Canada's Total Electricity Generation in 2012
= 616 TWh
Why wood ash?
Biomass/ash in Canada/Ontario
Generation source by % shown
Coal
Natural Gas
Biomass 1.4
Hydro 61.2
Other
3.4
Soil chemical properties following wood
ash applications after biomass harvesting
in the boreal forest
Coal 9.5
Nuclear Power 14.5
Oil / Others 1.7
Oil / Others
Nuclear Power
Hydro
Wind 1.8
Biomass
Solar 0.1
Tidal 0.1
Wind
Natural Gas 9.8
Solar
Tidal
Non-hydro renewable fastest growing source of generation in Canada
• 2000 - 5 projects (commercial/institutional/district heating)
• 2014 - 200 projects
• Atikokan 205 MW, Thunder Bay 60 MW, Hornepayne 15 MW
Paul Hazlett1, Dave Morris2, Rob Fleming1, Kara Webster1, Bill Peng3, Neal Scott3, Genevieve
Noyce4, Emily Smenderovac4, Nathan Basiliko5, Honghi Tran4, Paul George6, Zoe Lindo6
1
Service, 2 Ontario
(Office of Energy Research and Development, 2014)
3 Queen’s
Canadian Forest
Ministry of Natural Resources and Forestry,
University, 4 University of Toronto, 5 Laurentian University, 6 Western University
Challenges: Ash storage, disposal, usage, handling, transporting, spreading (James et al., 2012)
2002 – 775,000 tons of ash from pulp and paper mills ~ 80% landfilled (Elliot and Mahmood, 2006)
Potential benefits and drawbacks
Potential benefits and drawbacks

nutrient compensation - “recycling of nutrients
should be a fundamental principle in
sustainable forestry” (Saarsalmi et al., 2001)

nutrient compensation - “recycling of nutrients
should be a fundamental principle in
sustainable forestry” (Saarsalmi et al., 2001)

reduce soil and surface water acidification –
amendment of soils depleted of base cations
(Ca, Mg) due to acid rain, “calcium depletion”

reduce soil and surface water acidification –
amendment of soils depleted of base cations
(Ca, Mg) due to acid rain, “calcium depletion”

application to whole-tree and biomass
harvested sites - enhance forest productivity “liming substitute” = increase soil pH

application to whole-tree and biomass
harvested sites - enhance forest productivity “liming substitute” = increase soil pH

impacts on vegetation and soil biota - caustic

soil pH increase, changes in soil N
production/availability, increased N levels in
soil and surface water

heavy metal contamination
Research Questions
Island Lake Biomass Harvest Experiment
In the context of Canadian forests and soils
1. Do wood ash applications increase soil exchangeable cation pools?
2. Do wood ash applications alter N mineralization?
3. Do wood ash applications increase nutrient or metal leaching?
Can wood ash applications be used as a viable forest
management practice

to replace nutrients removed during biomass harvesting

as a fertilizer to increase forest productivity

to emulate natural disturbance in fire dominated ecosystems
40-year-old jack pine
boreal forest
1825 stems/ha, 30 m2/ha
deep glaciofluvial deposit
10 cm forest floor
clearcut full-tree biomass harvest
1
0, 0.7, 1.4, 2.8, 5.6 Mg ash/ha; 25m X 25m plots; 4 replicates;
equivalent to 0 (full-tree), 50, 100, 200, 400 kg Ca/ha
Sampling
Bottom ash
pH 10.2
LOI 30%
soils resampled 3-years after ash application
porous cup lysimeters installed at 30, 50 and
100 cm depth at time of ash applications sampled once a month, more frequently
during snowmelt and wet fall periods
N mineralization using closed core method growing season - 1-year after ash application
Results: Exchangeable cation pools
Results: Metal leaching
Results: N mineralization
Results: nutrient leaching
Cd
As
Response ratios
Years 1 to 3 after ash addition
2
Conclusions
Thank you
 no increase in forest floor exchangeable cation pools 3 years after ash
application – some indication of 0-10 cm mineral soil increase at the highest
application level - added 400, 25 and 82 kg/ha respectively Ca, Mg, K
 increase in forest floor pH 1 year after application at the two highest
application levels and maintained at 3 years after application. No increase
in mineral soil pH
 no statistically significant increase in N mineralization - decreased
immobilization with ash application
 no effect on nitrogen or heavy metal leaching
 soil chemical properties, soil solution are two of the elements of broader
ongoing assessments – seedling growth, foliar nutrition, ground vegetation,
heterotrophic respiration, biodiversity measurements (bacterial, fungal,
nematode community composition and soil meso and macrofauna)
Results: chemical properties of wood ash
Element
pH
LOI (% - kg ha-1)
TN
Island Lake
Sweden SLU
bottom ash
bottom ash
concentration concentration
loading
high
treatment
Ontario
CM1 CM2
concentration
Ontario
Maximum
5-year
loading
Na 1-year
10.2
31.4 - 2512
10.6
0.08 - 4.5
P
0.2 - 10
K
1.5 - 82
4.4
Ca
7.1 - 400
13.0
Mg
0.5 - 25
1.5
S
0.2 - 13
0.1
Fe
1.1
1.3
Mn
0.3
0.7
Al
3.3
2.6
Na
1.5 - 82
1.0
As (mg kg-1 - kg ha-1)
14 - 0.08
Cd
1 – 0.01
2
3 - 34
Co
15 - 0.08
10
34 - 340
2.7
Cr
39 - 0.22
76
210 - 2800
23.3
Cu
120 - 0.67
88
100 - 1700
13.6
Pb
2
41
150 - 1100
9
Mo
0.9
7
200/500
13 - 170
1.4
0.3
4
5
5 - 94
0.8
Ni
17
30
62 - 420
3.6
Se
3 – 0.02
2 - 34
0.3
Zn
135 - 0.76
500 - 4200
33
509
3