STUDY ON THE PHYSICO-MECHANICAL PROPERTIES OF CHINESE FIR (Cunninghamia lanceolata)IN YUNNAN

According to test results, the density of wood and the parallel compressive strength of Chinese fir grown in the South-east of Yunnan are the smallest, the ones in the central are larger and the ones in the South-west the largest. The bending strength of timber grown in the central is the smallest, next is the one in the South-east, and the one in the South-west is the largest. The modulus of elasticity of timber grown in central region is smaller, and the similar in the Southeast and South-west. The toughness of the wood grown in central region is the smallest, next comes the one in the South-west, and the largest is the one in the South-east. In a word, differences of physico-mechanical properties in these three cultivated regions are not large. The density and strength of Chinese fir grown in a sun slope are larger than those grown in a shade slope in the same cultivated region, and the differences of physico-mechanical properties of Chinese fir grown in different slope directions are larger than those grown in the same slope direction in different cultivated regions, The density and strength of the Chinese fir of seedings are larger than those grown out of cuttings.