Canadian Forest Service Publications

Can Bioenergy Ash Applications Emulate the Effects of Wildfire on Upland Forest Soil Chemical Properties? 2019. Hannam, K.D.; Fleming, R.L.; Venier, L.; Hazlett, P.W. Soil Science Society of America Journal: 10.2136/sssaj2018.10.0380.

Year: 2019

Issued by: Great Lakes Forestry Centre

Catalog ID: 39873

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.2136/sssaj2018.10.0380.

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Plain Language Summary

As efforts to combat climate change intensify in Canada and around the world, the use of forest biomass to produce energy is expanding rapidly. At the same time, there is an urgent need for environmentally sustainable methods of handling the highly alkaline but nutrient-rich wood ash waste generated during biomass combustion. Currently, bioenergy ash is often landfilled, placing significant pressure on Canada’s waste disposal infrastructure. Given that forest management in Canada is often driven by the ‘emulation of natural disturbance’ paradigm, bioenergy ash could have potential as a management tool for improving wildfire emulation in harvested stands. This study used meta-analysis to examine changes in soil carbon and nitrogen pools, extractable phosphorus, exchangeable calcium and soil pH following wildfires and applications of bioenergy ash on upland forested sites. Both wildfires and bioenergy ash can reduce forest floor C and N pools, but losses of C and N following wildfires are much greater. From the perspective of maintaining soil C and N stocks, therefore, timber harvesting followed by ash application may present benefits when compared to burning by wildfires. Both wildfires and bioenergy ash applications increase extractable P, exchangeable Ca and pH in surface mineral soils. Although bioenergy ash applications can trigger larger increases in available P and pH in surface mineral soils than wildfires, controlling dosage rates could be used to attenuate some of these effects.