小兴安岭三种林型叶面积指数的估测

利用Winscanopy2006冠层分析仪测定2009年7月初至11月初小兴安岭白桦次生林、谷地云冷杉林、阔叶红松林的有效叶面积指数(LAI_e)，并将经过木质部分所占比率、冠层水平集聚和簇内集聚校正的11月初LAI_e作为真实叶面积指数(LAI_t)，结合凋落物法测定3种林型的LAI_t及其季节动态.结果表明： 调查期间，白桦次生林的LAI_e在7月达到峰值(2.21)，谷地云冷杉林、阔叶红松林的LAI_e在8月达到峰值，分别为2.57、2.68.白桦次生林、谷地云冷杉林、阔叶红松林的LAI_t均在7月达到峰值，分别为3.44、3.86、6.93；相对于本文探讨的方法，光学仪器所测定的LAI_e在最高叶面积指数期分别低估33.1%、32.9%、66.0%；而在整个调查期内，谷地云冷杉林和阔叶红松林LAI_e平均低估22.8%和56.5%，白桦次生林平均高估13.2%.

Conformity degree evaluation of urban ecological river:A case study in Shanghai

From early July to early November 2009, the effective leaf area index (LAI_e) of secondary Betula platyphylla forest, spruce-fir valley forest, and mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains were measured with Winscanopy2006 Plant Canopy Analyzer, and the LAI_e measured in early November and calibrated with the woody to total ratio as well as the clumping index (for clumping beyond the shoots) and the needle to shoot area ratio (for clumping within the shoots) was derived as the true leaf area index (LAI_t). In combining with litterfall method, the LAI_t and its seasonal dynamics of the three forest types were estimated. The LAI_e of the secondary B. platyphylla forest reached its peak in July, with a value of 2.21, and that of the spruce-fir valley forest and mixed broadleaved-Korean pine forest peaked in August, with the values of 2.57 and 2.68, respectively. All the three forest types had the highest LAI_t in July, with the values of 3.44, 3.86, and 6.93 for the secondary B. platyphylla forest, spruce fir valley forest, and mixed broadleaved Korean pine forest, respectively. In comparison with the method proposed in thisstudy, the peak time LAI_e of the secondary B. platyphylla forest, spruce-fir valley forest, and mixed broadleaved-Korean pine forest obtained by the optical instrument method was underestimated by 33.1%, 32.9% and 66.0%, respectively, and the LAI_e of the three forest types in the entire study period was underestimated averagely by -13.2%, 22.8%, and 56.5%, correspondingly.