COMPARATIVE STUDY ON PHYSICAL AND MECHANICAL PROPERTIES OF DIFFERENT FAST-GROWING CLONES OF CUNNINGHAMIA LANCEOLATA

The objective of the current study was to compare, the wood properties of different Chinese wood verities to provide information for the rational use of wood and the directional cultivation of high quality wood. For this purpose a total of 7 excellent clones of 30-years old Chinese fir wood that were 79172, 8219, 7962, 79182, 79173, 7922, and 7911, respectively were taken to compare with one control (CK) wood collected from Jindong Forest Farm in Hunan Province. The air-dry density, basic density, modulus of rupture (MOR), modulus of elasticity, compressive strength parallel to grain, tensile strength parallel to grain, compression resistance of all stripes to flat & radial and compression resistance of local to flat & radial were measured according to national standards. Air-dry density, basic density, chord-wise cross-grain compression, all radial cross-grain compression, chord cross-grain local compression, radial cross-grain local compression, along-grain bending strength, along-grain resistance The measured values of flexural modulus, compressive strength along the grain, and tensile strength along the grain are 0.376-0.438 g/cm3, 0.301-0.355 g/cm3,5.18-7.16Mpa,4.64-6.27Mpa, 9.68-10.99MPa, 9.18-10.66MPa, 64.34-79.38 Mpa,7.78-8.95Mpa,42.78-50.20MPa,93.72-114.69 MPa; the corresponding maximum values are 79173 (0.463 g/cm3),79182 (0.355 g/cm3),79172 (7.16Mpa),79172 (6.27 Mpa),7922 (10.99MPa),79172 (10.66 MPa),79182 (179.38 Mpa),79182 (8.95 Mpa), 79172 (50.20 MPa), 79172 (114.69 MPa). In the physical and mechanical properties of wood, the air-dry density, basic density, chordwise transverse grains are all compressive, radial transverse grains are all compressive, chord transverse grains are locally compressive, radial transverse grains are locally compressive, and along grains of flexural strength, along-grain flexural modulus, along-grain compression and along-grain tensile are significantly different among different strains and are closely related. Using 10 indicators of wood physical and mechanical properties for cluster analysis, the wood properties of 79172 and 7922 are generally better than other varieties.