bufferstrips for biomass production
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Bufferstrips for biomass production. Ben Christen, University of Aarhus, Denmark. Contents. Background Buffer function and designs Establishment Performance Policy development. Background. Water Framework directive requires ’ good eclogical status’ by 2015/2027 - PowerPoint PPT PresentationTRANSCRIPT
Bufferstripsfor biomass production
Ben Christen, University of Aarhus, Denmark
Contents
• Background• Buffer function and designs • Establishment• Performance• Policy development
Background
• Water Framework directive requires ’good eclogical status’ by 2015/2027
• Danish ’Plans for the aquatic environment III’ aim to further reduce nitrate pollution by 30%
• Bioenergy policy ’Grøn Vækst’ (green growth) opens lake shores and stream banks
• 5000 miles of watercourses• Production potential >100,000 tonnes/a
Buffer design and function
All Buffer Types• N-removal: 30-99%• P-removal: 20-99%• Pesticide removal: 10-
100% mainly dependent on width
Most suitable layout for biomass production identified:3-zone structure with grass, short rotation forestry + undisturbed zone
Grass strip
Function• Slows and spreads runoff• Filters sediment• Resists erosion by rill
flow• Takes up nutrients
during growing season• Denitrification
Production potential• Biomass for bioenergy
(6-16 t/DM/a)• Hay and silage• Pasture for extensive
grazing• Biogas feedstock
Short rotation forestry zone
Function• Infiltration of water
passing through grass strip
• Captures fine sediment• Removes pesticides• Immobilises nutrients• Denitrification
Production potential• Woodchips (5-14
t/DM/a)• Firewood (5-8 m3/a)• Pulpwood• Timber for higher value
uses
Undisturbed zone
Function• Reduces bank erosion• Protects buffer structure
in flood events• Buffers maintenance and
harvest operations in other two zones
• Enhancement of stream ecology (shade, debris)
Production potential• Occasionally timber of
larger dimensions but low quality
Buffer design variants
Fast BioenergyMiscanthus, reed canary grass, willow, alder, poplar
Higher value timberGrass mixture, bird cherry, oak, field maple, hornbeam, lime
Buffer design variants continued
Gentle slopeReed grass or grass mixture, alder, birch, field maple, poplar
10% slopeGrass mixture, birch, field maple, pear, black locust, alder
Buffer design variants - drainage
Drains broken by ditch before reaching buffer stripReed grass, alder, poplar, downey birch, elm
Establishing a productive buffer
Landscape impact projection
Planning
Ditch Grass strip Grey and red alder
Construction – May 2011
Establishment
Performance forecastTree species Latin name Age of max. mean
annual increment a
Max. mean annual increment m3 ha-1
Mean DM wood density kg/m3
Max. mean annual t DM
ha-1
Field Maple Acer campestre L. 15-25 7 750 5,3Sycamore Acer pseudoplatanus L. 30 11 590 6,5
Black Alder Alnus glutinosa L. 15-20 15.5 490 7,6Grey alder Alnus incana L. 12-16 18.5 490 9,1
Green Alder Alnus viridis L. Unknown b 5 570 2,9Silver Birch Betula pendula L. 15-30 11 630 6,9
Downey Birch Betula pubescens L. 15-30 8 680 5,4Hornbeam Carpinus betulus L. 20-30 5 770 3,9
Common Ash Fraxinus Excelsior L. 40-50 7 670 4,7
Poplar hybridsPopulus deltoides L. based
and other hybrids Unknown c 39 410 16
Aspen Populus tremula L. unknown 16 450 7,2
Aspen hybrids Populus tremula L. based unknown 23 450 10,3
Bird Cherry Prunus avium L. 30 9 580 5,2Common pear Pyrus communis L. 10-15 7 680 4,8
Pendunculate OakSessile Oak
Quercus robur L.Quercus petraea L. 40 7 670 4,7
Red oak Quercus rubra L. 25 8 670 5,4Black Locust Robinia pseudoacacia L. 15 11 730 8,0
Willow hybrids Salix viminalis L. based and other hybrids Unknown d 27 520 14,0
Lime Tilia cordata L.Tilia platyphyllos L.
30 11 520 5,7
White Elm Ulmus laevis L. 20-25 7 640 4,5
EconomicsBuffer land use types Overall Overall
In rotation Grass/clover a Pasture SRC SRF b Undisturbed c Energy balance Gross Margin
Production system (% of area): (MJ/ha/yr) (approx. £/ha/yr)
Winter wheat d 100% 150 500
A) High energy yield 30% 35% 35% 104 240
B) High energy yield + drainage ditch 35% 35% 30% 76 245
C) Multipurpose, intermediate slope 30% 55% 15% 66 150
D) Multipurpose, pronounced slope 50% 25% 25% 48 200
E) Extensive, steep slope 20% 70% 10% 74 130
F) Extensive, slope independent 70% 20% 10% 53 265
G) Woodland, slope independent 90% 10% 83 76
Key figures:
Dry matter yield (t DM/ha/yr) 10 8 5 9 6 0
Energy yield (MJ/ha/yr)e 170 90 55 150 100 0
Energy input (MJ/ha/yr) 20 14 5 10 8 0
Energy Balance (MJ/ha/yr) 150 76 50 140 92 0
Gross margin (DKK/ha/yr) 4500 4000 3000 1500 750 0
Policy development:Fuzzy Cognitive Mapping (FCM)• Procedure to involve
different stakeholders in a research or management process
• Method to extract, depict and analyze different kinds of knowledge
• Way to put academic, regulatory and practical knowledge on equal footing in an expert network
FCM-how-toExample question: Why do tourists come to Scotland and
how does that affect rural development?
Concepts
-pristine wilderness-wildlife-salmon fishing-grouse moor management-golf courses-forestry-rural employment-transport infrastructure-…
Pristine wilderness
Wildlife
Salmon fishing
Golf courses
Grouse moor management
Forestry
Rural employment
Transport infrastructure
An expert networkfrom the CREW Workshop, 03.11.11
Policy impacts derived