Effect of Initial Planting Density on Afforestation of Robinia pseudoacacia in the Project of Returning Farmland to Forest
This paper analyzes the effect of initial planting density on the afforestation of Robinia pseudoacacia in the project of returning farmland to forest,so as to provide a reference and guidance for the implementation of the project.A Robinia pseudoacacia base in Xinxian county was selected as the study area,and different initial plant-ing densities were set,which were 833 hm2,1111 hm2,1350 hm2 and 1667 hm2,respectively,to analyze the effects of different initial planting densities on the survival rate and growth of Robinia pseudoacacia.The survival rate and disease rate of Robinia pseudoacacia were affected by different initial plant density.The survival rate and dis-ease rate of D3 treatment were higher than other treatments,and lower than other treatments.The tree height,DBH and crown width of D3 treatment were higher than those of other treatments,showing a trend of D3＞D4＞D2＞D1.The number of species in shrub layer and shrub layer under the initial plant density of 1350 plants/hm2 was more than that in other initial plant density groups.The number of species in shrub layer and shrub layer un-der D3 treatment was 2.33 times,2.33 times and 1.75 times,and the number of species in herb layer under D4,D3 and D1 treatment was 2 times,1.67 times and 1.25 times,respectively.When the initial planting density is high,the proportion of small-diameter trees is larger,while when the initial planting density is low,the proportion of large-diameter trees is larger.Under the initial planting density of 1350 hm2 treated with D3,the distribution of tree di-ameter and rank was relatively balanced,and the total stand stock was relatively high.Under the conditions of this experiment,the initial plant density has different degrees of influence on the growth of Robinia pseudoacacia,and the small initial plant density has greater influence on the large-diameter trees.The initial plant density is set to 1350hm2,and the distribution of tree diameter and rank is more balanced.Therefore,the initial plant density should be rationally preset to ensure the appropriate tree diameter and rank,promote the healthy growth of Robin-ia pseudoacacia and increase the total stand stock.Of course,in the specific setting of initial plant density selec-tion,the climate and soil conditions of the study should be taken into account so as to ensure the afforestation effect of Robinia pseudoacacia,but also improve the overall benefit of the project.
initial plant densityRobinia pseudoacaciareturn farmland to forestgrowth conditionsoil index
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