Dissertation Research: Changes in Performance Ranking of Seedlings of Coexisting Tree Species Under Different Combi- nations of Light, Mineral Nutrients and Soil Moisture

这是由费城宾夕法尼亚大学的布兰达·卡斯珀博士和她的研究生罗杰·莱瑟姆先生提出的建议。他们假设，不同树种之间在幼苗时期对资源需求的差异可能不是湿润温带森林中物种共存的原因。本研究提出了一个合理的、组织严密的方案来评价不同树种幼苗对不同资源的响应差异。他们将对几种相互作用的树种对资源的反应进行全面分析。即使仅限于幼苗，它们也能很好地评估上述一般假设的可能性，从目前的情况来看，这是一个明确的经验进步，因为我们对它们所解决的问题有更多的想法，而不是数据。该研究背景较为成熟，汇集了种群生态学、生理生态学和生态系统生态学的一些思想和成果。这种综合方法是非常需要的，试点研究表明，拟议的工作将是一项很好的投资。研究结果对林业和森林管理具有重要意义。布伦达·卡斯珀博士在这一生态领域的地位越来越高，她最近的出版物受到了热烈的欢迎。宾夕法尼亚大学有充分的条件来完成这项工作。该项目建议提供资金。

This is a proposal by Dr. Brenda Casper and her graduate student Mr. Roger Latham of the University of Pennsylvania, Philadelphia. They postulate that differences among tree species in their resource requirements as seedlings may not be responsible for species coexistence in humid temperate forests. The research proposed presents a well reasoned and tightly oraganized plan to evaluate species differences in seedling response to different resources. They will provide a comprehensive analysis of the response to resources of several interacting tree species. Even though limited to seedlings, they will be in a good position to evaluate the possibility of the general hypothesis referred to above, a definite empirical advance from the present situation, as we have many more ideas than data on the questions they address. The context is well developed, and brings together some ideas and results from population ecology, physiological ecology and ecosystem ecology. This integrative approach is much needed and the pilot studies demonstrate that the proposed work will be a good investment. Results will be of importance to forestry and forest management. Dr. Brenda Casper is gaining in stature in this area of ecology as attested by an enthusiastic reception for her most recent publications. The University of Pennsylvania is well equipped to pursue this work to a successful completion. The program recommends funding.