共和盆地不同类型防护林的改善小气候效应

Improvement Effect on Microclimate in Different Types of Shelterbelt in the Gonghe Basin of Tibet Plateau

防护林是荒漠生态系统中绿洲的生态屏障。本文在青藏高原共和盆地的沙丘和丘间地生境中,分别选择不同类型的防护林,在春季和夏季测量它们的风速、气温、相对湿度、土壤温度和土壤体积含水量,据此选择改善小气候效应较好的防护林类型。结果表明:与流动沙丘相比,沙丘上栽植柠条和沙蒿均能够明显降低风速和气温,增加相对湿度,降低土壤温度,并且增加土壤体积含水量;柠条改善小气候的效应优于沙蒿。与赖草草地相比,丘间地各种类型的防护林均能够降低风速和气温,增加相对湿度,降低土壤温度,但是大部分防护林会降低土壤体积含水量,仅小叶杨林带能够在7月增加土壤体积含水量;小叶杨+乌柳混交林和乌柳+沙柳混交林改善小气候的效应优于柽柳和乌柳。

Shelterbelt is the eco-protection system for oasis in desert ecosystem.In this study,different types of shelterbelt in sand dune and interdune in Gonghe Basin of Tibet Plateau were observed to select those types which had better effects on microclimate improvement by measuring wind speed,air temperature,relative humidity,soil temperature and soil volumetric water content.The results showed that wind speed,air temperature and soil temperature was decreased,whereas relative humidity and soil water content was increased by Caragana intermedia and Artemisia ordosica in sand dune,compared with moving sand dune.Moreover,the microclimate improvement was better in C.intermedia than in A.ordosica in sand dune.Compared with natural Leymus secalinus grassland,wind speed,air temperature and soil temperature was decreased,whereas relative humidity was increased by all types of shelterbelt in interdune.However,soil water content was decreased by most types of shelterbelt,except for the increase of soil water content by Populus simonii shelterbelt in July.Moreover,the microclimate improvement was better in the mixed forest of P.simonii with Salix cheilophila or the mixed forest of S.cheilophila with S.psammophila than in the pure forest of Tamarix chinensisor S.cheilophila in interdune.