选取内蒙古大兴安岭地区和呼和浩特市兴安落叶松、油松、樟子松和白杄4种典型针叶林，利用PC-2型太阳辐射记录仪进行UVB辐射日进程测定，以获得4种典型性针叶林的UVB屏蔽效应；对4种林分UVB屏蔽效率与枝下高、郁闭度等冠层特征因子进行相关分析。结果表明，（1） 4种林分对UVB辐射均产生显著消减作用，其屏蔽效应分别为：落叶松（91.2%）、白杄（90.2%）、油松（88.9%）、樟子松（88.2%）；但林分类型和时间段的不同对UVB的屏蔽效应均无显著影响。（2） UVB屏蔽效应与林分郁闭度呈正相关关系，相关系数0.635，与冠层呈负相关关系，相关系数0.966，而与林分平均树高，平均枝下高相关性不显著。
The four familiar species of conifer forest in Inner Mongolia i.e. Larix gmelini, Pinus tabulaeformis, Pinus sylvestris, and Picea meyeri were chosen as the investigative objects in forest area of Daxinganling Mountain and Hohhot City. The UVB radiation values were measured under the shade conditions and in the sunshine by using PC-2 solar radiation sensors. The UVB Shielding efficiency of examined tree species was calculated. The difference of UVB screening efficiency was compared with. And using the Pearson correlation analysis method, the UVB screening effect of different forest and its related characteristics, such as average canopy diameter, coverage, average height, and average bifurcate height, were concluded. The results show that: (1) Distinct weakening effect is achieved in the four familiar species of conifer forest. The UVB shielding efficiency for Larix gmelini is 91.2%, for Pinus tabulaeformis is 88.9%, for Pinus sylvestris var. mongolica is 88.2%, and for Picea meyeri is 90.2%, respectively. However with the different forest and time, their effects on the UVB shielding efficiency are insignificant. (2) There is a significantly positive correlation between the UVB shielding efficiency and coverage. There is a significantly negative correlation between the UVB shielding efficiency and average canopy diameter. There is an insignificant correlation between the UVB shielding efficiency and the average height of plant, and the average bifurcate height of plant.
