The planting density experiment consists of four density treatments: 1 620 trees/hm2,2 475 trees/hm2,2 925 trees/hm2,and 3 510 trees/hm2.The density experiment stands of Chinese fir were investigated in Nanling hilly area of high site index stands.
Above ground biomass of 33 Chinese fir trees in a hilly region of Southern Jiangsu aged 2-18 years have been investigated by "divided-storeys" method. After being compared with other methods of estimation, the regression equations showing the relationship between Chinese fir breast height diameter and stem weight(W,), branch weight(W2), needle weight(W3) have been established as follows:
Nutrient cycling was studied over a 3-year period beginning in 1979 in a typical Chinese fir plantation in the hilly area in central Guangxi Province. The results are as follows:1. In the 8.5-years-old Chinese fir plantation, total biomassand productivity (during the last 3 years, 1979—1982)were 65—78 ton/ha and 15.8ton/ha/yr, respectively. Total accumulation of elements was estimated to be 700 kg/ha, of which nitrogen 287.6 kg/ha, phosphorus 10.1 kg/ha, potassium 143.0 kg/ha, calcium 137.4 kg/ha and ...
D. B. H. growth will be accelerated greatly if timely and properly thinning is carried out in the forest stands of Cunninghamia lanceolata Thinning will also affects the height growth during the tree's fast growing period in height, but not after the period. Rational thinning can raise the wood output per unit area; the wood output of the test plantation was increased by 31.20-40.65ms/ha at the age of 13, as compared with the control. It has been proved when practising improvement thinning on the hilly$$...