Quantifying the biophysical climate change mitigation potential of Canada's forest sector

Abstract

Abstract. The potential of forests and the forest sector to mitigate greenhouse gas (GHG) emissions is widely recognized, but challenging to quantify at a national scale. Forests and their carbon (C) sequestration potential are affected by management practices, where wood harvesting transfers C out of the forest into products, and subsequent regrowth allows further C sequestration. Here we determine the mitigation potential of the 2.3 × 106 km2 of Canada's managed forests from 2015 to 2050 using the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3), a harvested wood products model that estimates emissions based on product half-life decay times, and an account of emission substitution benefits from the use of wood products and bioenergy. We examine several mitigation scenarios with different assumptions about forest management activity levels relative to a base-case scenario, including improved growth from silvicultural activities, increased harvest and residue management for bioenergy, and reduced harvest for conservation. We combine forest management options with two mitigation scenarios for harvested wood product use involving an increase in either long-lived products or bioenergy uses. Results demonstrate large differences among alternative scenarios, and we identify potential mitigation scenarios with increasing benefits to the atmosphere for many decades into the future, as well as scenarios with no net benefit over many decades. The greatest mitigation impact was achieved through a mix of strategies that varied across the country and had cumulative mitigation of 254 Tg CO2e in 2030, and 1180 Tg CO2e in 2050. We conclude that (i) national-scale forest sector mitigation options need to be assessed rigorously from a systems perspective to avoid the development of policies that deliver no net benefits to the atmosphere, (ii) a mix of strategies implemented across the country achieves the greatest mitigation impact, and (iii) because of the time delays in achieving carbon benefits for many forest-based mitigation activities, future contributions of the forest sector to climate mitigation can be maximized if implemented soon.

Climate change mitigation potential of local use of harvest residues for bioenergy in Canada

“…Compared to a strategy of using more of the stem harvest for longer-lived wood products, the national-level mitigation estimates were similar to results from this study (435 TgCO 2 e vs. 429 TgCO 2 e) but the allocation by ecozone was different: roughly half of the cumulative mitigation potential in this study was concentrated in one ecozone (Atlantic Maritimes), whereas the contribution from longer-lived wood products was Fig. 6 Comparison of mitigation strategies from Smyth et al (2014) to results from this study. Ecozones with higher mitigation potential from production of bioenergy from harvest residues (present results) are below the 1 : 1 line.…”

“…This study is the first comprehensive integrated analysis of the climate change mitigation potential for bioenergy from captured harvest residues for Canada's managed forest. It builds on the integrated analysis of the climate change mitigation potential for Canada's managed forest for seven forest management strategies and two harvested wood products strategies examined in Smyth et al (2014). Comparisons are made to the results from the earlier analyses to assess the mitigation potential for bioenergy from harvest residues relative to three strategies: increasing the longevity of HWPs, better utilization that alters forest management practices, and harvesting less.…”

Fibre use, net calorific value, and consumption of forest-derived bioenergy in British Columbia, Canada

“…Some or all of those emissions are taken up over time as the forest regrows. Improved modelling and tracking of fibre use, including combustion [4] and forest carbon dynamics [14], allows climate change mitigation scenarios and options to be modelled for the combined forestry and forest products sectors [15].…”

Carbon calculator tracks the climate benefits of managed private forests

“…As noted earlier, uncertainty remains on how to account for future rates of forest growth as well as climate benefits that accrue outside of the forest sector related to using wood products and bioenergy rather than fossil fuel-intensive products such as cement, steel, coal and natural gas (Smyth et al 2014). We cannot accurately predict how future forest growth rates will compare to the historic rates used in the calculator.…”

“…Emissions from wood used for bioenergy are not included in national emission totals since they reduce the need to burn fossil fuels (US EPA 2014). Sequestration benefits of using wood for bioenergy depend on fossil fuel displacement and how the bioenergy utilization is integrated with overall forest management (Malmsheimer et al 2011;Smyth et al 2014). At the state level, California's 2014 Climate Change Scoping Plan mentions the positive benefits of using more wood products in construction and more wood chips to generate energy, but the accounting framework and recommended policies focus only on increasing carbon inventories in the forest (California Air Resources Board 2014).…”