Ecological characteristics of Chamaecyparis pisifera and its stand maintenance mechanism

柞蚕克隆斑块的发生格局和大小结构ENDL。，以及斑块所处的基质，分别在原生林中有封闭林分（closed stand）和有林隙（gap stand）的林分（gap stand）中进行了调查。两种林分中均有小树斑块（最高叶梢高度小于等于1.3m）和幼枝斑块（最高叶梢高度小于1.3m），且林隙内斑块数量多于封闭林分。这些斑块的大小分布呈反j型，小斑块数量较多，在幼斑块中更为典型。林隙林中幼树斑块的平均大小显著大于林隙林中幼树斑块的平均大小，而林隙林中较大幼树斑块的出现频率较高。这些斑块出现在各种基质上，在没有凋落物的地面上（包括岩石）更常见。在封闭林分中，落叶阔叶树冠下和林隙中斑块分布较多。它们可以在光照不足的条件下水平生长，也可以在相对较强的光照条件下达到高度生长。林隙的形成提高了下层的光照水平，对假凤仙花克隆的再生起着重要的作用

The occurrence pattern and size structure of clonal patches of Chamaecyparis pisifera (S.et Z.) ENDL., together with the substratum on which the patches were located, were investigated in a stand with a closed canopy (closed stand) and that with a canopy gap (gap stand) in an old-growth C.pisifera forest.Both sapling patches (patches with the height of the tallest foliage shoots <greater than or equal> 1.3m) and juvenile patches (those with that of <1.3m) occurred in both stands, and more abundant patches occurred in the gaps than in the closed stands.Size distributions of these patches were inverse J-shaped with more abundant smaller patches, and this was more typical for juvenile patches. Mean size of juvenile patches was significantly larger in the closed than in the gap stands, whereas larger sapling patches occurred more frequently in the gap stands.These patches occurred on various kinds of substrata and were more frequently on ground without litter, including rocks, in both stands. Patches occurred more abundantly under crowns of deciduous broadleaved trees in the closed stand, and in canopy gaps in the gap stands.They may expand horizontally by layning under insufficient sunlight conditions and may attain height growth under relatively strong sunlight conditions.Canopy gap formation that raises the sunlight level in the lower story plays an important role for the regeneration of C.pisifera from the clonal