Comparison on the Physical and Mechanical Properties Between Clone and Seedling from Cunninghamia lanceolata
In order to reveal the differences in the physical and mechanical properties of wood from Cunning-hamia lanceolata clones and seedling plantations,the main physical and mechanical properties of wood from 26-year-old C.lanceolata clones and seedling plantations at different circumferential orientations(north-south orient-ation)and different height positions were measured,and the wood strength and quality coefficients were investig-ated to comprehensively evaluate the material grades of wood from C.lanceolata clones and seedling plantations.The results showed that in addition to impact toughness,the density,shrinkage,difference shrinkage,swelling rate(all dry-air dry),hardness,flexural strength,flexural modulus of elasticity,compressive strength parallel to grain,and transverse compressive strength of C.lanceolata clones were higher than those of seedlings;the influ-ence of circumferential orientation on the physical and mechanical strength of C.lanceolata clones and seedlings was not significant;tree height had a significant impact on the air dry density and water absorption of C.lanceol-ata clones wood,the basic density,air dry density,water absorption,transverse compressive strength,and hard-ness of seedling wood,while it had a significant impact on the basic density,total dry density,and volume mois-ture expansion of clone wood,the total dry density,and volume moisture expansion of seedling wood,and had no significant impact on other physical and mechanical strength of the 2 types of wood;the air dried density,end hardness,transverse compressive strength,and longitudinal compressive strength of the 2 types of wood showed a trend of first decreasing and then increasing with the increase of tree height;in addition to the shrinkage,the phys-ical and mechanical properties of the 2 types of wood were in the low-grade of domestic wood;the comprehens-ive quality coefficient of the 2 types of C.lanceolata wood was relatively high,and they were both high-grade wood.
Cunninghamia lanceolatacloneseedlingtimberphysical and mechanical propertydifference
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