1990—2010年长白山温带针阔叶混交林生长季及积温的变化

长白山温带针阔叶混交林作为典型的温带森林生态系统，对气候变化的反应比较敏感，其生长季及积温的变化是准确评价该我国东北林区气候变化的重要依据。本研究采用中国科学院长白山森林生态系统定位站获取的1982-2010年气温目值观测资料，分析了近20a该地区生长季长度及积温的变化，结果标明长白山温带针阔叶混交林29a的平均温度为3．6℃，29a中该地区气温有较弱的上升趋势；长白山温带针阔叶混交林1990-2010年生长季长度的平均值为174d，近20a中生长季长度呈弱增长趋势；长白山温带针阔叶混交林1990～2010年生长季起始日期变化较稳定，生长季终止日期有推后的趋势；长白山温带针阔叶混交林1990-2010年≥5℃的活动积温和有效积温平均值分别为2616．9℃、1744．8℃。近20a中，≥5℃活动积温和有效积温都有着缓慢升高的趋势。

Variation of the Growing Season and Temperate Mixed Forest in Changbai Accumulated Temperature for Mountains During 1990-2010

As a typical temperate forest ecosystem, the response of Changbai Mountain temperate mixed forest to climate change is very sensitive. Analysis of the changes in growing season and accumulated temperature are very important for evaluating accurately climate change in this area. In this study, based on the daily data obtained from the Opened Research Station of Changbai Mountain Forest Ecosystem, Chinese Academy of Sciences during 1982-2010 ,the changes of growing season and accumulated temperature in this forest ecosystem were analyzed. The results show that the mean annual air temperature rose weakly in the last 29 years and the annual mean air temperature was 3.6 ℃ ;the mean length of growing season in this ecosystem was 174 d,which increased weakly from 1990 to 2010;the change in initial date of growing season was stable, but the ending date of that prolonged gradually during the research period; the mean value of active accumulated temperature and effective accumulated （≥5 ℃） was 2 616.9 ℃, 1 744.8 ℃ respectively from 1990 to 2010, which both increased slowly.