Bioenergy Opportunities In the Boreal: Assessing Soil/Site Sensitivity to Increased Biomass Removal.

Canada’s boreal forest totals 310 million hectares, representing 77% of the national forest area and accounting for approximately 50% of the annual forest harvest. As demand for traditional forest products has declined in recent years, federal and provincial governments have strived to provide favourable policies to encourage use of a well-developed industrial infrastructure and workforce to produce new fibre-based products. Many such bioenergy projects are aimed at utilizing this skilled labour force, together with forest biomass that from an economic perspective was previously considered waste material.

While operational full-tree logging in the boreal can leave a wide range of biomass residues on site after harvest (5-65 tonnes/ha), forest management and certification regulations state that any removals of this material must only be done while ensuring long-term site productivity and forest health. We examine nutrient removals and retention, and 15-year plantation growth response from Long-Term Soil Productivity (LTSP) sites in the boreal forest of northern Ontario. Sites have coarse textured, nutrient poor mineral soils where long-term soil productivity could be compromised by excessive nutrient depletion through biomass removal. Portions of each site were stem-only and full-tree harvested, and full-tree harvested with forest floor removal. Our objective was to determine indicators that could be used to predict productivity response and therefore be used to develop guidelines for biomass removals.

This presentation will also provide an overview of provincial, national and international initiatives (e.g. research/policy linkages, literature reviews and meta-analysis, and spatial mapping of suitability sites for bioenergy harvesting) that we are involved in and a look forward to a new boreal biomass harvesting initiative. Building on the LTSP design we present a conceptual model and an experimental approach to assess a broader suite of biomass removals and the impact of biological legacy on long-term productivity and biodiversity.