塞罕坝林区低密度经营对华北落叶松林分生长的影响

为了给坝上塞罕坝林区低密度经营提供依据,以华北落叶松人工林为研究对象,对不同林分密度条件下(150株/hm~2、225株/hm~2、300株/hm~2和375株/hm~2)华北落叶松林分的生长情况进行分析,研究低密度经营对华北落叶松生长的影响,提出培育华北落叶松大径级用材林的技术体系。结果表明:林分密度对胸径、树高和单株材积总生长量、平均生长量、连年生长量都有一定程度的影响,影响程度按照胸径、单株材积、树高顺序递减;林分密度过大或过小均影响华北落叶松林分的生长,林分密度控制在225~300株/hm~2时,华北落叶松胸径、树高和单株材积总生长量、平均生长量、连年生长量最大。

The effects of low-density management on growth of Larix principis -rupprechtii plantations in Saihanba Mechanized Forest Farm

The effects of stand density on growth of Larix principis-rupprechtii plantations were analyzed with the data of 38-year-old stands with different remaining densities (150,225,300,and 375 trees /hm2 respectively) in Saihanba Mechanized Forest Farm.The results showed that stand density had significant influences on DBH,tree height,and total,mean,and annual growth increment of single tree volume.The influence degree followed the decreasing order of DBH,the single tree volume,and tree height.When the stand density was 225～300 trees/hm2,the DBH,tree height,and the total,mean and annual growth increment of single tree volume reached the highest.However,the growth of DBH,tree height,and the single tree volume were restrained under the conditions of stand densities larger than 300 or lower than 225 trees/hm2.