Partial Harvesting Regimes as Management Tools for Forested Landscape Mosaics

了解单株树木之间相互作用的影响对森林生态系统可持续管理的发展至关重要，特别是在混合树种、年龄不均匀的林分中。制定可持续林业处方战略的独特挑战之一是管理采伐和剩余树木分布的斑块性，以及这种斑块性如何影响未来林分动态。任何给定的部分采伐的长期后果将是剩余林分的即时结构和随后剩余树木生长的函数。预测部分采伐的这些长期间接影响需要使用基于数据的森林动态模拟模型。该研究将采伐效应纳入森林动态的空间显式模型（SORTIE）。我建议使用在新英格兰南部森林获得的数据来探索不同采伐制度对决定剩余树木生长和存活的竞争相互作用的影响，从而对不同采伐制度产生的景观模式的影响。这是发展维持林分组成和结构多样化，同时提供经济上可行的产量的造林系统的关键组成部分。森林管理者需要帮助来确定特定林分中部分采伐的最佳空间格局。该格局将是现有林分结构和组成以及未来期望的林分结构和组成的函数。本研究将探讨树种多样性和丰度对森林动态和林分生物量生产的影响。这是生态学中一个重要的理论问题，但很少利用树木群落进行探索。SORTIE提供了一个机制框架来量化物种特异性过程（即补充、生长或死亡）对物种丰度和林分生物量的贡献。了解物种间相互作用的群落结果对联系植物群落的过程和模式至关重要。量化这些相互作用的规模和重要性也是生态学中一个重要且持续的争论的核心，即竞争（即生态位分化）在构建自然植物群落中的重要性。

Understanding the effects of interactions between individual trees is critical to the development of sustainable management of forest ecosystems, particularly in mixed-species, uneven-aged stands. One of the unique challenges to developing prescription strategies for sustainable forestry is the management of patchiness in the distribution of both harvested and residual trees and how that patchiness affects future stand dynamics. The long-term consequences of any given partial harvest will be a function of both the immediate configuration of the residual stand and the subsequent growth of residual trees. Predicting these long-term, indirect effects of partial harvesting requires the use of data-based simulation model of forest dynamics. The proposed research incorporates harvest effects into a spatially-explicit model of forest dynamics (SORTIE). I propose to use data obtained in southern New England forests to explore the implications of different harvesting regimes on the competitive interactions that determine growth and survival of the residual trees, and therefore on the landscape patterns generated by different harvesting regimes. This is a critical component of the development of silvicultural systems that maintain diverse stand composition and structure, while providing economically viable yields. Forest managers need help to determine the optimal spatial pattern of partial cutting in a given stand. The pattern will be a function of existing stand structure and composition, and desired stand structureand composition in the future. The proposed research will explore the implications of tree species diversity and abundance on forest dynamics and stand biomass production. This is an important theoretical question in ecology which has rarely been explored using tree communities. SORTIE provides a mechanistic framework to quantify the contribution of species-specific processes (i.e., recruitment, growth or mortality) on both species abundance and stand biomass. Understanding the community consequences of interactions between species is essential to linking process and pattern in plant communities. Quantifying the magnitude and significance of these interactions is also at the heart of an important and ongoing debate in ecology, amely the importance of competition (i.e., niche differentiation) in structuringnatural plant communities.