Carbon stocks and flows in native forests and harvested wood products in SE Australia
This research assessed the greenhouse gas (GHG) balance of native forests managed for multiple use (“production”) and conservation only in New South Wales and Victoria. It considered all the key elements of the carbon (C) cycle in forests and in harvested wood products (HWP), including carbon storage in HWPs in landfills and product substitution impacts (for HWP and use of biomass for bioenergy). When determining the climate impacts of any industry sector, it is important to adopt a true life cycle assessment approach, that takes into account all relevant emissions and C removals; i.e. what the atmosphere actually sees. The research introduced a new model (“ForestHWP”), a tool designed to capture all key elements of the C pools in forests and HWP, allowing immediate integration of parameters and running of simulations that allow for the inclusion of repeated disturbance events (e.g. harvest and fire). In addition to GHG implications, the study considered the socio-economic implications of native forest management, which are often ignored in greenhouse balance studies of native forestry.
The key conclusion of the research is that the relative differences in the GHG balance of production and conservation scenarios do not warrant policies that aim to halt native forest management for wood production. When industry value-added benefits and carbon abatement benefits were added together, the production management scenarios generated much higher values than the conservation management scenarios. This result was independent of the carbon price (low, medium or high).
There is considerable room however for improvement in the GHG outcomes of managing for production. These opportunities could be realised in the forest, in the processing of wood products and in diverting materials to different uses at the end of the life of wood products. The project demonstrated that one of the ways to enhance the GHG outcomes of production forestry is via the increased use of biomass for bioenergy. Currently the majority of forest harvest residues results are burnt or decay over time, with no GHG benefit. Increased use of forest and sawmill residues for renewable energy generation typically displaces the use of fossil fuels, resulting in a net GHG benefit.