杭州常绿阔叶林对林内近地层温度和湿度的调节效应*

1990～1991年，观测了杭州风景区天然常绿阔叶林内的温度和湿度，并以此与杭州市气象台的同期气象资料进行对比分析。其结果表明:天然常绿阔叶林对林内地表温度的调节效应最为显著，林内年平均温度比市区下降2.6～3.3℃，年平均最高温度下降12.1～13.2℃，年极端最高温度下降25.3～29.4℃；使年平均最低温度上升1.2～1.4℃，年极端最低温度上升7.9～8.0℃；使平均日较差下降13.3～14.6℃。对林内5～20cm深度地中温度的调节作用也甚为明显，可使年平均温度比市区下降2.0～3.0℃。对地表、地中温度的降温效应都以盛夏午后14:00前后最为显著，在严冬季节具有一定的增温效应。对林内近地层气温的调节趋势与地温基本一致，但调温幅度比地温小。可使林内近地层空气的年平均绝对湿度比市区提高0.5～0.6hPa，年平均相对湿度上升7%～8%，且都以午后14:00前后增湿最为明显。

Effect of Broadleaved Evergreen Forest in Hangzhou on Temperature and Humidity in the Forest

During 1990~1991, temperature and humidity in the natural braodleaved avergreen forest were measured in the scenic spot of Hangzhou and were compared with the data in the same period from Hangzhou Meteorological Station. The results showed that this kind forest had the most remarkable effect on the ground surface temperature within the forest. The forest decreased the annual everage temperature, the annual average maximum temperature and the annual average extreme maximum temperature of the ground surface by 2.6~3.3℃, 12.1~13.2℃, and 25.3~29.4℃ respectively. Meanwhile, it inereased the annual average minimum temperature and the annual average extreme minimum temperature of the ground surface by1.2~1.4℃ and 7.9~8.0℃. The daily range of the surface temperature in the forest was lower than that in the urban district of Hangzhou. The forest had a noticeable effect on the soil temperature below the ground surface, and it could lower the annaul average temperature by 2.0~3.0℃. The most obvious decrease of the surface temperature and the soil temperature appeared at 14:00 in summer, and in winter, there was an increase of the temperature in the forest to a certain extent. Air temperature changes in the forest had the same tendency with those of the soil temperature, but fluctuated within a narrow range. Annual average absolute humidity and relative humidity of ground layer in the forest were higher than those in the urban district of Hangzhou by 0.5~0.6 hPa and 7%~8%, and the effect of increasing humidity occurred most obviously at14:00.