Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations
Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations
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DOI：
10.1007/s10310-005-0175-6
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发表时间：
2006-08
影响因子：
1.5
通讯作者：
T. Masaki;S. Mori;T. Kajimoto;G. Hitsuma;S. Sawata;M. Mori;K. Osumi;S. Sakurai;T. Seki
中科院分区：
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作者：
T. Masaki;S. Mori;T. Kajimoto;G. Hitsuma;S. Sawata;M. Mori;K. Osumi;S. Sakurai;T. Seki
通过对45 ~ 94年生日本柳杉人工同龄种植园单株胸径生长的分析，探讨间伐后株距变化对单株生长的影响。在任何年龄，一个显着的比例（0.37-0.46）的胸径生长在5-11年期间的变化解释了胸径在开始的时期，可能是由于较大的树木更大的叶质量。接下来，通过计算给定半径内每棵树周围相邻树木的断面积（BA）或半径内胸径大于焦点树的树木的BA，将单侧或双侧竞争添加到模型中。经初步分析，确定8 m半径为林木竞争的临界范围。虽然这两种类型的竞争解释了显着比例（0.09-0.43）的增长变化，单侧竞争是不显着的年龄大于54岁。基于45年树龄的模型，计算每棵树的生长速率与预测速率的初始偏差，并将其作为第三变量添加到模型中。这将决定系数提高到0.50-0.74。这些研究结果对种植园管理，特别是通过间伐控制立木生长，生产优质木材具有现实意义。
The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation ofCryptomeria japonicafrom stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37–0.46) of the variation in dbh growth during a 5–11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09–0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50–0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.