人工云杉林试验林窗环境特征及对幼苗存活的影响

本实验在四川省理县米亚罗人工云杉林中制造实验林窗,对林窗和林下的土壤温度、空气温度、空气相对湿度、光照强度、土壤pH值和土壤含水量进行动态监测。结果表明：相比于林下,实验林窗内土壤和空气温度分别增加0.46℃和0.35℃,实验林窗内的光照强度增加了69.7%。实验林窗内空气相对湿度比林下的略高,土壤pH值和土壤含水量在实验林窗和林下没有显著变化,但存在一定季节动态。对两种生境下云杉更新幼苗存活调查结果显示,林下生境中更新幼苗全部死亡,而实验林窗中幼苗存活率高达23.75%。总之,云杉人工林制造实验林窗尽管对诸多环境因子影响并不明显,但是光照强度的增加显著提高了更新幼苗的存活率。

Environmental Characteristics of the Experimental Gap in a Spruce Plantation and their Effect on Survival of Seedlings

Artificial forest gaps were formed in a spruce plantation in Miyaluo,Li county,Western Sichuan.Environmental factors such as soil temperature,air temperature,relative air moisture,relative light intensiy,soil pH and soil moisture were continuously monitored in the gap and under the forest canopy.The results were shown as follows：soil air temperature in the gap increased by 0.46 ℃ and 0.35 ℃,respectively,compared with that under the forest canopy.Relative air mositure was slightly higher in the gap than under the forest canopy.However,in contrast with the forest canopy,artificial forest gap on average enhanced relative light intensity by 69.7%.No significant differences in pH between gap and forest canopy were detected but there was a seasonal change.Soil mositure in the gap was slightly higher than that under the forest canopy,but the difference was not significant.All spruce seedlings growing under the forest canopy were found to be dead,but the survival rate of the seedlings growing in the experimental gap was 23.75%.All in all,although experimental gap did not influence most of expeimental factors,significantly increased light intensity in the experimental gap partly enhanced the survival of the seedlings.Fig 8,Ref 19