin) or

combination of both, were applied to exclude any pest or pathogen in the trials. iButtons are being used to

measure temperature and relative humidity in the trials. Plant growth parameters (i.e. tree height and

ground line diameter) and weekly disease assessments are being measured in each trial. New spores

were observed after a period of cool and high relative humidity which is common for rust fungi

development. These need to be transported to encounter compatible mating types, in the case of wheat

rust, and are carried by insects (Schumann & Leonard, 2000). The new wattle rust infection was followed

by an increasing number of insects in the trial, most abundantly being the Melolonthinae: Hopliini. Under

similar environmental conditions stem infections were observed. At this stage, there are no significant

differences in terms of tree growth. However, considerable defoliation was observed in the trees which

later will have an impact on growth of the trees. It is therefore, important to continue with the current

observations as they are contributing to our understanding of the pathogen’s biology, epidemiology and

its impact on productivity, support to ultimately developing an integrated management strategy for wattle

rust.

Reference:

Schumann GL, Leonard KJ. 2000. Stem rust of wheat (black rust). The Plant Health Instructor. DOI:

10.1094/PHI-I-2000-0721-01


Eucalyptus grandis x Eucalyptus macarthurii hybrids

in South African forestry

Joel Cele1 and Tammy Swain [email protected]


Global predictions for the next 50-100 years foresee an increase in temperature, increase or decrease in

rainfall, and increase in frequency and intensity of extreme events. Therefore, the development of hybrids

that can tolerate these events is a priority. Eucalyptus grandis is a species of major importance for

plantations with approximately 340 000 ha grown in South Africa. The species has vigorous growth,

coppices well and has good rooting ability, stem form and pulping properties, but average to low wood

density and is highly prone to frost damage. Eucalyptus macarthurii is one of the few cold and frost

tolerant eucalypt species commercially planted on colder, high altitude and low productivity sites in South

Africa. Hybrids were developed by crossing E. macarthurii pollen (ex ICFR) onto E. grandis selections (ex

CSIR), and hedges were established in White River. Cuttings were made to establish clone testing trials

at five sites; Panbult, Wyntoun, Potgieterskeus, Piet Retief and Shiselweni (Swaziland).

Growth characteristics (diameter at breast height and height) were evaluated in the E. grandis x

E. macarthurii clones and controls, and basal area calculated. The top performing clones were sampled for

pulp yield and basic density. Results showed that there were clones that performed better than, or equal to,

the pure species controls for diameter, basal area and height at the sites. The basic density of the top

E. grandis x E. macarthurii clones was higher than that of the E. grandis control, at sites where it was

planted. The pulp yield of the selected top clones was higher than that of both E. grandis and E. macarthurii,

but comparable to that of E. nitens and E. dunnii. Twenty clones were selected, based on diameter at breast

height, height and pulp yield, for further testing as having commercial potential for growth on the more

temperate sites of the summer rainfall regions of South Africa.

These clones are currently being rooted in Piet Retief and at the ICFR nursery in Pietermaritzburg for the

establishment of hedges. To date, hedges of 18 of the top 20 performing E. grandis x E. macarthurii clones

have been established at both nurseries.

• Hedges were screened for Leptocybe invasa susceptibility and large variation between the clones

was found. Coppice of the original trials was assessed for the presence of L. invasa three times

during 2014, but there were no signs of damage by the pest.

• Cuttings have been rooted, and two sites chosen, for the establishment of 2nd phase clonal trials

early in 2015.


Multisite nutrient depletion trials

Steven Dovey [email protected]


Site nutrient supply must be maintained if the productivity of successive rotations is to be sustained.

Nutrients are supplied to trees from soil reserves that are at risk of becoming depleted through continuous

nutrient removals associated with harvesting and residue management. The ability of forestry soils to

resist and recover from nutrient loss is poorly understood. There is no link between laboratory-determined

nutrient pool size estimates, soil supply potential and the ability of trees to take up and efficiently utilise

nutrients. The ability of sites to naturally recover or be ameliorated is also poorly understood.

