Ash program seeks to ‘wake’ forests
Work being done in Muskoka and Haliburton would return calcium to soils and lakes
By Jenn Watt
A legacy of acid rain, falling calcium levels in some forests and lakes has put pressure on the entire ecosystem, slowing the growth of trees and their ability to capture carbon and endangering calcium-rich aquatic lifeforms.
It’s a process Norman Yan, a research scientist and board member of Friends of the Muskoka Watershed, calls “ecological osteoporosis.”
“Every living creature needs calcium … but our watersheds have lost roughly half a tonne of calcium per hectare over the last 70 years because of acid rain,” Yan told lake representatives during the Coalition of Haliburton Property Owners’ Associations meeting on June 8.
“Because of that, calcium, no longer nitrogen, is often limiting the growth of forests on the Canadian Shield in eastern Canada. … The metaphor I use is our forests are asleep in the winter, but they’re now not fully awake in the summer. They’re kind of napping in the summer because they’re limited by calcium. And because lakes conduct calcium from forest soils, calcium levels in lakes are falling in Muskoka by about 25 per cent.”
Although much of the research done on the project has involved Muskoka, data collected for CHA’s recently released Lake Health Report shows that of the 118 Haliburton lake basins, 17 per cent have a “calcium level low enough where calcium rich animals in those lakes are at risk.”
Yan described the problem in terms of a bank account. Deposits made into the account come from the weathering of rock, dust and precipitation, glacial history and human inputs. Withdrawals are made as trees take in the calcium as they grow; when land is cleared; and mostly through acid rain. Although the rain falling today is much less acidic than it was in the 1970s, the damage done has left the region depleted of calcium; a problem that won’t self-correct for hundreds of years, if not longer.
“We can take collective action to solve this problem,” Yan said.
Ash Muskoka received Ontario Trillium Foundation funding to launch Canada’s first non-industrial wood ash recycling program, which is to include the Haliburton Highlands along with Muskoka.
Through the program, volunteers donate the wood ash they would be disposing of anyway, which will then be spread in designated forests, enhancing tree growth and leading to improved levels in adjacent lakes.
“Ash is essentially all of the minerals that were in the soil,” Yan explained. “When you burn firewood, you’re burning off the part of the tree that came from the air and rainwater and largely what’s left behind in the ash is what came from the soil.”
Non-industrial wood ash is about 30 per cent calcium with metal levels below those of industrial wood ash. Yan said 300 tonnes of wood ash is produced in Muskoka from private citizens, which is enough for the preliminary stages of the project.
“It should allow sugar bushes to be healthier. It should increase carbon capture by forests by as much as 50 per cent. And if we figure out the right doses, the trees will be OK and there will be enough calcium left over for the lakes. And we hope to develop what would then be a novel recycling program for Canada with Muskoka and hopefully you guys showing the way once again,” he said.
The project will determine what doses of ash are needed and prove their benefits in three sugar bushes at first. The goal is to then take that knowledge and apply it to a 10 to 15 hectare catchment using larger volumes of ash, going on to foster ash recycling in Parry Sound and Haliburton.
There have been challenges along the way. Yan said they’ve been looking into how to engage the public and ensure there is follow-through on ash donation. Education also must be done for those donating ash to ensure it’s clean, new and dry.
In Haliburton, CHA has been a partner, with chair Paul MacInnes serving on the stakeholder advisory committee.
“Ecological osteoporosis is the most widespread problem in Muskoka and we now know it affects 17 per cent of the lakes in Haliburton,” Yan concluded. “So, if that is enough of a concern to you collectively ... then I think we can work together to help solve this problem.”