不同年龄灰木莲人工林对林内小气候的影响

Influences of Manglietia glauca Plantations of Different Ages on the Microclimate in Them

人工林小气候效应是森林生态系统研究的重要内容之一.在广西南宁市北郊的高峰林业示范基地内,选择代表性的3种不同年龄灰木莲人工林设置样地,分别对主要气象要素进行对比观测.结果表明:(1)3,8和46年生灰木莲林内太阳辐射能日平均值依次为12.53,6.09和2.44w/m2,随着林分年龄的增大,林内的太阳辐射能显著减少.(2)3,8和46年生灰木莲林内空气温度依次为24.1℃、23.9℃和23.4℃,随着林分年龄的增大,林内空气温度逐渐降低.(3)3,8和46年生灰木莲林内地面温度依次为23.6℃、21.8℃和21.3℃,随着林分年龄的增大,林内地面温度逐渐降低.(4)3,8和46年生灰木莲林内空气相对湿度依次为80%,86%和85%(RE值),随着林分年龄的增大,林内的增湿作用明显.研究结果表明,当灰木莲人工林恢复到8年生时,其林内的空气相对湿度与相同类型的成熟林相当,但削减林内太阳辐射能以及降低林内空气温度和地面温度的效果尚未达到成熟林的水平.

Eco-microclimatical effects of plantations are an important aspect in researches of the forest ecologi cal system. Sample plots were set in Manglietia glauca plantations differing in stand age at the Gaofeng For estation Base located in the north of Nanning, and the main meteorological elements were observed and com pared. The results showed that in 3-, 8-, and 46-year-old M. glauca forests, mean daily solar radiation was 12.53,6.09 and 2.44 w/m2 , respectively, indicating that solar radiation within the plantations signifi- cantly decreased with increasing stand age; that air temperature was 24.1, 23.9 and 23.4 ℃, respectively, indicating that air temperature within the plantations decreased with increasing stand age; that surface temperature was 23.6, 21.8 and 21.3 ℃, respectively, i.e. dropping gradually with increasing stand age; and that relative humidity （RH） was 80, 86 and 85%, respectively, showing an obvious humidification effect. The above results suggested that when a Manglietia glauca plantation recovers to eight years, rel ative air humidity in it will be comparable to a mature grove of the same type, but its effect of reducing ra diant energy, air temperature and surface temperature are not as great as the mature grove.