DISSERTATION RESEARCH: Forest climate requirements change through species life history

全球变暖预计将对许多物种产生强烈的负面影响。一种可能减少这些影响的方法是，如果物种可以随着气候变化改变它们的地理范围；如果物种可以随着气温上升迁移到更凉爽的地方，比如更高的纬度或海拔，它们或许能够通过改变地点来保持在相同的气候中。然而，该项目的初步研究表明，美国东部的树种并没有向北迁移。该项目将测试两种可供选择的假说来解释这一点，这两种假说都是基于幼树和成年树在耐受各种环境条件方面的能力是否不同。研究人员将扩展目前的物种分布模型，以包括更明显的青少年和成人对温度的反应的影响，并使用国家森林调查和气候测量的数据来比较青少年和成年人的数量。对抗气候变化对美国森林的影响是森林管理者和整个国家的一个重要问题。该项目的成果将有助于规划维持森林生产力和替代土地用途的战略。该项目还将加强杜克大学和美国农业部林务局之间的合作，并培养一名博士生和一名本科生。

Global warming is expected to have strongly negative effects on many species. One way these effects might be reduced is if species can change their geographical ranges as climate changes; if species can migrate to cooler places such as higher latitudes or elevations as temperature rises, they may be able to stay in the same climate by changing place. However, the preliminary research for this project shows that species of trees in the eastern U.S. have not moved northward. The project will test two alternative hypotheses to explain this, both based on whether young and adult trees differ in their ability to tolerate a wide range of environmental conditions. Researchers will expand a current species distribution model to include more explicit effects of juvenile and adult responses to temperature, and use data from a national forest inventory and climate measurements to compare the abundances of juveniles and adults.Anticipating the impacts of climate change on U.S. forests is an important issue for forest managers and for the nation as a whole. Results from this project will help plan strategies for maintaining forest productivity and for substitutions of alternative land uses. The project will also strengthen collaboration between Duke University and the USDA Forest Service, and train a Ph.D. student and an undergraduate student.