Canopy gaps are the origin of forest succ ession. The gap features affec t the distribution of the environmental factors (such as light, temperature an d humidity) which in turn influence forest structure, species composition and fo rest dynamic. Air temperature measurements were conducted in the secondary fores t canopy gaps of Xishuangbanna at wet-hot season(July). The air temperature dis tr ibution of the canopy gaps is discussed. The results show that the daily variation in air temperature has 2 to 3 peaks at the different sites (4 azi mut h) in the tropical secondary forest gaps and the daily mean air temperature rank s in the order of gap edge ＞expended gap edge ＞forest interior. Daily ran ge of air temperature is not significant. Contrasted with the center of gap, th e other sites are of increasing minimum temperature and decreasing maximum one. The increment of 0.4～0.6℃ is weaker than the decrement of -1.4～-1.5℃. The resul ts supply a research basis for understanding the microclimatic formation of cano py gaps, the succession and regeneration of forest community.%林窗是群落演替的起始地，其本身的特征影响着环境因子，进而影响森林的结构、物种组成 、种群动态等.利用西双版纳湿热季次生林林 窗的实测气温资料，探讨该林窗气温的分布特征.结果表明：热带次生林林窗4个方位不同 位置的气温日变化具有2～3个峰值；日平均气温的高低顺序是林窗边缘＞扩展林窗边缘＞林 内；林窗内气温日较差较小；林窗内不同位置相对林窗中央具有增加低温和降低高温的效应 ，这种增温效应(0.4～0.6℃)较降温效应(-1.4～-1.5℃)弱.其结果可为林窗小气候形 成机制及森林群落的演替与更新等提供科学依据.
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