• 论文及研究报告 •

### 杉木林的密度管理与长期生产力研究

1. 中国林业科学研究院林业研究所,北京100091
• 收稿日期:2001-05-11 修回日期:1900-01-01 出版日期:2001-09-25 发布日期:2001-09-25

### A STUDY ON STAND DENSITY MANAGEMENT AND LONG-TERM PRODUCTIVE OF CHINESE FIR (CUNNINGHAMIA LANCEOLATA) PLANTATION

Sheng Weitong

1. Research Institute of Forestry, CAF Beijing 100091
• Received:2001-05-11 Revised:1900-01-01 Online:2001-09-25 Published:2001-09-25

1987～1999年,在江西省分宜县中国林科院亚热带林业实验中心,对9a生的杉木人工林,进行了不同保留密度的管理。设立6个固定样地,对林下植被变化作了13a的连续观测,土壤肥力变化作了9a变化测定,并对水土流失、枯落物量及其分解速率进行了8a的测定。结果表明,凡经间伐的林分,林下植被获得了良好发育,13a中林下植被种类达到了30～36种,盖度达到80%～90%,而生物量达到5t·hm-2 以上。未经间伐密度较大的林分林下植被发育较迟,比间伐林分推迟8～9a。适度间伐不会产生不利于地力维护的水土流失,合理的林分密度管理可提高微生物数量,达2.42倍。林分密度低而林下植被发育好的林分,枯落物分解速度快。杉木中龄林阶段,土壤有机质含量有所下降,特别是16～30cm的土壤,水解N和速效P含量下降,速效N下降最明显。林分密度大,生长量大的林分,速效N、P下降幅度也大。因此,通过间伐适当降低林分密度,对维护土壤肥力有较大作用,因而有利于林地保持长期生产力。

Abstract:

Since 1987 to 1999,a study on the density management of Chinese fir plantations of 9-year-old was made continuously in the Experimental Center for Subtropical Forestry under the Chinese Academy of Forestry (CAF) located in Fenyi County, Jiangxi Province. Based on the establishment of 5 fixed sample plots in the stands with different retained density after thinning, the undergrowth vegetation had been observed for 13 years, the soil fertility in the stands had been tested for 9 years, the soil erosion as well as the amount of litters and their decomposition rates had been monitored for 8 years in the stands. The results showed that in all thinned stands with different thinning intensity, the undergrowth vegetation had developed very well, with the number of undergrowth plant species being increased to 30～36 species, the coverage of undergrowth vegetation being increased to 80%～90% , and the biomass of undergrowth vegetation being increased to 5t·hm-2 in 13 years, while in the dense stand without thinning the undergrowth vegetation developed poorly and 8～9 years later to reaching the same level than that in the thinned stands. The reasonable stand density management could also increase the amount of micro organisms by 2.42 times in the soil, which resulted in faster decomposition of litters in the stands with lower density and well-developed undergrowth vegetation. Generally, when the Chinese fir plantation grows into the middle-aged,the content of organic mater starts decreasing more or less in the soil, particularly in the soil layer at depth of 16～30 cm underground , the content of available nitrogen and phosphorous decrease significantly. So, in the dense and fast growing stands, the higher the stand density is , the more the available nitrogen and phosphorous decrease significantly in the soil. Therefore, the reasonable decreasing of stand density by means of thinning can conserve the soil fertility, so that the long-term productivity of forest land can be maintained.