RAPID: Forest dynamics driven by canopy defoliation during insect outbreaks

本项目将研究森林树毛虫（Malacosoma disstria）的爆发对温带森林树苗建立、生产力和群落结构的影响。偶尔会有昆虫爆发，使整个森林冠层脱落，可能只持续一两年。因此，它们得到的研究有限。然而，考虑到树木的长寿命，落叶事件可能是决定森林长期动态和演替的重要因素。先前的研究主要集中在落叶对树木生长和生存的负面影响；增加林下光照和土壤养分对树苗形成的积极影响却很少得到重视。该项目利用了密歇根州下游地区森林树木毛虫的大规模爆发，该地区包括以前建立的长期研究地点。来自长期研究的树木动态数据提供了一个罕见的基线，可以与昆虫爆发的影响进行比较。至关重要的是，这项研究立即开始，以便在落叶事件高峰期收集数据。因此，该项目是作为快速反应研究（rapid）的赠款资助的。气候变暖导致温带森林的生长季节变长，冬季变暖，这应该导致更频繁地爆发昆虫掠叶动物。这个项目将提供关于这种变化对森林动态的影响的重要资料。这项研究将在马尼斯蒂国家森林进行，对该森林和温带类似森林的管理具有重要意义。该项目将为一名博士后、研究生和本科生提供研究培训。当地K-12学校的师生也将参与实地调研。

This project will study the impact of an outbreak of the forest tree caterpillar (Malacosoma disstria) on tree seedling establishment, productivity and community structure of temperate forests. Outbreaks of insects that defoliate whole forest canopies occur sporadically and may last only a year or two. For this reason, they have received limited study. However, considering the long lifespan of trees, defoliation events may be an important factor determining the long term dynamics and succession within forests. Prior research has focused on the negative impacts of defoliation on tree growth and survival; far less attention has been given to the positive impacts on tree seedling establishment associated with increased understory light and soil nutrients. This project takes advantage of an ongoing, massive outbreak of forest tree caterpillars in a section of lower Michigan that encompasses previously established long term research sites. The data on tree dynamics from the long term study provide a rare baseline against which the impact of the insect outbreak can be compared. It is critical that this research start immediately in order to collect data during the peak of the defoliation event. Consequently, this project is being funded as a grant for rapid response research (RAPID).Climate warming has resulted in longer growing seasons and milder winters in temperate forests, which should lead to more frequent outbreaks of insect defoliators. This project will provide important information on the consequences of such change to forest dynamics. This research will be conducted in the Manistee National Forest and has important implications to the management of this forest and similar forests in the temperate zone. The project will provide research training for a postdoctoral scholar and for graduate and undergraduate students. Local K-12 school teachers and students will also be engaged in the field research.