基于无节柱材培育的修枝对杉木木材材性的影响OA

[Objective]This research aims to compare the effects of pruning and non-pruning on the physical and mechanical properties of Chinese fir(Cunninghamia lanceolata)wood and to provide a scientific basis for the cultivation of large-diameter,knot-free timber.[Method]A 17-year-old Chinese fir plantation was selected as the study site.A randomized block design was implemented with two treatments:pruning and non-pruning.Twenty years after pruning,the mean sample tree method was employed to select representative pruned and non-pruned trees for the measurement of various physical and mechanical properties of the wood.[Result]After 20 years of pruning in a 17-year-old mid-rotation stand,the form factor of Chinese fir wood was significantly increased.Pruning had no significant effect on stem taper,height-to-diameter ratio,oven-dry density,air-dry density,volumetric shrinkage coefficient,shrinkage rate,or swelling rate.However,pruning significantly reduced tangential hardness,radial hardness,compressive strength,and tensile strength.Specifically,the tangential and radial hardness of pruned wood were 14.52%and 16.43%lower,respectively,than those of non-pruned wood.The order of hardness across grain directions was:endwise＞tangential＞radial.No significant differences were observed in endwise hardness or modulus of elasticity between pruned and non-pruned wood.[Conclusion]After 20 years,pruning significantly influenced the form factor and certain mechanical properties of Chinese fir wood but did not significantly affect stem taper or height-to-diameter ratio.While tangential and radial hardness,compressive strength,and tensile strength were significantly reduced,endwise hardness and modulus of elasticity remained unaffected.Both pruned and non-pruned Chinese fir wood exhibited physical and mechanical properties within the"very low to low"range.The comprehensive strength quality coefficient of pruned wood was slightly lower than that of non-pruned wood;however,pruning did not alter its overall classification.Both types of wood were classified as low-strength timber.