Study Shows Wood Ash Recycling Could Help Muskoka’s Soil And Lakes

Photo courtesy of Sam Forson

A residential wood ash recycling program could restore calcium levels in Muskoka’s soil and lakes to help replenish crayfish and maple sap in the region, according to a study released on March 28.

The study found that residential wood ash, a common household waste from wood-burning fireplaces and wood-fired ovens, contains many nutrients necessary for restoring growth, including about 30 per cent calcium. Calcium in soil and lakes is important for the growth of plants and animals. The levels of calcium across central Ontario is declining due to years of acid rain and it could take centuries for the calcium to rebuild on its own, according to the research. Researchers determined that adding controlled doses of cold residential wood ash to the watershed of Muskoka’s forests could help address calcium decline and boost forest growth.

“Calcium is an essential nutrient for all living things,” said Norman Yan, a professor of biology at York University, who co-led the study. “When you suffer from low calcium, you get osteoporosis and the ecosystem can suffer from osteoporosis as well. Many scientists have called this calcium decline problem ecological osteoporosis.”

Adding wood ash to watershed soils could also help the region’s crayfish stock, water quality, seedling regeneration and production of sap in sugar maple trees. The second phase of the research is AshMuskoka, a three-year pilot project looking to be Canada’s first residential wood ash recycling program.

The project team launched in January and is looking for 200 homeowners to donate their wood ash. In the fall, researchers will conduct small-scale experiments to test dosages, develop tools and find the benefits and harms of wood ash additions. The first test site will be three sugar bushes in Muskoka to see if the doses will restore the bushes to good health and yield maple sap.

“Lack of calcium has slowed the growth, reproduction and development of trees in Muskoka’s forests,” said Yan, who also acts as chair of Friends of the Muskoka Watershed, a nonprofit environmental group.

Forest programs using industrial wood ash exist in parts of Europe like Sweden, but the use of the non-industrial residential wood ash has not been researched and tested until now, said study co-author Shakira Azan, a former post-doctoral biology student and research associate at York University. Azan is also an environmental project lead at Friends of the Muskoka Watershed.

“A lot of people in Muskoka burn wood for heat and some send it to the landfill so, by collecting and recycling their wood ash, we are diverting waste from landfills,” said Azan.

Friends of the Muskoka Watershed is working on the project with nine Canadian partners including Trent University, University of Victoria, Laurentian University, Ontario Maple Syrup Producers Association and York University’s Learning for a Sustainable Future.

To learn more about the study, click here.


  1. And there we have it! A natural phenomenon! Bye product of wood burning to help our soils and lakes! I have always spread my wood ashes on my garden and compost, it introduces lime and calcium back into the soil! I used it on my drive way for traction! No salt no contamination! Many year ago bush fires where allowed to burn out natural in that we did not put them out! The run off went into the soil then into the creeks then into our lakes! Mother Nature is fine, we just mess with her! We don’t need any million dollar studies here, just dump your ashes and I mean cold ashes close to water ways and she will get it done!


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