在以往的林分密度控制试验中,对降水环境容量问题或土壤水分承载量问题关注较少,未充分考虑到土壤的水分、养分等重要环境因子对植物数量与种类的限制作用.在浑善达克沙地南缘的三道河口林场范围内,首次通过探索应用土壤水分和养分承载力来确定樟子松人工林的林分合理密度,研究结果表明,若林分郁闭度大于0.8时,水耗严重,在干旱年份易导致林分大面积死亡,当樟子松人工幼林40 cm土层的土壤含水量小于3.8%时,立木出现旱死现象.建议将当地樟子松人工林的郁闭度控制在0.6~0.7为宜.%The restriction function of soil water and nutrients on the species and number of plants was not considered fully in previous experiments on forest stand density,i.e.the issue of environmental capacity of precipitation resource or the issue of bearing capacity of soil water.Based on the investigation for the bearing capacity of soil water and nutrition, the optimum stand density of Pinus sylvestris var.mongolica plantation was analyzed for the first time in the Sandaohekou forest farm which was in the south edge of the Hunshandake sand land.The results showed that the water consumption was serious and mass forest was dead when the canopy density was over 0.8,and that the standing trees began to dry out when water content of 40 cm soil layer of young P.sylvestris var.mongolica plantations was less than 3.8%.There-fore,this paper suggested that the optimum density of local P.sylvestris var.mongolica plantations would be 0.6~0.7.
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