Wood ash recycling in forests: opportunities and challenges...Wood ash use internationally Sweden:...
Transcript of Wood ash recycling in forests: opportunities and challenges...Wood ash use internationally Sweden:...
Wood ash recycling in forests: opportunities and challenges
Paul Hazlett, Kirsten Hannam, Lisa Venier Natural Resources Canada - Canadian Forest Service
Sault Ste. Marie, Ontario Bio-heat Community of Practice Workshop, March 7, 2017
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
• Challenges - certain barriers
• Moving forward
Bioenergy production in Canada
National Energy Board. 2016.
Bioheat projects in Canada
OMECC, 2016.
Wood ash use internationally
Sweden: ‘Ash recycling should be done on sites where extensive amounts of harvesting residues are extracted at some point during the rotation period’ (Swedish
Forest Agency 2008)
Finland: ‘Logging residue can be cleared if the nutrient balance of the forest stand is maintained through the use of ash’ (TAPIO 2010)
United Kingdom: ‘…the removal of brash could be acceptable on all of the high risk soil types provided that the nutrients are replaced through… the application of limestone or wood ash’ (Forestry Commission 2009)
Amelioration of biomass harvested sites with wood ash waste: improving Canadian forest productivity and sustainability through an alternative approach to bioenergy waste management
Partners: Ontario Power Generation, Wood Pellet Association of Canada,
Tembec, CanFor Pulp, J.D. Irving, Resolute Forest Products, MNRF,
FP Innovations
Laurentian U, Lakehead U, U of Toronto, U of Northern British
Columbia, U of Manitoba, U of Quebec, U of Saskatchewan
http://cfs.nrcan.gc.ca/projects/140 (English) http://scf.rncan.gc.ca/projets/140?lang=fr_CA (French)
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
• Challenges - certain barriers
• Moving forward
Canadian bioenergy wood ash chemistry (pH 7 – 14)
Fly ash Bottom ash
Calcium (g/kg) 92 - 248 4 - 211
Magnesium (g/kg)
6 - 29 1 - 33
Potassium (g/kg)
14 - 91 1 - 51
Nitrogen (g/kg) 0.4 - 4 <0.01 - 3
Phosphorus (g/kg)
3 - 11 0.1 - 12
Soil pH and plant nutrient availability
% Sa Si Cl pH
LFH 3.9
Ae 68 26 6 4.0
Bm1 61 31 8 5.0
Bm2 79 16 5 5.2
C 94 2 3 5.3
Brady and Weil, 2002
nutrient compensation - “recycling of nutrients should be a fundamental principle in sustainable forestry” (Saarsalmi et al., 2001)
reduction in soil and surface water acidity - amending soils depleted of base cations (Ca, Mg, K) due to acid rain
fertilization of whole-tree and biomass harvested sites - enhancing forest productivity by raising soil pH
Potential environmental benefits of recycling ash in forests
Wood ash study sites
Number of papers 109
Number of sites 118
Number of countries 14
Biomes Boreal, temperate, Mediterranean
Stand ages Ranging from clearcuts to 100 year old stands
Wood ash studies - Europe
Wood ash studies – North America
Forest Floor pH
Ash granules (Emilsson 2006)
Hardened ash (Emilsson 2006)
Loose ash
Exchangeable calcium
Nutrient Availability
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
- increased soil pH
- increased nutrient availability
= ?
Fly Ash (mg/kg)
Bottom Ash (mg/kg)
Wildfire Ash (mg/kg)
Arsenic 4 - 28 <0.1 - 139 6
Cadmium 2 - 18 0.1 - 8 0.1
Copper 35 - 145 0.1 - 205 6
Lead 3 - 61 0.5 - 369 15
Zinc 389 - 2662 32 - 1504 500
http://www.msnbc.com/msnbc/washington-worst-wildfire-aftermath#slide1
Fire ash data from Maynard et al. 2014. Env. Rev.
Exchangeable calcium
Bioenergy ash application Wildfire and prescribed fire
FOREST FLOOR MINERAL SOIL
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
- effects on nutrient availability similar to wildfire?
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
• Challenges - certain barriers
• Moving forward
• Wood ash - AB • Soil amendment – BC (fly ash) • Waste - BC (bottom ash) • Industrial By-Product - NB • Biosolids - NS • Solid non-hazardous waste; Non-agricultural source material – ON • Fertilizing residual/Liming material – QC • Fertilizer – Canadian Food Inspection Agency • Liming agent - Canadian Food Inspection Agency • Compost - Canadian Council of Ministers of the Environment
(CCME)
In general, the use of wood ash as a soil amendment falls under provincial/territorial jurisdiction…
http://cfs.nrcan.gc.ca/publications/download-pdf/37781 (English) http://cfs.nrcan.gc.ca/publications/download-pdf/37782 (French)
soil pH increase, changes in soil N production/availability, increased N levels in soil and surface water
heavy metal contamination
impacts on vegetation and soil biodiversity - caustic
Potential environmental problems of recycling ash in forests
Ash-specific guidance needed?
• Ash pre-treatment
• Application timing and frequency
• Co-applications (urea; pulp and paper biosolids; lime; biotite)
• Dosage rate
Dosage rate comparisons
Europe Canada Austria 3 Mg/ha/50 years CCME: 200 Mg/ha/45 years
Denmark
0.5-7.5 Mg/ha/10 years Alberta: 45 Mg/ha/lifetime
Lithuania 5-6 Mg/ha/rotation Quebec: 88 Mg/ha/20 years
Sweden 3 Mg/ha/10 years; 6 Mg/ha/rotation
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
• Challenges – certain barriers
- regulatory approval process
- environmental impacts knowledge
- no Canadian guidance specifically for forests
Wood ash recycling in forests: opportunities and challenges
• Context
• Opportunities - possible benefits
• Challenges - certain barriers
• Moving forward
http://cfs.nrcan.gc.ca/projects/140 (English) http://scf.rncan.gc.ca/projets/140?lang=fr_CA (French)
Ash chemistry database Techno-economic analyses Canadian research sites
UNBC – USask – UManitoba – LakeheadU – CFS/MNRF – LaurentianU/UToronto/MNRF - UQAT/TELUQ
AshNet Research Sites AshNet contacts: [email protected] [email protected]