Silvicultural control of spruce budworm

每年，森林病虫害导致加拿大森林纤维生产力下降30%(Caroll和Volney 2002)。在最近一次暴发期间(1968-1987)，云杉潜伏虫在魁北克省造成5亿立方米的损失(死亡+生长减少)(Coulombe等人)。2004年)。魁北克北方商品林最近推广了部分采伐，以增加森林实践的社会接受度，产生高质量的原木，在可持续产量的背景下，随着时间的推移修改树木采伐时间表，并管理野生动物栖息地。我们假设，部分采伐也可以用来增加寄主树对云杉芽孢子虫的抵抗力，因此可以减少这种主要森林害虫对加拿大经济的经济影响，但林分部分采伐的影响随着时间的推移和采伐密度的不同而不同，立地质量和寄主树种。目前研究方案中采用的科学方法包括根据测试的各种变量(部分采伐密度、立地质量、寄主物种)确定昆虫反应(幼虫生长、发育、食物利用和行为、成虫行为)、寄主树木反应(叶化学、树叶产量、被昆虫移除的叶子、生长、活力)和非生物条件变化(土壤和空气温度和湿度)。我们的科学方法不仅允许记录部分砍伐对寄主树木抗性的影响，还包括几个重要变量，而且还将使我们能够记录昆虫和寄主树层面上涉及的潜在生物和生理过程。这将有助于更好地理解如何通过营林做法来操纵针叶林，以减少云杉芽孢虫对加拿大经济的经济影响。此外，这项研究将提供更好的了解树木-昆虫相互作用的系统，从而可能对植物在云杉潜蝇种群动态中的作用产生重大影响。

Each year, forest insects and diseases damages cause 30% reduction in Canadian forest fiber productivity (Caroll and Volney 2002).  During its last outbreak (1968-1987), spruce budworm caused 500 million m3 losses (mortality + growth reduction) in the province of Quebec (Coulombe et al. 2004). Partial cutting in coniferous stands has been recently promoted in Quebec commercial boreal forest to increase the social acceptability of forest practices, to generate high quality logs, to modified schedules of tree harvesting over time in the context of sustainable yield, and to manage wildlife habitat.  We hypothesize that partial cutting could also be used to increase host tree resistance to spruce budworm and hence could reduce the economical impact of that major forest pest on the Canadian economy, but that the impact of stand partial cutting varies over time and according to the level of harvesting densities, site quality and host tree species.  The scientific approach adopted in the current research proposal involves the determination of insect responses (larval growth, development, food utilization and behavior, adult behavior), host tree responses (foliage chemistry, foliage production, foliage removed by the insect, growth, vigor) and abiotic conditions modifications (soil and air temperature and humidity) according to the various variables tested (partial cutting density, site quality, host species).  Our scientific approach will not only permit to document the impact of partial cutting on host tree resistance across a range of several important variables, but also will allow us to document the underlying biological and physiological processes involved at the insect and host tree level. This will contribute to a better understanding of how coniferous stand can be manipulated through silvicultural practices to reduce the economical impact of spruce budworm on the Canadian economy. Also, this study will provide a better understanding of the tree-insect system of interactions and consequently could have major impact on the role of the plant in the population dynamics of spruce budworm.