子午岭马兰林区辽东栎幼苗定居限制的初步研究

A pilot study of establishment limitation of Quercus wutaishanica seedlings in Malan Forest Region on Mt.Ziwuling

关键词:  黄土高原  播种实验  种子限制  微生境限制

Key words:  Loess Plateau  seed sowing experiment  seed limitation  microsite limitation

摘要:

在子午岭马兰林区选择油松林、辽东栎林、灌丛、草地等四种群落,通过播种实验及3 a的跟踪调查,研究四种不同生境下辽东栎幼苗在定居过程中的生长规律。结果显示:在四种生境中,人为增加辽东栎种子密度,均能明显提高出苗量,幼苗生长三年后大量死亡,死亡高峰出现在第三年。郁闭生境下(油松林和辽东栎林),辽东栎出苗率及存活率高于开阔生境(灌丛和草地)。辽东栎幼苗高生长及径向生长在三年间无显著差异。本地区辽东栎种群更新早期阶段存在种子和微生境的双重限制。枯落层厚度及光照强度是产生微生境限制的主要因素。通过人工播种并增加对枯落层的人为扰动,可能促进辽东栎种群向人工油松林的侵入。

Abstract:

In Manlan forest region on Mt.Ziwuling,four types of stands(Pinus tabulaeformis forest,Quercus wutaishanica forest,Shurb and Grassland)were selected for seed sowing experiments. The growth data of seedlings establishing in four habitats were measured continiously in 3 years. The results showed that,in every stands,seeds addition could lead to higher seedling emergence,but the great deal of seedlings were dead after three years and the peak value presented in the third year. Under closure conifer and oak forest canopies,the seedling emergence and survival rates of Q.wutaishanica were higher than them in open shrub and grassland stands. The seedling height and diameter had no significant difference among three years. The early regeneration of Q.wutaishanica in this local,was limited by seed and microsite together. The litter thickness and light intensity were the primary microsite limitation factors. The invasion of Q.wutaishanica towards conifer plantation may be improved by artificial seed sowing and litter disturbing.