杉木速生家系树高生长对初植密度的早期响应

Early response of tree height to initial planting density for fast-growing families of Cunninghamia lanceolata

为了筛选不同杉木速生家系适宜的初植密度,利用杉木第3代种子园中的5个速生优良家系,在5种初植密度下造林试验,分析了试验林3 a林龄时的树高生长和保存率差异。结果表明:3 a林龄时,树高异速生长性、累积生长量,保存率在两两家系间具有不同的差异关系。家系F1的树高异速生长性对初植密度具有敏感性,在2500株·hm^(-2)的初植密度下单株间分化较小,变异系数为31.51%,比变异系数最大的密度低9.02个百分点。除家系F2外的4个家系的树高累积生长量对初植密度具有不同程度的敏感性,但都在3500株·hm^(-2)的初植密度下具有最大树高生长优势。家系F2、F5的保存率对初植密度敏感,在3100株·hm^(-2)的初植密度下保存率可达93%以上。为每个家系筛选了适宜的初植密度,使这些家系造林3 a后的平均树高达到2.60 m,比杉木第3代种子园良种提高8.96%,单株间树高异速生长性降低10.93%,保存率提高5.54个百分点。

In order to screen the appropriate initial density for different fast-growing families of Cunninghamia lanceolata.Using five fast-growing families from 3rd generation seed orchard,afforestation experiments were conducted under five initial planting densities.The tree height growth and preservation rate at the age of 3 years were analyzed.The results showed that the allometric growth,cumulative growth of tree height and preservation rate had different differences between the two lines at the age of 3 years.The tree height allometric growth of family F1 was sensitive to the initial density.At the initial density of 2500 plants·hm^(-2),the differentiation among individuals was small,and the coefficient of variation was 31.51%,which was 9.02%lower than the density with the largest coefficient of variation.Except family F2,the cumulative growth of tree height of the last 4 families had different degrees of sensitivity to the initial density,but all had the maximum height growth advantage under the initial planting density of 3500 plants·hm^(-2).The preservation rate of family F2 and family F5 were sensitive to the initial density,and the preservation rate could reach more than 93%at the initial density of 3100 plants·hm^(-2).The appropriate initial planting density was selected for each family,so that the average tree height reached 2.60 m after three years of afforestation,which was 8.96%higher than that of 3rd generation seed orchard,the allometric growth of tree height among individuals was reduced by 10.93%,and the survival rate was increased by 5.54%.