A research project was initiated in 2013 that aims to develop knowledge on the nutrient loss that key soils

can withstand until tree growth becomes nutrient limited. Nutrient removal is carried out through intensive

biomass removal. The aim is to induce nutrient-related growth decline in the tree crop on soils derived

from six major parent materials and to relate the decline to laboratory based indicators of soil nutrient

supply. A second phase of this project will be to test the ability for soils to recover naturally or through

fertilisation.

Six research trials were initiated between 2012 and 2014. These are situated on soils with properties to

create a range in risk of soil fertility decline (Table 1 ). The studies utilise a combination of high density

planting, heavy coppicing and annual harvesting and complete residue/litter (forest floor) removal to

induce rapid soil nutrient loss. Nutrient removal through complete tree and residue removal is compared

with treatments that retain or replace nutrients (namely residue retention and fertilisation). After the lower

nutrient supply limits have been detected or identified, the field trials will be operationally re-planted at

conventional spacing to test the ability of each site and soil to recover from nutrient depletion naturally or

through fertilisation.

A treatment-related growth response has already been detected at the first site (NDS2-Windyhill) after

two harvest cycles. A reduction in tree growth and depression of top-soil nutrient status has occurred with

residue and litter removal. Fertilisation and residue retention has maintained tree growth rates.


Table 1: General site and 0 - 20 cm soil information for the six nutrient depletion study (NDS) sites

Trial NDS1 NDS2 NDS3 NDS4 NDS5 NDS6

Planted 2013 2012 2014 2015 2015 2015

Lithology Aeolian sand

Natal Group sandstone

Aeolian sand Gabbro Granite Shale

Site Dukuduku Windyhill Kwambo (SQF) Glen Eland

Glen Eland Clan

Region Zululand Midlands Zululand Central Central Midlands

Species Egxu Egxu Egxu Egxn Egxn Egxu

MAP (mm) 919 840 1260 884 926 1015

MAT (°C) 21.8 18 21.9 14.8 14.8 18.1

Altitude (m) 47 800 24 1472 1481 788

Silt % 3.0 28.1 3.3 20.4 12.3 nd

Clay % 4.1 17.3 5.9 31.5 21.5 nd

Sand % 92.9 54.7 90.9 48.1 66.2 nd

pH (KCl) 4.4 4.0 3.8 4.1 3.9 3.6

pH(H2O) 5.2 4.8 4.4 4.1 4.8 3.9

N % 0.08 0.40 nd 0.22 0.17 0.51

P (ppm) 3.88 25.39 2.52 2.83 3.71 6.51

K+ cmolc kg-1 0.05 0.19 0.04 0.09 0.15 0.20

Ca2+ cmolc kg-1 0.90 2.27 0.26 0.46 0.88 0.60

Mg2+ cmolc kg-1 0.27 0.94 0.17 0.09 0.23 0.27

Na+ cmolc kg-1 0.04 0.11 0.05 0.04 0.02 0.06

S-value cmolc kg-1 1.26 3.50 0.52 0.59 1.29 1.14

OC (WB) % 0.47 4.65 1.03 3.20 2.28 8.35

Ex.Acid cmolc kg-1 0.20 1.50 0.52 1.48 0.93 7.16

nd = no data (awaiting lab results)


Results from long-term wattle fertiliser trial at Bloemendal (6th rotation results)

Louis Titshall [email protected]

Institute for Commercial Forestry Research, P.O. Box 100281, Scottsville, Pietermaritzburg, 3209 Project Team: Greg Fuller, Michael Buthelezi, Nkosinathi Kaptein

Introduction

In the late 1940’s a number of factorial fertiliser experiments were implemented to help develop and refine

fertiliser application recommendations for wattle production. In most cases combinations of nitrogen,

phosphorus, potassium and lime were tested. One of the trials (C2 at Bloemendal) was reimplemented for

a further five rotations. The 6th rotation was felled in early 2014 and this presentation provides some of

the early results of various growth parameters assessed.

