| In this study, we analyzed wood from Phoebe zhennan (family Lauraceae) to identify its particular characteristics and properties. Samples were obtained from P. zhennan growing in Lushan County (Ya'an) and Xinjin County (Chengdu) in Sichuan province. We examined the macrostructure and microstructure of P. zhennan wood, and screened for differences in structural parameters such as density, hygroexpansion, thermal conductivity andmechanical property. Samples were obtained from living tree new material from P. zhennan growing in Jinfeng Temple (Ya'an) and P. zhennan ancient buried wood (Ya'an) in Sichuan province. We examined the macrostructure and microstructure of P. zhennan wood.At the same time we compare these samples were obtained from P. zhennan growing in Lushan County, Xinjin County and ancient buried wood in terms of density, hygroexpansion, thermal conductivity andmechanical property.Through the handheld microscope, optical microscope and scanning electron microscope were taken contrast in different regions and different types of P. zhennan macrostructure and microstructure.The slice method under optical microscope were measured per unit area of pipe hole number and tube hole length, width and lumen diameter, the segregation process under the optical microscope determination of the pipe length, and wood fiber length, width and lumen diameter.The ratio of length to width, ratio of wall to cavity and cavity diameter of the pipe hole and the wood fiber were calculated. And we study on the radial variation from heartwood to sapwood packet number.According to the relevant national standards, the physical properties of wood such as dry density, air-dry density, basic density, dry shrinkage coefficient and so on were measured.The thermal conductivity of wood was measured by TC3000 type thermal conductivity meter.Mechanical strength, such as compressive strength, bending strength and hardness of wood, were studied by universal mechanical testing machine. The results showed that:(1) At the macroscopic level, P. zhennan wood from Lushan was yellowish brown, tinged with green, wood surface gloss was weak and had a herbal fragrance; P. zhennan wood from Xinjin was dark brown, tinged with green, wood surface gloss strong and had a sweet fragrance. P. zhennan wood from Jinfeng Temple was pale yellow, wood surface gloss was weak and had a refreshing fragrance; P. zhennan ancient buried wood was blackish green, wood surface gloss strong and had a medicine fragrance.(2)At the microscopic level, P. zhennan wood from Lushan, P. zhennan wood from Jinfeng Temple and P. zhennan ancient buried wood were diffuse-porous, while that from Xinjin was diffuse-porous to semi-diffuse-porous. Cross section of catheter was round or oval;intervessel pitting alternately tissues were type II or type III heterogeneous.(3)P. zhennan wood from Lushan and P. zhennan wood from Xinjin age closed, belonging to the juvenile wood, the growth status was not stable, so parameters of the catheter and wood fiber parameters were with the age increased showed a "wave" variation pattern;P. zhennan wood from Jinfeng Temple and P. zhennan ancient buried wood belonged to the hundred years of timber, relatively stable growth.Because of P. zhennan ancient buried wood undergroundfor many years, affected by the outside world.The shape of the catheter and the wood fiber were changed and tended to be consistent.Therefore, the parameter ofcatheter and wood fiber with the increase of age showed a "wave", and was smaller than the P. zhennan wood from Jinfeng Temple.(4)P. zhennan wood from Lushan air dry density, basic density, volume shrinkage coefficient were 0.552g/cm3,0.464 g/cm3,0.095%; P. zhennan wood from Xinjin air dry density, basic density, volume shrinkage coefficient respectively were 0.579g/cm3,0.489 g/cm3,0.107%; P. zhennan ancient buried wood air dry density, basic density, volume shrinkage coefficient respectively were 0.531 g/cm3,0.435 g/cm3,0.444%.The P. zhennan ancient buried wood density was the smallest, but the volume shrinkage coefficient was far greater than the P. zhennan wood from Lushan and P. zhennan wood from Xinjin.The P. zhennan ancient buried wood was more prone to cracking and warping.(5)P. zhennan wood from Lushan in cross section, radial section and tangential section of the heat conduction coefficient were 0.210W/m*K,0.161 W/m*K,0.183 W/m*K. P. zhennan wood from Xinjin in cross section, radial section and tangential section of the heat conduction coefficient were 0.221 W/m*K?0.153 W/m*K?0.190 W/m*K.The P. zhennan ancient buried wood in cross section, radial section and tangential section of the heat conduction coefficient wereO.187 W/m*K?0.178 W/m*K?0.181 W/m*K.The thermal conductivities of wood from Lushan and Xinjin were similar, The cross section and tangential section of the heat conduction coefficient from Lushan and Xinjin were larger than the P. zhennan ancient buried wood.They were in the order:cross section> tangential section> radial section.(6) P. zhennan wood from Lushan incompressive strength,bending strength and surface hardness were 34.8MPa,64.5 MPa,4495.3 N. P. zhennan wood from Xinjin incompressive strength,bending strength and surface hardness were36.2 MPa,67 MPa,4580.4N.The P. zhennan ancient buried wood incompressive strength,bending strength and surface hardness were 31.4 MPa,62.6 MPa,3103.5 N.The mechanical properties of P. zhennan wood from Xinjin were the best. |
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