哀牢山亚热带常绿阔叶林地温特征及变化趋势

Characteristics and trend of soil temperature in subtropical evergreen broad-leaved forests in Mt. Ailaoshan

地温是森林气候的重要指标,对于植物生长和土壤呼吸具有重要作用。本文利用中国科学院哀牢山亚热带森林生态系统研究站(ASSFE)林外和林内的长期地温观测资料,对研究较少的地温多年平均特征和长期变化趋势进行了研究。结果表明:哀牢山亚热带常绿阔叶林具有较强的生态气候功能,林内外年平均地表温度的差异为2.4℃(林内年平均最高地表温低于林外13.4℃,林内年平均最低地表温高于林外3.4℃),干季的林内外差异大于雨季;年平均地表温具有上升的趋势,干季强于雨季,林内强于林外(林外:0.010℃/a,林内:0.017℃/a)。因此,地温的总体水平上升,地-气温差、林内与林外的地温差缩小。受此影响,哀牢山亚热带山地常绿阔叶林的分布海拔将会升高;地温的升高将加速土壤呼吸速率,进而影响区域内的碳平衡。

Soil temperature is an important factor affecting plant growth and soil respiration.We analyzed the long-term data of soil temperature in the open areas and interior forests observed at the Ailaoshan Station for Subtropical Forest Ecosystem Study（ASSFE）.Compared with open areas,interior forests had a lower mean soil temperature（by 2.4℃）,a lower mean maximum soil temperature（by 13.4℃） and a higherminimum soil temperature （by 3.4℃）,which implies a strong canopy shading effect on soil temperature.The difference between soil temperature inside forests and in open areas was higher in dry seasons than in wet seasons.Soil temperature increased with a stronger trend in dry seasons than in wet seasons.Soil temperature of interior forests had a stronger rising trend（0.017℃/year） than in open areas（0.010℃/year）.In conclusion,soil temperature is generally rising,while the difference of soil temperature and air temperature is decreasing,and so is the soil temperature difference between open areas and interior forests.Consequently,the distribution elevation of subtropical montane evergreen broad-leaved forest will be driven upward by the trend of warming,and carbon balance and soil respiration will be inevitably disturbed as a result of rising soil temperatures.