Experimental overview

34 factorial arranged in a quasi-latin square confounded in nine rows by nine columns. Table 1 presents a

summary of historical fertiliser regimes used.

Table 1: Overview of fertiliser regimes used for each rotation of the long-term wattle fertiliser trial at Bloemendal.

Rotation 1 to 3 Rotation 4 Rotation 5 Rotation 6

kg ha -1 (g tree -1) Nitrogen (as Ammonium sulphate)

0, 25, 50 (0, 10.5, 21) None

Phosphorus (as Single Super Phosphate)

0, 20, 40 (0, 8, 16) None

Potassium (as KCl) 0, 60, 120 (0, 12.5, 25) 0, 30, 60 (0, 6, 12) None

Lime 0, 5.6, 11.2 (as agricultural lime)

0, 5.6, 11.2 (as dolomitic lime)

None None

Planting notes Line sowing, thinned to ± 1400

Seedling planted in pits, thinned to ± 1500

Seedling planted in pits, never thinned (± 2400)

Dates R1: 1951 to 1961 R2: 1961 to 1971 R3:1971 to 1982

1982 - 1992 1992 - 2003 2003 - 2014

Variates assessed

• DBH (converted to basal area), total height, volume, stocking, wet bark yield

• Soil samples and bark samples for analysis also collected but not reported here


Results

• No significant residual interaction effects (p > 0.05)

• No significant main effects of N or K (p > 0.05)

• Some significant main effects of P and Lime (p < 0.05)

o Positive P responses for BA, height, volume

o Negative lime response for BA, volume, stocking and wet bark yield

Some Preliminary Thoughts

• Liming negatively affects production for extended periods – Do not lime wattle plantations.

• Evidence of residual P – may offer opportunity to lower P fertilisation rates in the future.

• Past and current results do not indicate any benefit to nitrogen fertiliser.

• Re-application of potassium may be necessary to main nutrient balance.

Acknowledgements

SAWGU for funding,

Gary Behn and staff for land and operational assistance, past and current ICFR staff involved with trial.


To grow pine as a long rotation or as a short rotation crop

Graham Rusk [email protected]

Forestry Economics Services

Few of us can plant pine trees to grow on a long rotation of 25 to 30 years and see the results of our

efforts by clearfelling the crop. For many of us that pleasure will be left to our sons and daughters who

inherit the farms, just as we have benefitted from the planting of these long rotation crops by our fathers.

Why plant pine to be managed on a long rotation? Why not plant pine on a short rotation and get our

money back after 15 years? Most of us would see that day. The only problem is that you will probably

only get back the money put into the crop those many years ago with nothing to contribute to your wealth.

This situation has shown up consistently for many years in our monitoring of short rotation pine crops.

The prices for pulpwood do not support the usually high transport costs to distant mills. Pulp prices have

improved slightly quicker over the past few years in order to combat the emerging competition from the

boxwood market but it is still insufficient to encourage investing in a short rotation pine crop.

It appears that the major consumers of pine pulpwood; Sappi and Mondi, are changing their processing

plants to take in less pine and more gum. This will almost demolish the short rotation pine market (about

93% of the crop sold as pulpwood) and it will also create problems for the pine sawlog producers (about

8.5% of the crop sold as pulpwood).

The following table shows the Financial Analysis of both long and short rotations of pine in this Highveld

area for the two years; 2011 and 2012. This Financial Analysis represents a plantation in cycle with one

25th (long rotation) or one 15th (short rotation) of the area being clearfelled and replanted each year. Then

only could all the income for the year be added and all the expenses subtracted to give a profit or loss for

the year like a crop farmer.

