2种短周期工业用材林种植恢复过程对林内小气候的影响

Effect of Plantation and Reestablishment of Two Short-Cycled Types of Industrial Timber Forests on Forest Micrometeorology

在广西南宁市北郊的杉木林采伐迹地上,经过炼山清理,营造厚荚相思林和尾巨桉林以及灌草坡自然恢复3种植被类型,分别对主要气象要素进行连续4a的对比观测。结果表明:(1)厚荚相思林和尾巨桉林内太阳辐[射]照度日平均值分别为126.6和90.8W.m-2,分别占灌草坡植被的50.4%和36.1%;并随着林龄增大林内太阳辐[射]照度呈波浪式下降趋势。(2)厚荚相思林和尾巨桉林内年平均空气温度和地面温度分别比灌草坡植被降低0.7～0.8和1.8～2.7℃,并随着林龄增大温度逐渐降低。2种林分各年份空气相对湿度比灌草坡植被提高1～3百分点;并随着林龄增大而使林分内的增湿作用越明显。(3)2种短周期工业用材林种植恢复到5年生时,对林内小气候的调节作用已达到了成熟林分的水平,且厚荚相思林优于尾巨桉林。

The study on effect of afforestation on forest micrometeorology has important implication for understanding forest ecosystems. A four-year study was carried out to observe and compare variation of the micrometeorology of three types of vegetation, i.e. Type A （Acasia crassicarpa forest）, Type B （Eucalyptus grandis ×E. urophylla forest）, and Type C （ shrubbery ＋ grasses） established on burned clearings of fir forests in the the northern suburbs of Nanning in Guangxi. Rresults show that （ 1 ） the average daily solar radiation of Type A and Type B was 126.6 and 90.8 W · m^-2, respective- ly, equaling to 50. 4% and 36. 1% of that of Type C, and declining with the age of the forests in a wave pattern ; （2） the annual mean air temperature and ground temperature inside the two stands was 0. 7-0. 8 and 1.8-2. 7 ℃lower than on the shrub-grass land, and getting lower with the age of the stands ; and the annual mean relative humidity of the air in both forest stands increased by 1-3 percentage points over that in the shrub-grass land, and the effect got more evident with the age of the stands ; （ 3 ） the two short-cycled industrial timber forests, 5 years in age, showed full effects like mature forest stands on the micrometeorology therein, and the effect of Acasia crassicarpa forest was more obvious than that of Eucalyptus grandis × E. urophylla forest.