<正>以材性优良的毛竹等竹种为参比，研究了丛生竹种大木竹竹材的物理性能。结果表明：大木竹竹材的基本密度为0.618g/cm3。小于毛竹的基本密度（0.765g/cm3），而比参比的其他丛生竹密度大或与之相当；大木竹竹材气干体积干缩率为7.7%，吸水饱和『本积湿胀率为18.686%。饱湿含水率为77.8%。均大于毛竹材的相应值。

Biomasses of Hippophae rhamoides L. in semi-arid and semi-humid area of north-west China had been widely measured with the method of harvesting of standard trees in sample plots. The results show that the biomass varied greatly between different areas due to the differences of climatic and soil conditions. Within the biomass of total tree, the allocation in trunk increases firstly and then decreases, and it in branches conserves relative stable, while it in leaves decreases with the age of trees. The ratio of stem/root of biomass increases with the age of trees and is positively related to the precipitation of different zones. The distribution of roots in soil is generally shallow and there is about 65.66%~79.95% of roots concentrated in top soil of φ~15 cm and the biomass allocations in roots of φ>4cm and φ=1~2 cm take about a half of the total roots. The allocation of root length in thin roots of φ<0.5cm is about 64.894%~80.09% of total. The root nodules grow mostly on trees of 6~10 year old and are mostly distributed on roots of φ<1.0cm and in top soil of 0~15cm. In addition, the above-ground biomass of H. rhamoides can be estimated with both growth-factor model and site-factor model. Among the influencing factors of biomass, the zonal climatic and soil factors affect strongly and then is aspect and location of slope, except the factor of gradient of slope.