Can degraded trees serve as sustainable feedstock for forest bioenergy production?

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The use of whole trees for bioenergy production stirs controversy due to potential negative impacts on climate; this has brought some policymakers to consider banning them as a bioenergy feedstock. A special case of whole trees is trees of marginal fibre quality, such as defective, decaying or dying trees, together referred here as degraded trees. The long-term focus of the program is to improve fundamental knowledge about dynamics of forest biomass feedstocks from Canadian forests for an optimized utilisation of forest bioenergy providing the greatest benefits to the atmosphere. Over the next five years, the program will focus on degraded trees that are unwanted by conventional wood product industries due to their low fibre quality. It aims to test to what extent degraded trees can be part of a sustainable mobilisation of forest resources for climate change mitigation. The program will study biomass carbon dynamics in ecological systems on one hand, and biomass carbon recovery into energy products in technological systems on the other hand, determining the fate of the content of degraded trees during forest site processes and biomass-to-bioenergy conversion. These results will then be integrated within forest bioenergy systems and larger forest management systems. The short-term objectives are to: 1- assess the carbon dynamics of degraded trees through time as found on forest sites (ecological systems); 2- assess the bioenergy conversion potential and carbon recovery into energy products of wood from degraded trees (technological systems); 3- assess the carbon balance and climate change mitigation potential of degraded trees as feedstocks for bioenergy systems, as part of larger forest management systems. The proposed project will focus on two species of degraded trees typical of Canadian eastern forests:, and which currently have little or no use for conventional wood products due to low fibre quality : i) balsam fir defoliated by the spruce budworm in boreal regions of Quebec; ii) American beech attacked by the beech bark disease in south and western Quebec. My research program addresses two major and interlinked challenges of the 21st century, energy transition and climate change mitigation. The three projects of this program are designed to significantly contribute to fundamental knowledge on carbon cycling of woody material in ecological and in technological systems, and relationships between these systems and the atmosphere. It will also provide info to Canadian stakeholders who need the best data possible to appraise energy production scenarios that truly contribute to GHG emissions reduction and climate change mitigation. This program will allow the training of several HQPs in an interdisciplinary mindset, contributing to a new generation of professionals and scientists that can holistically address societal issues such as climate change and energy transition.