Predicting the vertical distribution of the stem cross-sectional area increment for an even-aged stand of hinoki cypress [Chamaecyparis obtusa]
2009
Waguchi, Y., Nara-ken. Forest Research Inst., Takatori (Japan)
As a useful tool for planning stand density management, a model to predict the vertical distribution of the stem cross-sectional area increment for even-aged stands of Hinoki cypress was developed. The model consists of two sub-models: one for predicting the distribution from total height and three sunny crown dimensions, and one for estimating these sunny crown dimensions using stand density and total height increment. The model requires three independent variables (stand density, total height and its increment) and seven parameters. To demonstrate the validity, the model was applied to five long-term permanent sample stands of Hinoki cypress. The model gave good predictions in most stands and growth stages. The model improves upon some shortcomings of existing models, and produces more realistic distributions at a practical level of precision. The model has wide applicability because it can predict distributions using common parameter values among stands or growth stages. Furthermore, the model has two constructional advantages. First, it is rationally designed through a growth process. Second, the model provides a simple and robust framework. Therefore, it is possible to modify the model for a particular aim, and to use it as a basis for other growth models. In conclusion, the model is a useful tool for planning stand density management for even-aged stands of Hinoki cypress.
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