江西分宜地区杉木人工林不同代数间生产力与生物量构成的比较研究

将选自江西分宜大岗山地区相同立地条件和发育阶段的1、2代林样地的林龄变为与1代林主样地的林龄一致，利用“杉木人工林生长与收获模型系统”中的部分模型，计算林龄变换后样地的平均优势高，以便实现1、2代林之间以优势高表示的生产力在同林龄，同立地的比较，用假设检验比较1、2代林生产力的差异，而后根据实测生物量计算的数据，用假设检验比较1、2代林树干、树根及枝叶在生物量中占百分比的差异。结果表明：在各种地立条件下，幼龄林1、2代林的生产力无显著差异；中龄林1代林的生产力要普遍高于2代林，立地条件越差差异越明显；4－12年生林分，1代林树干占生物量百分比要普遍高于2代林，1代林树根占生物量百分比要普遍低2代林，立地条件越差上述差异越明显；1代林与2代林枝、叶占生物量百分比无显著差异。

Comparison and Study on the Productivity and Biomass Component Proportions of Different Rotation of Chinese Fir Plantations in Fenyi, Jiangxi Province

The productivity of first rotation of Chinese fir (Cunninghamia lanceolata) was compared with that of the second rotation. The tree height of dominant tree was used as the indicator, which was not influenced by the stand density but influenced by the site condition and age of the stand. The stand age on the first and the second generations sample plots of Chinese fir with similar site condition and development stage in Dagangshan of Jiangxi Province was in keeping with that of the main plot of first rotation, and height of dominant trees was calculated after the age-changing by using Growth and Yield Model System of Chinese Fir Plantation, so as to compare the dominant heights between the first and second rotation stands with similar stand age and site conditions. Based on the data of practical measuring of biomass, the differences of biomass percentage of trunk, root and leaves were compared by the method of hypothesis testing. The results showed that there was no significant difference of productivity between the first and the second rotation young stands under various site conditions. The productivity of first rotation middle-aged stand was higher than that of the second rotation stand. The poorer the site condition, the more significant the difference. For 4～12 years old stands, it was showed that: (1) The percentage of trunk in the total biomass was higher for first rotation stand than for the second rotation stand. (2) The percentage of root in the total biomass was lower for first rotation stand than for the second rotation stand. The poorer the site condition, the more significant the difference. (3) There existed no significant difference of percentage of leaves and branches in total biomass between first and second rotation stands.