U.S.-China Cooperative Research: Pine Sawfly Outbreak Distribution Patterns in Western U.S. and China: Role of Plant Quality

本研究计划旨在探讨中国和美国森林害虫爆发的根本生态原因。在本建议中，概述了将测试林分条件（年龄、密度、基因型）在松林易受经济上重要的森林掠叶昆虫——松锯蝇（膜翅目：姬蝇科）爆发的影响的实验。尽管大量文献表明林分条件是森林昆虫爆发的主要因素，但人们对这一普遍现象的基本机制知之甚少。在美国西部的黄松林和中国中部的云南松林中，出现了几乎相同的松锯蝇爆发模式。松锯蝇的爆发仅限于限制年龄的低密度林分。提出了一种强有力的实验方法来严格测试林分条件在中国和美国易患锯蝇病的树木中的重要性。将进行林分操纵，以实验方式创建林分密度，以复制已知支持松锯蝇爆发的林分密度。将检验两种假设机制对观察到的爆发模式的重要性。基本实验设计是在中国四川省和美国亚利桑那州进行平行研究。具体的研究活动包括Wagner博士每年1个月的访问和北亚利桑那大学的一名博士生和研究技术人员每年4-6个月的实地研究。本研究将由四川省林业科学研究院实验中心的一名科学家和研究人员协助。同样，四川省林科院的一名科学家将在两年的时间里，每年在美国亚利桑那州进行4-6个月的研究。中国科学家短期访问美国的研究设施和研究区域也将得到支持。Wagner博士和Hend Xiao先生都有丰富的松锯蝇工作经验。该项目将提高我们对森林昆虫暴发原因的基本认识，改善中美科学家的培训，加强中美之间的科学和文化交流。

This research proposal addresses the fundamental ecological cause of outbreaks of damaging forest insects in China and the United States. In this proposal experiments are outlined that will test the role of forest stand conditions (age, density, genotype) in predisposing pine forests to outbreak by an economically important group of forest defoliators - pine sawflies (Hymenoptera: Diprionidae). Despite extensive literature implicating stands conditions as a major factor in forest insect outbreaks little is known about the fundamental mechanisms responsible for this universal phenomenon. Nearly identical pine sawfly outbreak patterns occur in Pinus ponderosa forests of the western United States and Pinus yunnanenis forests of central China. Pine sawfly outbreaks are restricted to low density stands of a restricted age class. A strongly experimental approach is proposed to rigorously test the importance of stand conditions in predisposing trees to sawfly outbreaks in both China and the US. Stand manipulations will be conducted to experimentally create stand densities that replicate the densities of stands known to support pine sawfly outbreaks. The importance of two hypothesized mechanisms for the observed outbreak patterns will be tested. The basic experimental design is to conduct parallel studies in Sichuan Province, China and Arizona, USA. Specific research activities to be conducted include a 1 month visit by Dr. Wagner and 4-6 months of field research each year by a doctoral student and research technicians from Northern Arizona University. This research will assisted by a scientists and research staff of the Experiment Center of Sichuan Provincial Academy of Forestry Science. Similarly a scientist from the Sichuan Forestry Academy will conduct research in Arizona for 4-6 months each year for two years. Short term visits by Chinese scientists to research facilities and study areas in the US will also be supported. Dr. Wagner and Mr. Hend Xiao both have extensive previous experience working with pine sawflies on pine species. This project will improve our basic understanding of the causes of forest insect outbreaks, improve the training of US and Chinese scientists, and enhance scientific and cultural exchange between China and the United States.