石灰岩山地两种模式人工林小气候比较

Comparison of Microclimates in Two Mode Plantations in Limestone Mountain

为了探讨侧柏女贞混交林(CN)和侧柏纯林(CB)对林内小气候影响的差异,以便为分析不同模式林分生态效应提供依据,在春季、夏季、秋季和冬季对两种林分林内空气温湿度、土壤温度和土壤水分含量进行了观测,同时测定空地(CK)小气候指标作为对照。结果表明:夏季中午前后CN,CB和CK间气温差距最大,四季气温值均是CN最小、CK最大,春季和夏季CN与CB气温差异未达到显著水平,秋季和冬季气温值无差异;不同样地空气相对湿度基本为CN>CB>CK,且夏天空气相对湿度最高、春天最低,不同季节CN和CB空气相对湿度差异不显著;各样地地表温度均高于地下5cm温度,在温度较高的午后CN地表温度与地下5cm温度的差值比CB,CK小,夏季各样地地表与地下5cm土温差值最大、冬季最小;土壤含水量变化与空气相对湿度变化规律相似,表现为混交林土壤水分含量高于纯林。在炎热的夏季,混交林改善小气候的能力优于纯林,主要表现在降低并稳定气温和地温,增加空气湿度和土壤含水量。

To investigate differences between mixed plantation of Platycladusorientalisand Ligustrum lucidum（CN）and pure Platycladus orientalis forest（CB）effects on microclimate,and in order to provide basis for ecological effect analysis of different modes,air temperature,air relative humidity,soil temperature and soil water content were observed in four seasons,simultaneously measured parameters in open space（CK）were set as control microclimate indices.Results showed that in summer,temperature gaps of CN,CB and CK were the largest before and after noon,and temperature in four seasons was minimum in CN,maximum in CK.Mean monthly temperatures of CN and CB were different but not obvious in spring and summer,while similar in autumn and winter;air relative humidity was in the order of CN 〉CB〉 CK,and the highest value occurred in summer,the lowest in spring.Air relative humidity differences of CN and CB were not significant in four seasons.Surface temperatures were higher than temperatures in 5cm underground in three simple plots,CN had the lowest temperature gap between ground surface and 5cm underground compared with CB and CK when temperature was higher at 14：00.The temperature difference between surface and subsurface 5cm was the largest in summer,minimum in winter.Variation of soil water content and air relative humidity was similar,performing as that soil moisture content of mixed forest was higher than that of pure forest.In general,the ability of mixed forests to improve the microclimate is better than that of pure forests with respect to lowering and stabilizing air temperature and soil temperature,increasing air humidity and soil water content.