Long observation period improves growth prediction in old Sugi (Cryptomeria japonica) forest plantations
Long observation period improves growth prediction in old Sugi (Cryptomeria japonica) forest plantations
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DOI：
10.1080/13416979.2020.1753280
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发表时间：
2020-04
影响因子：
1.5
通讯作者：
T. Hiroshima;Keisuke Toyama;Satoshi N. Suzuki;T. Owari;T. Nakajima;S. Ishibashi
中科院分区：
文献类型：
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作者：
T. Hiroshima;Keisuke Toyama;Satoshi N. Suzuki;T. Owari;T. Nakajima;S. Ishibashi
对杉人工林的老龄生长进行预测具有重要意义。当对杉人工林的生长进行预测时，缺乏来自老树的生长数据，这些预测的准确性可能会变得更差。例如，已知杉的生长在较老的年龄并不像根据从年轻到中年树的生长数据的过去生长预测所预期的那样变慢。研究了杉木人工林胸径外推值随模型校正训练数据观测期变化的规律。研究地点是东京大学千叶林和秩父林的杉人工林的长期生长观测点。本研究采用理查兹生长函数对单木胸径和林分平均胸径进行拟合。结果表明，在老年人的增长预测的准确性得到提高，包括足够数量的老树的增长数据。从另一个角度来看，如果生长数据没有包括足够的老树，那么对老树生长的预测往往会低估实际生长。
ABSTRACT It is important to predict the growth of Sugi forest plantations in old age. When predictions about the growth of Sugi forest plantations are made and there is a lack of growth data from older trees, it is possible that the accuracy of these predictions becomes worse. For example, it is known that the growth of Sugi does not get slower at older ages as expected from past growth predictions based on growth data from young to middle-aged trees. This study investigated the changes in extrapolated values of diameter at breast height (DBH) in old Sugi forest plantations with changes in the observation period of training data for model calibration. The study sites were long-term growth observation sites of Sugi forest plantations in the University of Tokyo Chiba Forest and Chichibu Forest. In this study, both DBH of individual trees and mean DBH of stands were analyzed by fitting Richards growth functions. The results showed that the accuracy of growth predictions in old ages was improved by including growth data from a sufficient number of older trees. From another point of view, growth prediction in old ages tended to underestimate actual growth if growth data did not include enough older trees.