One of the goals of forest management is to sustain site productivity so that repeated harvests can be undertaken without loss in growth potential. Canada promotes the development of sustainable forest management practices and aims to demonstrate to the public and its international trading partners that Canadian forest practices will maintain and enhance ecosystem conditions and productivity over the long term. These goals are supported by the Canadian Council of Forest Ministers’ (CCFM) Criteria and Indicators of Sustainable Forest Management. Currently there is renewed concern about the long-term effects of harvesting woody materials that have traditionally not been removed from the site for use as a source of bioenergy. All forest harvesting systems leave tree tops and branches distributed across the logged area. In general, stem-only logging leaves greater amounts than full-tree logging, where materials are concentrated in piles at the roadside. This woody material, or slash, is either burned or left to decompose, returning nutrients for to the soil. In the case of full-tree logging however, there is concern that roadside slash piles do not return the nutrients across the site, possibly leading to longterm site degradation. Similarly, if woody material is moved off site to be used for bioenergy, it is important to evaluate whether the resulting loss of nutrients will have long-term consequences on site productivity. These issues are being examined by scientists with the aid of long-term soil productivity studies that have been established throughout the boreal regions of Ontario.