| Pinus massoniana as a more common timber forest tree species in Hunan Province,for the construction,furniture manufacturing,paint industry and the use of wood fiber industry.In recent years,China’s growing demand for the timber market,plantation developed rapidly.Tending thinning as a measure of people to take the initiative to transform the stand,in the forest density or reach a high canopy density,the corresponding forest management measures to promote the retention of wood growth,the cultivation of large diameter wood has a significance.In this paper,the effects of tending thinning on the growth of Pinus massoniana plantation and the effect on forest fertility were studied by tending thinning of Pinus massoniana plantation in Huangcao Town,Zixing City,Hunan Province.Which for the future to better grasp the growth trend of stand,give full play to the economic and ecological benefits of plantation is of great significance.Based on the comparative analysis of the Pinus massoniana thinning plots and control plot of 18a Pinus massoniana,The growth rules of DBH,tree height,volume of Pinus massoniana,the biomass of standings and standings of Pinus massoniana,stand productivity,forest fertility and soil properties were studied.The results are as follows:(1)The diapause structure of the 18-year-old Pinus massoniana thinning plots and the control plot showed a normal distribution,and the DBH of the Pinus massoniana thinning plot was mainly distributed in the 16-diameter stage,while the control Pinus massoniana forest Mainly distributed in the 14-channel order.The number of large-diameter wood(22cm-26cm)was significantly higher than that of the control plot.(2)At the DBH growth,The thinning average standard wood and control average standard wood DBH were 15.4 cm and 13.4 cm.The annual growth and average growth of the thinning average standard wood reached the maximum at 15a and 18a.The annual growth and average growth of the control average standard wood reached the maximum at 9a and 12a.(3)In the aspect of tree height growth,the tree height of thinning average standard wood and control average standard wood were 14.4m and 13.8m respectively in tree height growth.The average growth rate of thinning average standard wood and control average standard wood was the same highest at 9a,and the average growth rate reached the maximum at 9a～12a.The annual growth of the successive years and the average growth rate of the intersection and the tending of the thinning standard wood than the control sample standard wood to appear later.(4)In terms of volume growth,the thinning average standard wood and the control average standard wood weight of the 18a litter were 0.1444m3 and 0.1037m3,respectively.The average growth of the average standard wood and control average standard wood were the highest at 18a,while the annual growth and average growth of volume growth had not yet reached the intersection.(5)The annual average growth rates of the DBH of Pinus massoniana thinning plot and control plot were 0.98cm and 0.62cm.The average annual growth of tree height was 0.72m,0.64m.The average annual growth of Pinus massoniana and Pinus massoniana per plant volume was 0.0196 m3 and 0.0110 m3.(6)The standard thinning wood and the standard control wood biomass of Pinus massoniana were 86.03 kg and 65.60 kg,The biomass of each plant was as follows:trunk>tree root>tree branch>leaf>bark,tree trunk>tree root>tree branch>bark>leaves.The forest biomass of the plot and the control plot were 178.08t ·hm2 and 164.33t-hm2.The annual net growth was 9.79t ·hm2·a-1and 8.99t ·hm2·a-1.(7)In BNR,the thinning plot was less than the control plot,which was 1.78 and 1.95.In the leaf index(BNI),the thinning plot was slightly larger than that of the control plot.The ratio of photosynthetic organs to non-photosynthetic organs(FC)was 0.07 and 0.06,and the thinning plot was larger than the control plot.The ratio of biomass to ground biomass(STR)was not significantly different from that of aboveground biomass,which was 0.55 and 0.54.The difference between the crown and root(CRR)values was 5.24 and 4.43.(8)The soil water content of the thinning plot and control plot was 29.87%,25.08%.and the soil water holding capacity was 53.27%and 37.63%,respectively.The thinning plot to be much higher.On the other hand,the two standard saturated water holding capacity were 57.28%,40.92%.Soil bulk density were 1.12,1.38,The stand after tending thinning reflects the soil structure is more mature and stable. |
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