<正>选择不同的林分类型和立地条件。按不同经营密度分别设立固定标准地-对天然杨桦林林分生长性状（树高、胸径、材积等）、形质指标（冠长、冠宽等）、_}【三能利用、养分及林内土壤水分变化等进行连续的定位观测。在立地分类基础上，定量分析了经营密度对林分干物质积累量、养分归还量、林地土壤分水量、林分生长及出材量的效应。结果表明：经营密度对林分生长、干物质积累、枯枝落叶分解和土壤结构的改善具有较大影响。天然杨桦林单株叶量随经营密度增大而减少。单株叶片总面积、林分平均冠长、冠幅则以中等经营密度最大；凋落物分解率随密度增大而减少，营养元素归还量以中等经营密度为最大；密度相同，不同土层深度的土壤含水量均随土层深度增加而减少，同一土层深度的土壤含水量随经营密度减少而降低；山杨林和白桦林单位面积胸径年生长量随经营密度的增加而减少；林分蓄积以中等经营密度最大。

Pulping black liquor treated by the extremophiles from sludge of black liquor pool was discussed. The influence of anaerobic decomposition by the process conditions such as black liquor, sludge (V/V), black liquor concentration, pH and temperature was discussed. The results showed: T=30~35℃, pH=6.5~7.2 was the optimal process condition. The ratio of removal organic was rather high. In addition, anaerobic decomposition of aldonic acid was adapted for the condition of high temperature and stronger acidity (T>50℃, pH<6). Moreover, parts of high-molecular lignin was degraded in the biological reaction.