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

由于对气候的潜在负面影响，将整棵树用于生物能源生产引发了争议；这促使一些政策制定者考虑禁止将其作为生物能源原料。整棵树的一个特例是边缘纤维质量的树，如有缺陷的、腐烂的或垂死的树，在这里统称为退化树。*该计划的长期重点是提高有关加拿大森林的森林生物质原料动态的基础知识，以优化利用森林生物能源，为大气提供最大的好处。在接下来的五年里，该计划将专注于退化的树木，这些树木由于纤维质量低而不被传统的木制品行业所需要。它的目的是测试退化的树木可以在多大程度上成为可持续动员森林资源以缓解气候变化的一部分。该计划一方面将研究生态系统中生物质碳的动态，另一方面将生物质碳回收到技术系统中的能源产品中，决定森林立地过程中退化树木含量的命运和生物质到生物质能的转化。然后，这些成果将纳入森林生物能源系统和更大的森林管理系统。短期目标是：1--评估在林地(生态系统)上发现的退化树木随时间的碳动态；2--评估生物能源转换潜力和从退化树木(技术系统)中将木材碳回收为能源产品的潜力；3--作为较大森林管理系统的一部分，评估作为生物能源系统原料的退化树木的碳平衡和减缓气候变化的潜力。*拟议的项目将专注于加拿大东部森林中典型的两种退化树木：由于纤维质量较低，目前它们对传统木材产品的使用很少或根本没有用处：i)魁北克北部地区由云杉潜蝇落叶的香脂冷杉；ii)在魁北克南部和西部受到山毛榉树皮病侵袭的美洲山毛榉。*我的研究计划解决了21世纪两个相互关联的主要挑战，能源转换和减缓气候变化。该计划的三个项目旨在显著促进生态和技术系统中木质材料碳循环的基础知识，以及这些系统和大气之间的关系。它还将向需要尽可能最佳数据的加拿大利益攸关方提供信息，以评估真正有助于减少温室气体排放和缓解气候变化的能源生产情景。该计划将允许以跨学科的思维方式培训几名HQP，为培养能够全面解决气候变化和能源转型等社会问题的新一代专业人员和科学家做出贡献。

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.