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Growth and Yield Modeling
Planning Tools for Sustainable Forest Management
Refinement of the Forest Vegetation Simulator, Northeastern Variant, Growth and Yield Model
Forest managers rely on growth and yield models to assess whether their short term plans will meet long term sustainability goals. This is important from the standpoint of both the business and environmental viability of forestry in the long term. The models that are currently in use in the Maine were initially built on data from the 1970s and 1980s and often use older statistical techniques. Tests have shown that these models may not produce the best predictions of how the forests of Maine will grow. CFRU cooperators have recognized this deficiency and have set the development of better growth and yield models as one of their top research priorities. This project works towards achieving this goal by developing a large database of growth and yield data from the state of Maine and eastern Canadian Provinces. The data in this database are being analyzed with the latest statistical techniques to rebuild growth and yield model components with the ultimate goal of producing a refined growth and yield model. Look here for more information.
Development of regional taper and volume equations for the primary commercial species in the Acadian Region
A major component of a growth and yield system is a methodology for calculating tree volume. Statistical relationships between tree diameter and merchantable volume have been used in the northeast for several decades. Several other regions in the United States have begun to calculate volumes based statistical models of tree taper. The approach using taper has shown to have several strengths including the ability to adapt to changes in the definition of merchantability. As part of the CFRU’s effort to improve growth and yield modeling in Maine, this project seeks to build taper equations for the primary commercial species of this region so as to improve volume estimation. For more information on this project, see the proposal here.
Modeling Natural Regeneration and Ingrowth in Managed Stands of the Acadian Region
A growth and yield model that is used to assess the long term sustainability of forest practices needs to not only be able to accurately predict how existing trees will grow, but also be able to accurately predict what type of, and how many, new trees will enter the forest given different growing conditions and disturbances. Despite the obvious importance of this modeling component, it is usually an area of weakness for growth and yield models, and the models currently in use in the northeast are no exception. This project attempts to contribute to the growth and yield modeling effort supported by the members of the CFRU by developing statistical models that explain what types of trees will enter a stand given various conditions as well as how many of these trees will appear. For more information on this project, see the proposal here.
Exploring the Effects of Thinning on Stand – and – Tree-Level Mortality in Maine’s Spruce-Fir Forests
A good growth and yield model should have the ability to accurately predict which trees will die as well as predicting which trees will grow. In many cases tree mortality can change given different site conditions, and especially given different harvest treatments. This study asses how thinning treatments in the CFRU’s Commercial Thinning Research Network (CTRN) effects mortality at both the tree and stand level and thus contribute to the overall growth and yield modeling effort. Another critical contribution of this study is adding site quality and soils data to the already extensive CTRN database. This will not only assist in this study, but other studies conducted with the CTRN database. For more information on this project, see the proposal here.
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