Do we ever reach such a perfect stage in reality with fires, expansion and other situations putting

plantations out of cycle? No, or very seldom. So how do we know whether a long-term project such as

timber growing is profitable? This Financial Analysis page puts together the prices received for the

different products sold in 2011 or 2012 and the current annualised costs of performing the various forestry

operations in 2011 or 2012, then multiplies this by the sustainable, marketable MAI (cubic

metres/ha/year) to provide an annual profit per hectare of plantation before tax, bond interest, loan

repayments, capital expenditure and income tax.

The annualised profit potential of the long and short rotation crops is shown in line 2.22 of the Financial

Analysis. This tells its own story and should make one hesitant to invest in a pine crop to be grown and

managed on a short rotation.


FORESTRY ECONOMICS SERVICES

MPUMALANGA SOUTHPINE FINANCIAL ANALYSES

LONG ROTATION SHORT ROTATION

2011 2012 2011 2012

1.0 PLANTATION DETAILS

1.1 AVERAGE PLANNED ROTATION AGE Years 25.9 26.3 16.4 16.0

1.2 ACTUAL AGE AT CLEARFELLING Years 26.7 25.6 16.8 16.5

1.3 AVERAGE PLANTATION AGE Years 11.6 12.1 6.9 7.1

1.4 ACTUAL TONS SOLD tons 554 921 559 427 463 045 350 845

2.0 ANNUAL SUSTAINABLE PROFIT PER HECTARE IF M.A.I. IS FELLED AND SOLD

2.1 Timber delivered to Buyer R/ton 455.81 514.34 287.55 314.98

2.2 Timber sold Free on Rail or Depot R/ton 480.74 263.05 - 218.78

2.3 AVERAGE PRICE RECEIVED R/ton 458.97 513.80 287.55 314.93

2.4 Less : Transport costs R/ton 62.21 64.68 130.99 170.02

2.5 NET PRICE ON ROADSIDE R/ton 396.76 449.12 156.56 144.91

2.6 Timber sold on roadside R/ton 487.61 510.08 384.26 405.42

2.7 AVERAGE PRICE ON ROADSIDE R/ton 431.83 479.22 169.14 163.96

2.8 Less : Harvesting costs R/ton 76.26 76.09 65.89 74.22

2.9 NET STANDING PRICE R/ton 355.57 403.13 103.25 89.74

2.10 Standing sales R/ton - - 121.12 108.44

2.11 AVERAGE STANDING PRICE PER TON R/ton 355.57 403.13 103.40 89.94

2.12 Divided by : Conversion Ratio m³/ton 0.94610 0.94224 0.99613 0.99563

2.13 AVERAGE STANDING PRICE PER M³ R/m³ 375.83 427.84 103.80 90.33

2.14 Multiplied by : Sustainable M.A.I. m³/ha/yr 14.71 14.69 14.88 14.88

2.15 ANNUAL STANDING INCOME R/ha 5 526.58 6 284.97 1 544.54 1 344.11

2.16 Add : Sales of other forest products R/ha 8.83 4.43 2.77 3.51

2.17 Less: Establishment costs R/ha 170.45 178.53 204.80 211.92

2.18 Tending costs R/ha 226.03 277.35 160.19 166.56

2.19 Forest Protection costs R/ha 358.56 502.71 358.56 502.71

2.20 GROSS MARGIN R/ha 4 780.37 5 330.81 823.76 466.43

2.21 Less: Overhead costs R/ha 815.46 933.26 815.46 933.26

2.22 ANNUAL PROFIT POTENTIAL IF M.A.I. IS SOLD R/ha 3 964.91 4 397.55 8.30 (466.83)

3.0 EXTENT OF UNDERFELLING (OR OVERFELLING) THI S YEAR RELATIVE TO M.A.I.

3.1 MEAN ANNUAL INCREMENT m³/ha/yr 14.71 14.69 14.88 14.88

3.2 Less : Total Sales this Year m³/ha 10.87 9.81 10.47 10.05

3.3 RELATIVE UNDERFELLING (OVERFELLING) m³/ha 3.83 4.88 4.41 4.83

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