以競爭指數配合搜尋半徑預測單木胸徑及胸高斷面積生長之研究－以紅檜人工林為例

Predicting Individual Tree Diameter and Basal Area Growth by Competition Indices with Search Radii-An Illustration of Taiwan Red Cypress (Chamaecyparis Formosensis) Plantations

李隆恩(Long-En Li) ； 顏添明(Tian-Ming Yen)

《中華林學季刊》 45卷3期 (2012/09) Pp. 351-363

https://doi.org/10.30064/QJCF.201209.0006

摘要

本研究的目的在於探討競爭效應與紅檜（Chamaecyparis fomosensis）人工林單木胸徑及胸高斷面積生長之關係，研究區域位於台灣中部地區（120°57'E，24°15'N）之疏伐林分，並使用競爭指數及搜尋半徑推佑紅檜單木生長量。所得結果顯示，Lorimer2和Hegyi指數有較佳的預測效力，而固定半徑法較影響區域重疊法適用於紅檜人工林，且搜尋半徑以7－8m較為適合。此外，加入競爭指數於生長模式中將可有效提升模式預測能力及降低平均誤差平方和，而胸高斷面積生長模式配適結果優於胸徑生長模式，研究結果證實競爭指數可有效預測紅檜人工林之單木生長。

關鍵字

競爭指數 ； 生長模式 ； 紅檜

並列摘要

The purpose of this study was to discuss the relationships between competition effects and individual tree diameter and basal area growth for Taiwan red cypress (Chamaecyparis formosensis) plantations. The study plantations were located in central Taiwan (120°57'E, 24°15'N) and had thinning treatments. Competition indices with search radii were used to evaluate individual tree growth. We found that the Lorimer2 and Hegyi indices had well predicted capacities to individual tree growth. Moreover, the fixed radius method was better than the influence-zone overlap method where 7-8 m was suitable for determining radius range in the fixed radius. As the competition indices were added to predict tree growth, the growth model can improve predicted capacity and reduce mean square error (MSE). Comparisons of the predicted capacity by competition indices we found that the basal area growth model was better than DBH growth model. It implicated that competition indices can effectively predict individual tree growth of Taiwan red cypress.

並列關鍵字

Competition index ； Growth model ； Taiwan red cypress (Chamaecyparis formosensis)