哀牢山亚热带常绿阔叶林土壤温度时空分布对模拟增温的响应

The response of soil temperature to experimental warming in a subtropical evergreen broad-leaved forest in Ailao Mountains,Yunnan,SW China

为把握森林不同深度的土壤温度对区域气候变暖的响应,评估气候变暖对亚热带森林土壤呼吸的影响,利用在哀牢山亚热带常绿阔叶林中设置的土壤增温和土壤呼吸人工控制实验,对2011—2013年的对照样地和增温样地不同深度的土壤温度实测数据进行了分析,结果表明:区域气候变暖导致的温度升高不改变土壤温度的年变化和日变化特征;干季的增温效应大于雨季;同一深度增温效应具有一定的年变化,但日变化不明显;增温效应在土壤表层较大,1—4月明显,2月最高,增温可达3℃;5 cm深度的平均增温效应在2℃左右,且年变化较小;随着深度的增加,增温效应呈现对数降低趋势;如果以0.5℃为增温效应的阈值,推算可得出:干季的影响深度为3.82 m,雨季可达12.04 m,年均为6.58 m。

To improve our understanding of responses of soil temperature to global warming in for-ests, we conducted a soil warming experiment in a subtropical evergreen broad-leaved forest inAilao Mountains, Yunnan, SW China. Based on measurements from 2011 to 2013, we examinedwarming effects on seasonal and diurnal patterns of soil temperature. The results showed that war-ming effects in dry season were greater than in rainy season, showing seasonal variations, but notdiurnal variations. Soil-surface temperatures increased between January and April, with a 3 ℃maximum in February. Warming increased soil temperature by 2 ℃ at the soil depth of 5 cm. Thewarming effect decreased exponentially with soil depth. Based on a 0.5 ℃ temperature increase,soil warming could reach the depth of 3.82with an annual mean of 6.58 m.m in the dry season, 12.04 m in the rainy season,with an annual mean of 6.58 m.