Turkey Lakes Watershed - Forest Soils
Research in a Large-Scale
Environmental Laboratory

Soils at the Turkey Lakes Watershed are naturally acidic. Iron, aluminum and carbon in the lighter coloured layer have been leached to lower layers, causing the reddish colour.

"We found our watershed!" These were the excited words Dr. Ian Morrison heard over the telephone one August evening in 1979. Ian, a Natural Resources Canada (NRCan) research scientist at the Great Lakes Forestry Centre in Sault Ste. Marie, Ontario, had been waiting for this moment for several months. After an exhaustive search, NRCan soil scientist Dr. Neil Foster and forest hydrologist Dr. John Nicolson had found a suitable research site to begin integrated studies on the impacts of acid rain. While their excitement was understandable, none of the men could have realized that their work would become part of a long-term database that would help in understanding emerging environmental issues decades into the future.

"The Turkey Lakes Watershed study originally focused on the effects of acid rain on the forest ecosystem," says Dr. Paul Hazlett, a forest soils scientist at the Great Lakes Forestry Centre. "Over time, the study has expanded to look at the effects of forest harvesting and climate change."

The Turkey Lakes site encompasses about 1000 hectares on the Canadian Shield, about 60 kilometres north of Sault Ste. Marie. Its shallow, acidic soil and mature sugar maple – yellow birch forest is typical of the Algoma region. As an experimental watershed, it allows researchers to link natural and man-made disturbances on the land to responses in streams and lakes.

The ongoing study is a joint partnership among NRCan, Environment Canada and the Department of Fisheries and Oceans, and the initial site selection was based on criteria established by each department. The site was reserved for research use by the Ontario Ministry of Natural Resources and remains exempt from commercial forestry and mineral exploration. A steering committee with representatives from each of the agencies guides the research program at the watershed. From the beginning, the Turkey Lakes Watershed project has been a model for research collaboration.

Early soil science research contributed to the development of the Canada-U.S. Air Quality Agreement in 1991. The research demonstrated the value of emissions controls in helping prevent nutrient loss from soil caused by air pollution, specifically atmospheric sulfates and nitrates. Since that time there has been some recovery in stream and lake chemistry, and though the acid rain issue has faded from the public eye, work continues on measuring the long-term effects on forest growth, soil chemistry and water quality.

During the mid-1990s public interest in the impacts of forestry practices led to the development of the Turkey Lakes Harvesting Impacts Project. Harvesting and site preparation disturb the forest ecosystem and can change the way nutrients and water move through the soil. For example, nitrogen is essential to plant growth and makes up about 80 percent of the air, but can't be used by plants in that form. Nitrogen is released when leaves and trees fall and decompose, and trees take up this nitrogen. Tree removal through harvesting and disruption of tree uptake can upset the natural cycling of nitrogen and cause a loss of soil nutrients. Working with an industrial partner, NRCan scientists looked at the effects of various methods of tree harvesting and shared their results with provincial and forest industry stakeholders. The result was an improved understanding of the immediate and long-term sustainability of different forest management practices.

The chemical cycles that take place in an ecosystem affect its living and non-living components — chemicals are recycled and energy is absorbed and released by air, land and water. Current NRCan soils research at the Turkey Lakes Watershed is focused on the study of these biogeochemical cycles and how forest soils are responding to pollution and changes in climate.

"We now have over 25 years of data from Turkey Lakes, including climate data," says Paul. "Recently, NRCan scientists have been working with university partners to measure the release, or flux, of greenhouse gases (GHGs) from different topographic locations within in the forest."

This work will link soil emissions of carbon dioxide, methane and nitrous oxide to chemical and environmental conditions, and allow prediction of GHG fluxes across the forest landscape under different climates.

The longevity of the Turkey Lakes partnership and the collaboration among governments, industry and academia provide a unique look into how various environmental stressors have affected an entire forest ecosystem. Ongoing support by the Government of Canada has allowed for research across a range of disciplines, which in turn has attracted researchers and funding from outside sources. Projects like Turkey Lakes also provide a way to validate the effectiveness of previous policy decisions and international agreements, and generate scientific knowledge for the development of future policies on clean air and global change.

"The Turkey Lake Watershed provides a long-term benchmark record of climate, forest, soil and water data that researchers can use to address future environmental issues as they evolve," says Paul. "This will help us as we continue to work with our forest partners to develop policies that will help ensure a healthy, sustainable forest."