白桦林“维他”机制研究(13)——边缘效应与增产机制和多样性的关系

WHITE BIRCH STAND SAFEGUARD MECHANISM (13) ——Relation between Edge Effect and lncrement Mechanism and Plant Diversity

分别在白桦幼林、中龄林和成熟林的林缘和林内设置样地２０块、样方１６０个，研究边缘效应与增产机制和多样性的关系。结果表明：①边缘效应可使白桦林树高增产１９％～４１％，胸径增产８％～１１％；其中，幼林高效应４．４８，径效应１．０７，中龄林高效应２．８１，径效应－１．１８，成林高效应１．１１，径效应－０．１９。②边缘效应表现显著的树种有红松、白桦、山杨和黑桦。③边缘效应可增加植物多样性１．３～１．６倍。④通过定义容他量和容他面积，说明了白桦林从幼龄到成龄是一个由自稳态经扩大领域态到自解体态的过程；其中处于扩大领域态的白桦中龄林的容乔量为０．２种／ｍ２、容灌量为０．２种／ｍ２、容草量为０．９种／ｍ２、容红量为０．２７株／ｍ２。

With 160 sample squares in the 20 experiment plots of young, midage and mature white birch stands, we studied the relation between edge (or fringe) effect and increment mechanism and plant diversity. The results show that: ①Tree height and d.b.h. increments produced by the stand edge effect (E) are 19%～41% and 8%～11% respectively: hE (height effect) =448,dE(diameter effect) =107 for young stand, the hE=291, dE=119 for mid-age one, hE=111, dE=-019 for mature one. ② The significant edge effect was found in Korean pine, white birch, black birch and aspen stands. ③ Edge effect increased the plant diversity by 13～16 fold. ④ The development process of a white birch stand from young to mature includes stable, expanding and disintegration stages according to the concepts of permissible load and area delined during the research; and the vallues of the load are 02 species/m2 for tree, 02 species/m2 for Korean pine. 