Looking to the Past for New Ways to Build Sustainability into Wetland Road Crossings

Since the early days of Canada's timber trade, foresters have used "corduroy roads." By laying logs down side by side-giving the appearance of corduroy fabric-they built paths over wet areas, providing bearing capacity of the road surface while allowing the water to flow through.

Forestry roads and poorly constructed water crossings can often interrupt the natural flow of water and the nutrients it carries. In the winter, water flowing through crossings can freeze, blocking the passage of water and creating a build-up of ice on top of the road bed. During the spring melt this ice dam can cause roads and crossings to wash out, creating a myriad of problems for foresters. The Sustainable Forestry Initiative^® (SFI) was eager to support an environmental research project designed to develop and test new crossing techniques for forest roads that intersect with wetland environments. SFI partnered with Ducks Unlimited Canada and SFI program participants LP Canada Ltd., Weyerhaeuser and Spruce Products Ltd.

Ducks Unlimited Canada shared their wetland expertise with forestry professionals to plan and build roads in ways that conserve Canada's critical boreal forest wetland ecosystems. The project focused on boreal forest wetlands in Manitoba and Saskatchewan. Ducks Unlimited Canada worked with engineers from FPInnovations, a nonprofit forest research center in Canada, and forest industry partners to come up with best practices for the construction of resource road wetland crossings.

After many workshops and field trips that focused on understanding wetland hydrology and construction best management practices for forestry roads and crossings that best conserve boreal wetlands, Ducks Unlimited Canada and its forestry partners decided to reinvent the corduroy road crossing.

First, it was important to determine the type of wetland the company would have to cross in order to access timber. For instance, water in bogs is stagnant; in swamps, water flow fluctuates; and water can flow very slowly in fen wetland types. Depending on the wetland type and anticipated water flows, one or several culverts are added to increase water flow capacity and geotextile fabric is used to provide for roadbed separation and support. The root mats and stumps are left intact to further stabilize the road bed. Fabric is placed over the corduroy prior to placing the road gravel to prevent dirt from plugging the corduroy or entering the water. Although the basic crossing design remains the same, minor adjustments are made depending on the wetland type and anticipated flow dynamics of the wetland being crossed. The result is almost like a suspended road that allows water to flow through.

In 2014, the partners produced a wetland field guide and operational handbook that allows foresters to build better roads in the boreal. It helps them classify wetlands and contains construction schematics. Armed with this information, foresters can access timber while at the same time leaving the wetlands intact. Supported with funding from the SFI, the wetland field guide and handbook for forest road wetland crossings are documents that help resource managers identify wetlands in the field and provide practical guidance on how to cross different wetland types.

The project is an excellent example of why SFI launched the conservation grant program in 2010; it brings together conservation and forest engineering expertise, fosters collaboration, and builds knowledge to improve practices and protect special areas. LP Canada Ltd.'s support and continued partnership helps ensure the continued success of these objectives. This project is one of more than 60 SFI Conservation and Community Partnership grants awarded since 2010. Since then, SFI has provided more than 1 $.9 million to foster research and to pilot efforts to better inform future decisions about our forests. When leveraged with project partner contributions, that total investment exceeds 7 $.1 million.

The research, which began in 2011, is now being expanded to a national scale. This project will provide information on forest resource roads and wetland crossings in order to influence best practices on millions of acres of forestland certified to the SFI standard across Canada and the United States.