Modeling mortality of second-rotation loblolly pine plantations in the Piedmont/Upper Coastal Plain and Lower Coastal Plain of the southern United States
Modeling mortality of second-rotation loblolly pine plantations in the Piedmont/Upper Coastal Plain and Lower Coastal Plain of the southern United States
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DOI：
10.1016/j.foreco.2007.06.030
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发表时间：
2007-11
影响因子：
3.7
通讯作者：
Dehai Zhao;B. Borders;Mingliang Wang;Michael B Kane
中科院分区：
文献类型：
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作者：
Dehai Zhao;B. Borders;Mingliang Wang;Michael B Kane
从6个火炬松研究永久地块的重新测量数据被用来开发死亡率模型的第二轮火炬松种植在皮埃蒙特/上海岸平原（PUCP）和下海岸平原（LCP）的美国南部。该模型由两个互补的部分组成：一个广义的逻辑方程，预测所有树木的生存概率在一段时间内开发使用所有数据与不发生死亡率;和一个差分方程预测树木数量减少，鉴于一些死亡率已经发生。在PUCP中，存活概率主要受林龄、密度和地位指数的影响，存活概率随着这三个变量的值的增加而减小。在LCP中，生存概率与林分断面积和地位指数有关，概率随林分断面积的增加而减小，但随地位指数的增加而增大。二代火炬松人工林的相对瞬时死亡率与林分密度、年龄和地位指数成正比，但在PUCP和LCP中年龄和地位指数的作用不同。因此，这两个地区的最佳差异死亡率方程的两种不同的形式得到。生存概率方程和差分死亡率方程均表明，在两个区域，立地生产力对死亡率的影响方向相反：在PUCP，死亡率随生产力的增加而增加，而在LCP，较高的死亡率与较低的生产力有关。PUCP中较低质量的位点可以支持比LCP中相同质量的位点更高的放养，而PUCP中较高质量的位点可以支持比LCP中相同质量的位点更低的放养。
Remeasurement data from permanent plots of six loblolly pine studies were used to develop mortality models for second-rotation loblolly pine plantations growing in the Piedmont/Upper Coastal Plain (PUCP) and Lower Coastal Plain (LCP) of the southern United States. The model consists of two complementary parts: a generalized logistic equation predicting the probability of survival for all trees over a period developed using all data with and without occurrence of mortality; and a difference equation predicting tree-number reduction, given that some mortality has occurred. In the PUCP, the survival probability is mainly affected by stand age, tree density, and site index; the probability decreases with increasing values of each of these three variables. In the LCP, the survival probability is related to the stand basal area and site index; the probability decreases with increasing stand basal area, but increases with increasing site index. The relative rates of instantaneous mortality for second-rotation loblolly pine plantations are proportional to stand density, age and site index, but with different functions of age and site index in the PUCP and LCP. Thus, two different forms of the best difference mortality equations were obtained for these two regions. Both survival probability equation and difference mortality equation indicate that site productivity affects mortality in an opposite way in the two regions: mortality increases with increasing productivity in the PUCP, but in the LCP higher mortality is related to lower productivity. The lower quality sites in the PUCP may support higher stocking than the same quality of sites in the LCP, while the higher quality sites in the PUCP may support lower stocking than the same quality of sites in the LCP.