花岗岩条件下杉木人工林的多代效应研究

在全国杉木中心产区的闽北林区 ,选择花岗岩母质发育的不同栽植代数 ( 1、2、3代 )、不同立地 ( 1 4、1 6、1 8地位指数 )、不同发育阶段 (幼龄林、中龄林、成熟林 )的杉木人工林 ,进行不同栽植代数及不同发育阶段杉木人工林生长发育效应研究 ,结果表明 :不同发育阶段杉木人工林存在明显的多代效应 ,栽植代数对不同发育阶段杉木林生长具有明显影响 .在不同立地和不同发育阶段的杉木人工林中 ,杉木胸径、树高及蓄积量生长均随栽植代数的增加呈逐代下降趋势 ,表现为 1代 >2代 >3代 .在 1 6地位指数条件下 ,2、 3代各发育阶段杉木胸径分别比 1代杉木下降 9.72 %～ 1 7.62 %和 1 8.85 %～ 2 6.90 % ,树高下降 4.2 6%～ 1 2 .5 6%和 8.5 1 %～ 1 5 .96% ,3代杉木胸径及树高分别比 2代杉木下降 1 .49%～ 1 9.0 2 %和 3.88%～ 4.5 9% ;同时连栽杉木胸径及树高生长速生期推迟 ,速生期变短 ,连栽杉木林表现出明显衰退趋势

Rotation Effect on Chinese fir Plantations in Granite Lands

Rotation effect on Chinese fir plantations was studied through the investigation of different generation, age and site plantations in granite lands in north Fujian Province The growths of Chinese fir in different age plantations were influenced significantly by the planting generation As planting generation increased,the growth of D B H,height and volume in different age plantations decreased,their growth were in the sequence of the first generation plantations>the second generation plantations>the third generation plantations Compared to the first generation plantations under 16 index site,D B H of the second generation and the third generation plantations decreased by 9 72%～17 62% and 18 85%～26 9% respectively,while height of the second generation and the third generation plantations decreased by 4 26%～12 56% and 8 51%～15 96% respectively D B H and height of the third generation plantations decreased by 1 49%～19 02% and 3 88%～4 59 respectively compared with the second generation plantations Moreover,the fast grow period of D B H and height became short after successive planting Successive planting of Chinese fir showed significantly decline tendency