Growth Variation in a Naturally Established Population of Pinus Sylvestris
Growth Variation in a Naturally Established Population of Pinus Sylvestris
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DOI：
10.2307/1941724
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发表时间：
1994-04
期刊：
影响因子：
4.8
通讯作者：
P. Stoll;J. Weiner;B. Schmid
中科院分区：
文献类型：
--
作者：
P. Stoll;J. Weiner;B. Schmid
我们研究了在苏黎世附近的樟子松种群中个体树木的生长变化与树龄、大小和当地竞争的关系。第二次世界大战后，泥炭沼泽的排水模式发生了变化，从而自然形成了这种流行。1987年，作为恢复计划的一部分，树木被收割，这是一个研究林分发展的不寻常的机会。所有的树桩进行了映射，并建立以来的增长进行了测量，木材的横截面积在5年的时间间隔，从每棵树的基础上使用磁盘。横截面积的分布是对数正态分布在大部分的生长期。在一个时间间隔的开始大小是在该间隔期间的个体生长的主要决定因素，但年龄和本地竞争也有显着的影响。年轻，较小的树木更好地拟合指数增长模型，而老年人，较大的树木更好地拟合Gompertz（S形）模型。结果表明：（1）树木的空间分布与随机分布差异不显著。(2)在林分发育过程中，即使没有自疏，大小变异性也有所下降。这是因为（3）林分自然建群密度低，竞争虽明显，但经过45年的发展，竞争仍较弱，且呈对称性。因此，在竞争中没有“初始优势”，仍然呈指数增长的小树能够赶上相对增长率正在下降的老树。
We studied the variation in growth of individual trees in a population of Pinus sylvestris near Zurich in relation to tree age, size, and local competition. This pop- ulation established naturally when the drainage pattern in a peat bog was altered after the Second World War. An unusual opportunity to study stand development was afforded when the trees were harvested in 1987 as part of a restoration program. All tree stumps were mapped, and growth since establishment was measured as cross-sectional area of wood in 5-yr intervals, using disks from the base of each tree. The distribution of cross-sectional area was lognormal over most of the period of growth. Size at the beginning of a time interval was the primary determinant of individual growth during that interval, but age and local competition also had significant effects. Younger, smaller trees were better fitted by an exponential growth model, whereas older, larger trees were better fitted by a Gompertz (sigmoidal) model. Some of the results were very different from previous studies: (1) The spatial distribution of trees was not significantly different from random. (2) Size variability decreased during the course of stand development, even though there was no self-thinning. This was because (3) the density of natural establishment was low, and competition, although clearly detectable, was still relatively weak and sym- metric after 45 yr of stand development. Thus, there was no "initial advantage" in com- petition, and the younger trees, which were still growing exponentially, were able to catch up with the older trees, whose relative growth rates were declining.