Conversion from simple coppice to species rich high forest

我们建议在灌木林中设置人工林隙，以协调植物物种多样性的恢复和退耕还林。为了达到这些目的，我们首先提出了一种在人工林隙采伐前估算林下光照水平的新方法。数据是从“擦除法”中获得的，在这种方法中，光线水平是通过使用半球照片的计算机图像来估计的，在这些照片上，假定被切割的牙冠是数字化的。该公式的优点是计算所需的指数在树冠投影图上都能很容易地测量出来。平均植物种数和物种多样性随林隙大小的增大而增加。在这些林隙中，冠层树种当年苗密度因光照强度和凋落物盖度的不同而不同。林隙形成后，邻近林隙的树木直径生长发生了变化。树种特征反映在生长率上，从单纯的灌丛结构向人工林隙的复杂林分结构转变，有利于协调植物物种多样性的恢复和向高大林的转变。

We proposed to create artificial gaps in coppice stand for harmonizing restoration of plant species diversity and conversion to high forest. For these aims, we firstly presented a new method for estimating understory light level in and around artificial gap prior to cutting. Data were obtained from the 'erasing method' in which light levels are estimated by using computerized images of hemispherical photographs on which crowns assumed to be cut are digitally. The equation presented in this study has an advantage that the indices needed for calculation are able to measure easily in stands of even on crown projection diagrams.We created seven artificial gaps whose sizes are from 20 to 380 m^2 in derelict coppice. Mean number of plant species and their diversity were increased with gap size. In these gaps, densities of current year seedlings of canopy tree species were differently according to light intensity and litter cover. Diameter growth of trees being adjacent those gaps changed after creating the gaps. Species characteristics were reflected on the growth ratios.We concluded that the conversion from simple coppice to complex stand structure with artificial gap is available for harmonizing restoration of plant species diversity and conversion to high forest.