Intratree Variability of Cleavage Resistance of Chinese Fir from Plantation

INTRODUCTION Chinese fir (Cunninghamia lanceolata) is a very important timber species in the southern China (Shi Jisen et al. 1987). It is good, fast-growing, and exempts from serious plant diseases. Its plantation is big in terms of size in the South of China and its storage stock is very rich, which is about 20% of the national commodity wood (Zhou Shuangquan et al. 2000). And the lumber becomes mainly commercial construction materials in China because of straight grain, light and so…

Intratree Variability of Cleavage Resistance of Chinese Fir from Plantation

This paper studied the variation of cleavage resistance of Chinese fir wood from plantation. Six trees of 36 years old were investigated, and the cleavage resistance properties for 672 samples made of the trees were tested. The samples were cut from the sapwood and heartwood at different directions (south and north) and heights (1.3, 3.3, 5.3 and 7.3 m) of the trees. The result showed that: tangential cleavage resistance was higher than radial one, and cleavage resistance of sapwood was higher than that of heartwood, but there was no significant difference in cleavage resistances between sections of the north and the south of the trees. There was a little variation in cleavage resistance between the radial and tangential from butt to top log, which shows a little decrease with the height from 1.3 to 5.3 m , but a rise in the top of the trees.