摘要
在杉木人工林抚育间伐强度试验20年中,研究不同间伐强度林分自然稀疏的变化,揭示自然稀疏株数与林分密度和立地条件的关系,对杉木林密度管理图自然稀疏线数学方程M=k1·k2作出检验,提出不同间伐强度林分直径、树高和林冠结构等。自然稀疏研究表明,CK和弱度间伐自然稀疏起始期高峰期早,稀疏量大,稀疏过程具连续性,按其稀疏量可分为轻微稀疏期、剧烈稀疏期和延续稀疏期等3个阶段,若不加以人为干预,自然稀疏将是一个漫长的过程。中度和强度间伐稀疏起始期和高峰期之间呈间歇性、稀疏阶段性不明显。研究发现,林分密度和立地条件对枯死木株数均有重要作用,但密度比立地条件更重要。杉木林密管图自然稀疏线数学方程经检验,相对误差3·91%,精度较高;对其用于不同间伐强度和不同地位指数林分的实用性检验结果,CK相对误差5·23%,其他检验项目相对误差均<5%,为容许试验误差,实用性较强。研究揭示了不同间伐强度林分径级和树高级分布规律等。研究还得出不同间伐强度林分枝下高、林冠长度和林冠相对高度的生长差异、变化动态及其与林龄增长的各种相关规律,并分别提出其与林龄和单株材积定期生长量相关的数学模型。
In the intermediate cutting intensity experiment of the Cunninghamia lanceolata Plantation for 20 years, the change pattern of stand natural thinning through the different intermediate cutting intensities was studied, the relationship between tree number of the natural thinning and the stand intensity ＆ site conditions was revealed, the mathematical equation M = k1·k2 of natural thinning lines of C. lanceolata stand density management map was tested, and the diameter, height and canopy structure laws of the stand with different intermediate cutting intensities were put forward. The natural thinning studies indicated that the starting period and peak period of the natural thinning through the CK and slight intermediate cutting were both early, the thinning amount was large and the thinning course possessed continuity. The three stages of the slight thinning period, intensive thinning period and continual thinning period could be divided out according to the thinning amount. The natural thinning would be a very long process without the artificial interference. The thinning starting period and peak period through the middle and strong intermediate felling are both late and assume intermittence. Their thinning stages were not evident. By means of the studies we also found that the stand density and site conditions had important effects on the dead and dying tree number, but the density was more important than the site conditions. Through the test, the relative error of the mathematical equation of natural thinning lines of C. lanceolata stand density management map was 3.91% and the precision was relatively high. The practical test results of the stand with different intermediate cutting intensities and different site indexes showed that the CK relative error was 5.23 %, the relative errors of the other tested items were all 〈 5 %, which were all the allowable experimental errors. The mathematical equation was comparatively practical. The studies revealed the distribution laws of diameter classes and height clas
出处
《林业科学》
EI
CAS
CSCD
北大核心
2006年第1期55-62,共8页
Scientia Silvae Sinicae
基金
江西省科委1976年重点项目部分研究内容
关键词
杉木林
间伐强度
自然稀疏
林分结构
Cunninghamia lanceolata
intermediate cutting intensity
natural thinning
stand structure
