浑善达克沙地境内沙地榆的自然更新

Natural Regeneration of Ulmus Pumila var. Sabulosa in Hunshandake Sandy Land

对不同生境下浑善达克沙地榆(Ul mus pumila L.var.sabulosa J.H.Guo Y.S.Li)林下幼苗的密度、生长情况及林缘、单株下幼苗扩散分布进行了野外调查研究,运用种群生态学方法及数理统计方法分析了其更新规律。结果表明,浑善达克沙地榆幼苗的密度为流动沙丘>半固定沙地>固定沙地;固定沙地、流动沙丘幼苗生长较差且流动沙丘幼苗死亡现象严重,半固定沙地幼苗生长较好更适于沙地榆的更新;幼苗主要集中分布于距林缘20m范围内,20m外幼苗密度显著降低;风向对浑善达克沙地榆的分布有较大的影响。

An investigation of Ulmus pumila var.sabulosa was carried out in the different habitats of Hunshandake sandy land,including both seedling density and seedling growth.Seeding density of dispersal under single trees and the edge of forest was studied.Its natural regeneration was analyzed using population ecology method and mathematical statistic method.Results showed that by seeding density,land units was in the order of shifting dune semi-fixed sandy land fixed sandy land.Seedlings grew badly in fixed sandy land and shifting dune and seedling death phenomenon was serious in shifting dune.Seedlings grew well in semi-fixed sandy land.Compared with fixed sandy land and shifting dune,semi-fixed sandy land was suitable to the habitat of natural regeneration.Seedlings were mainly distributed within the area 20 m from the edge of forest and outside 20 m,seedling density was reduced obviously.Wind direction had greater influence on seedling density and by seeding density.