摘要
杉木幼林系统是由 4个不同密度级处理系列小区组成 ,栽植密度分为 1 6 6 5、3330、4995和 6 6 6 0株 /hm2 (以下分别用A、B、C和D代替 )。这些小区土壤质地及地形别无二致 ,都是用 1年生实生苗 1 987年春天定植。 8年生时调查了这些幼林系统林木生长、冠层厚度、枝下高以及生态效益等。随着密度由A增加到D :平均胸径生长量从 8 1cm降到 6 6cm ;平均树高生长量由 5 9m降至 5 4m ;平均冠层厚度自 4 9m变薄到3 3m ;平均枝下高由 1 0m上升到 2 3m ;这些系统生产力从A到D分别为 :4 6、7 3、9 5和 1 0 3t/hm2 ·a。不同密度系统迳流系数、液体迳流与固体迳流等 ,在A密度区依次为 1 35 %、1 9 4mm/hm2 ·a和 334kg/hm2 ·a ;在B密度区分别是 0 5 2 %、8 1mm/ /hm2 ·a及 1 38kg/hm2 ·a ;在C密度区先后是 0 6 9%、8 9mm / /hm2 ·a与 1 96kg/hm2 ·a ;在D密度区顺序为 0 75 %、1 1 8mm/ /hm2 ·a和 2 84kg/hm2 ·a ,B与C密度区生态效益比较好。最后根据 5个项目中 1 5个类目值排序综合评价 ,得分结果从大到小的次序是 :C密度得 5 0分 ,B密度得43分 ,D密度得 36分 ,A密度得 2
Chinese fir [\%Cunninghamia lanceolata\%(Lamb.)Hook.]plantation systems were a series experiment plots consisted of four density treatments: 1665trees/hm\+2, 3330trees/hm\+2,4995trees/hm\+2 and 6660 trees/hm\+2 (four densities levels are taken place by A,B,C and D).\;There were not differences in the soil texture and topography of the experimental plots. 1-year-old Chinese fir seedlings were planted in spring of 1987. Tree growth, canopy thickness, tree height under first branch, and ecological benefit of different plantation systems were investigated at 8-year-old of Chinese fir trees. The average DBH increment decreased from 8.1?cm to 6.6?cm with the increase of plantation density from A to D, at the same time the average tree height increment decreased from 5\^9?m to 5\^4?m, the canopy thickness thined from 4.9?m to 3.3?m, the average tree height under first branch raised from 1.0?m to 2.3?m. The productivities of different density systems were 4.6, 7.3, 9.5, 10.3 t/hm\+2\5a from A to D respectively. The systimatic runoff coefficient, liguid runoff, and solid runoff in the A density region were 1.35%, 19.4 mm/hm\+2\5a, and 334?kg/hm\+2\5a respectively, and those in the B density region were 0.52%, 8.1?mm/hm\+2\5a, and 138?kg/hm\+2\5a respectively, in the C density region were 0\^69?%, 8\^9?mm/hm\+2\5a, 196?kg/hm\+2\5a respectively, and 0.75%, 11.8?mm/hm\+2\5a, 284?kg/hm\+2\5a in the D density region respectively. The ecological benefits of B and C density region were better than others. The comprehensive evaluation results based on 5 intems including 15 category values showed that in the score of C density was 50, the score of B density was 43. The score of A density was 36, that of A density was 21.
出处
《林业科学》
CAS
CSCD
北大核心
2000年第z01期28-35,共8页
Scientia Silvae Sinicae
关键词
密度级
生态效益
经济效益
生产力
杉木幼林系统
Density level, Ecologic benefit, Liquid runoff, Solid runoff, Economic benefit, Productivity
