长白山自然保护区叶面积指数测量及结果

MEASUREMENT OF LAI IN CHANGBAI MOUNTAINS NATURE RESERVE AND ITS RESULT

叶面积指数(LAI)是一个重要的生物结构参数,但是大范围叶面积指数的获取比较困难。当前遥感技术为大范围叶面积指数的测量提供了条件,但遥感得到的叶面积指数需要进一步的地面验证。因此实地叶面积指数的获取具有重要意义。叶面积指数实地测量方法包括直接测量方法和间接光学测量方法,由于直接测量方法具有局限性,而光学测量方法中集聚效应又很重要,该研究采用了考虑集聚效应的光学测量方法,通过观测和计算,长白山自然保护区主要植被类型的叶面积指数分别是:红松阔叶林7 7,云冷杉林6 6,阔叶林3 9,岳桦林3 4。在测量结果的基础上,分析了不同植被类型的叶面积指数的分布情况。通过对实际叶面积指数和有效叶面积指数的比较和分析,发现集聚效应对于使用光学测量方法测量叶面积指数有重要影响。

Leaf area index (LAI) quantifies the amount of foliage area per unit ground area. Therefore, it is an important parameter controlling many biological and physical processes associated with vegetation on the Earth's surface. It is also an important surface parameter that is required in the studies of climate change, atmosphereecosystem interaction. With the development of Remote Sensing technique, the measurement of LAI in large area which is previously difficult can be satisfied, but the LAI calculated from the Remote Sensing requires groundbased validation. So the groundbased measurement of LAI is very important. In our experiment we have measured the LAI in Changbai Mountain using the optical method taking clumping effect into account because of the limitation of the direct measure and the importance of the clumping effect in the optical method. According to the measurement, LAI for Korean pinebroadleaved forest, sprucefir forest, broadleaved mixed forest, Betula ermanii forest is about 77, 66, 39, and 3.4, respectively. Based on the measurement result, the LAI distribution for different vegetation types is analyzed. LAI range for different vegetation type is different. Through the comparison and analysis of the effective LAI and true LAI, it concludes that clumping index is important in the calculation of the LAI using the optical methods. Finally, the problem in the measurement is discussed. The measurement using LAI2000 and TRAC together is suggested. The measurement result offers the information for the LAI inversion in Remote Sensing.