南方型杨树工业原料林培育目标与培育年限的定量化研究

根据湖北省10个县、市31块标准地林分的调查资料,在对杨树所处立地条件和林分密度类型进行分级组合的基础上,对南方型杨树工业原料林的培育目标与培育年限进行了定量化研究。研究结果表明:各组合类型培育小径材、中径材、大径材的平均年限分别为6,7～9a,10～11a以上;各种立地条件下,中密度林分培育各种规格的工业原料林的年限最短;Ⅰ类立地中密度类型培育不同用途林分的年限最短,Ⅲ类立地低密度类型最长;Ⅰ类立地中密度和低密度组合类型较好,培育大、中、小径材均较理想,Ⅱ类立地中密度类型林分不宜培育大径材,Ⅲ类立地各种密度类型差别不大,以中密度林分最好。

Quantitative Studies on Different Cultivation Objectives and Age Limits of Industrial Material Forest from Southern Type of Poplar

Based on classification and combining site conditions and forest densities for southern type of poplar, the cultivation objective and age limit of industrial matcria forests were studied quantitatively in accordance with investigation data at 10 counties and cities of Hubei province of forest stand in 31 standard plot. The main conclusions arc as follows: The average age limits for cultivation on small—diameter, middle—diameter and large—diameter timbers arc 6, 7～9 a and more than 10～11 a respectively for all combination types. The age limit is the shortest for all specification of industriy to cultivate material forest cultivated from middle density stand. The age limit is the shortest for different purposes of stand cultivated from middle—density category at type Ⅰ site, but the longest from low—density category at Type Ⅲ site. At type Ⅰ site, it is better combination selection to more ideally cultivate large, middle and small—diameter timbers when using categories of middle—density and low density; however, at type Ⅱ site, the middle—density forest stand is not suitable for cultivation of large—diameter timber and at type Ⅲ site, there arc not very large difference among various categories of density among which the middle—density forest is the best.