LTREB: Effects of Insect Defoliation on Nitrogen Loss from Forest Ecosystems

9527781洛维特这个项目解决了昆虫爆发和氮沉降在控制森林生态系统的氮循环和损失中的作用。关键的长期数据集舞毒蛾的丰度，森林落叶，并在高地橡树林东南部纽约州的养分循环将保持。这些森林受到周期性舞毒蛾爆发以及氮氧化物污染造成的氮大气沉降的影响。此外，提出了一个实验，这将澄清氮的可用性和落叶在调节氮损失的作用，并将加速氮积累的影响，将发生在一个更长的时间段从大气沉积。正在测试的假设指出，由于其氮有限的植被和土壤中的高固定潜力，橡树林最初将显示只有少量的氮损失后，落叶。然而，随着氮在森林中从大气沉积或施肥中积累，落叶事件后损失的氮量将增加。本研究的结果将阐明生态系统氮积累在控制落叶后氮损失中的作用，并将有助于评估昆虫落叶和氮沉降升高这两种同时影响东北森林的压力的相互作用。

9527781 Lovett This project addresses the role of insect outbreaks and nitrogen deposition in controlling the cycling and loss of nitrogen from forest ecosystems. Crucial long-term data sets on gypsy moth abundance, forest defoliation, and nutrient cycling in upland oak forests of southeastern New York State will be maintained. These forests are subject to periodic gypsy moth outbreaks as well as elevated atmospheric deposition of nitrogen from nitrogen oxide pollution. In addition, an experiment is proposed which will clarify the role of nitrogen availability and defoliation in regulating nitrogen loss, and will hasten the effects of nitrogen accumulation that would occur over a much longer time period from atmospheric deposition. The hypothesis being tested states that because of their nitrogen limited vegetation and high immobilization potential in the soil, oak forests will initially show only small nitrogen losses after defoliation. However, as nitrogen accumulates in the forests from atmospheric deposition or fertilization, the amount of nitrogen lost after defoliation events will increase. The results of this study will elucidate the role of ecosystem nitrogen accumulation in controlling nitrogen losses after defoliation, and will help evaluate the interactive effects of insect defoliation and elevated nitrogen deposition, two simultaneous stresses affecting northeastern forests.