The harmful effect of clearcutting on Canada's environment is that it causes erosion. Clearcutting refers to the practice of cutting down all trees in an area, leaving it bald. When this happens, the roots of the trees, which help hold the soil in place, are removed. As a result, when it rains or when there are strong winds, the topsoil gets washed or blown away. This erosion can lead to many negative consequences, including the loss of fertile soil, decrease in biodiversity, and disruptions in ecosystems. It can also cause sedimentation in rivers and streams, which can harm aquatic life and change the flow of rivers. In addition, clearcutting can lead to toxic waste seeping into the groundwater as well as pollution of farmland. To learn more about the harmful effects of clearcutting, you can refer to scientific studies, academic articles, or reports from reputable environmental organizations.