中国西南地区热带季节雨林及山地常绿阔叶林热值及能量分配格局

 能量分配格局是研究生态系统能量流动的基础，但是由于热带森林结构的高度复杂性和物种多样性，对它的热值和能量分配格局的全面研究还 很少。该文研究的热带季节雨林位于西双版纳，是分布于热带亚洲北缘的一种森林类型；山地常绿阔叶林位于云南省中部的哀牢山，属于我国 西部亚热带地区的山地常绿阔叶林。该研究的目的是探讨这两种重要森林类型的热值和能量分配格局，验证Golley（1961，1969）提出的世界 范围内植被的热值由低纬度向高纬度、由低海拔向高海拔升高的规律。热值的测定采用SDCM-Ⅲa氧弹测量仪。两个森林样地面积都是1 hm²，能 量分配格局及年固定量根据生物量和生物量增量计算。研究结果表明，热带季节雨林样地的热值低于山地常绿阔叶林，乔木层的热值>灌木层> 草本层，所有器官中叶片的热值较高。由于以前种植砂仁（Amomum villosum）的影响，热带季节雨林样地的能量现存量小于山地常绿阔叶林， 但是因为地处高温高湿、光照充足的地区，热带季节雨林的能量年固定量高于山地常绿阔叶林。对于热带季节雨林样地来说，97％的能量储存 在乔木层中；山地常绿阔叶林样地的乔木层储存了88％的能量，可见乔木层是维持森林能量结构的关键层。研究结果为Golley的结论提供了更 加丰富的实验证据。

CALORIC VALUES AND ENERGY ALLOCATION OF A TROPICAL SEASONAL RAIN FOREST AND A MONTANE EVERGREEN BROAD-LEAVED FOREST IN SOUTHWEST CHINA

Aims Energy allocation pattern is the basis for understanding energy flow processes in ecosystems. High structure complexity and species diversity of tropical forests, however, have resulted in little research on caloric values and energy allocation patterns in tropical rain forests. Tropical seasonal rain forest (TSRF) in Xishuangbanna, Southwest Yunnan is distributed on the northern edge of tropical Asia, and montane evergreen broad-leaved forest (MEBF) is located in subtropical mountain areas of middle Yunnan. Our objectives are to examine the energy allocation pattern of the two forests and test the hypothesis of Golley (1961, 1969) that caloric values of vegetation tend to increase with the altitude and latitude.  Methods Caloric values were measured with a SDCM-Ⅲa oxygen bomb calorimeter. Energy allocation and sequestration were estimated based on biomass and biomass increment in a 1 hm² plot in each forest.  Important findings The caloric value of the TSRF plot was lower than that of the MEBF plot. Caloric values decreased from tree layer to shrub layer to herb layer. Leaves showed the highest caloric values of any plant part. Due to an understory plantation of Amomum villosum, which had removed almost all saplings and seedlings, the TSRF plot stored less energy than the MEBF plot, although it still maintained a high energy sequestration rate for tropical habitats with high temperature, humidity and intensive solar radiation. The tree layer stored 97% of the energy in the TSRF plot and 88% in the MEBF plot, suggesting that tree layer plays a key role in the maintenance of energy structure in the two forests. Our results support Golley’s hypothesis.