DOE OSTI2016
The environmental sustainability of forest biomass procurement needs to be well understood, as the capacity of ecosystems to provide biomass without negative impacts on ecological functioning limits the biomass potential. Emerging bioenergy markets typically first take advantage of secondary residue streams of various wood processing industries and tertiary end-of-life residues. The use of these secondary and tertiary wood resources is not likely to compromise the environmental sustainability of forests. When these resources in any region become scarce or fully utilized, primary residues (i.e., by-products of forestry harvesting operations and silvicultural practices) such as branches, tops, and non-merchantable trees become increasingly targeted as feedstock sources. Forest biomass procurement in the boreal and temperate biomes should therefore not be analyzed as a stand-alone activity, but rather as an intensification of land use and of forest management, in which tree parts and trees are harvested in addition to conventional forest product fractions. Thus, principles of protection and sustainability should remain the same whether forests are managed for conventional forest products only or also for biomass for energy. Some modifications may be needed to properly identify and find mitigation strategies for sensitive conditions where field evidence suggests that the incremental removal of biomass or other forms of intensive management may not be sustainable. Silvicultural practices such as fertilization, competition control, and soil preparation are options to manage the microenvironment, tree growing conditions, and prevent or mitigate negative impacts. Moreover, landscape management regulations should be put in place to ensure that sufficient biodiversity-important features such as dead wood, aging stands, corridors, etc. are preserved. Special attention should then be directed to trees and stands with high biodiversity values or those important for maintaining ecosystem services which, without a bioenergy market, would have been left uncut. Applying the concept of adaptive forest management, ecological monitoring following harvesting operations, scientific field testing and modeling should be combined to produce better knowledge that could help improve practices. The forestry sector needs to start adapting to a future situation where it is expected to provide conventional forest products, biomaterials and bioenergy. To achieve this, good governance mechanisms such as landscape-level land use planning and science-based improvements of practices will become increasingly important to ensure sustainable forest product supply chains.