Collaborative Research: Forest Dynamics in Heterogeneous Landscapes

在过去三百年的大部分时间里，新英格兰的定居导致了原生森林植被的破坏和破碎。最近，这个地区的森林更新有所增加。这项研究的目的是收集来自不同地点的实地数据，这些数据将用于根据实地测量的实际起始条件参数化森林发展模型。森林动态是种子传播、幼苗建立和组成物种差异生长速率的函数。在本研究中，将在一系列森林生境中进行实地试验，以确定种子传播和草食在影响森林更新中的作用。这些实验的结果将用于调整和改进称为SORTIE的森林动力学模型。诸如SORTIE之类的模型提供了已知条件下的基线数据，可以与之比较森林再生的实际模式。与该模型相关的机制将极大地提高我们预测森林植被变化的能力。预测变化的能力将对全球气候变化及其对未来生物多样性的影响具有重要意义。以前模拟森林动态的方法完全依赖于平均响应变量和平均环境条件。SORTIE模型比早期的模型有了很大的改进，因为它是真正的空间显式的。初始条件将由在田间测量的单个树木和树苗的位置得出。此外，还将测量不同林分的实际环境条件并将其纳入模型。正在测量食草动物在森林再生中的作用，并将其添加到模型中。最后，这个模型是一个进步，因为它包含了环境异质性。

Throughout much of the past three hundred years the settlement of New England has resulted in the destruction and fragmentation of native forest vegetation. Recently, there has been an increase in forest regeneration in this region. This study is designed to gather field data from a variety of sites that will be used to parameterize a model of forest development based on actual starting conditions measured in the field. Forest dynamics is a function of seed dispersal, seedling establishment, and differential growth rates of component species. In this study field experiments will be conducted in a range of forest habitats to determine the role of seed dispersal and herbivory in effecting forest regeneration. The results from these experiments will be used to adjust and improve the forest dynamics model called SORTIE. Models such as SORTIE provide baseline data under known conditions against which it will be possible to compare actual patterns of forest regeneration. The mechanisms associated with the model will dramatically increase our ability to predict changes in forest vegetation. The ability to predict changes will have important implications for global climate change and its effects on future biodiversity. %%% Previous approaches to modelling forest dynamics have relied exclusively on average response variables and average environmental conditions. The SORTIE model represents a vast improvement over earlier models because it is truly spatially explicit. Initial conditions will be derived from positions of individual trees and saplings measured in the field. In addition, the actual environmental conditions in different stands will be measured and incorporated into the model. The role of herbivores in forest regeneration is being measured and added to the model. Finally, this model represents an advance because it incorporates environmental heterogeneity.