窿缘桉防护林小气候的初步研究

Microclimates of Eucalyptus exserta shelter forests

对广西北热带山口林场２ 种林龄窿缘桉防护林内及空旷地的主要气象要素进行定位对比观测。结果表明： １５ 年生和４５ 年生窿缘桉林内的平均太阳辐射日总量分别为２４６ ×１０３ ｋ Ｊ·ｍ － ２ 和２０２ ×１０３ ｋ Ｊ·ｍ － ２ ， 分别比空旷地（５４３ ×１０３ ｋ Ｊ·ｍ － ２）减少５４７ ％ 和６２８ ％ ； 平均气温分别低０２ ℃和０７ ℃； ０ ～２０ ｃｍ 土层的平均温度分别低１３ ℃和１８ ℃； 平均空气相对湿度高１ ％ 和３ ％ ； ４５ 年生林内的平均风速降低８２４ ％ 。表１

The meteorological factors inside two different ages of Eucalyptus exserta shelter forests and in open area were contrasted at fixed positions in Shankou Forest Farm in the north torrid zone,Guangxi.The results showed that the mean daily gross energy of solar radiation inside 1 5 year old stand and 4 5 year old stand was 2 46×10 3 kJ·m -2 and 2 02×10 3 kJ·m -2 respectively,which were 54 7% and 62 8% lower than that in open area(5 43×10 3 kJ·m -2 )respectively.Mean air temperature was 0 2℃ and 0 7℃ lower respectively,mean temperature of 0～20 cm soil layer 1 3℃ and 1 8℃ lower respectively,mean air relative humidity 1% and 3% higher respectively and mean wind speed(4 5 year old stand)82 4% lower than that in open area.