华北落叶松近熟林生长量对密度控制的响应

为了确定华北落叶松近熟林生长量对密度控制的响应,以河北省塞罕坝机械林场38a生的华北落叶松纯林为研究对象,通过不同间伐强度的试验,分析其树高、胸径及材积的生长量、总生长量和连年生长量对密度控制的响应,结果表明:间伐后的胸径、材积总生长量和连年生长量均大于对照;且以林分密度达到225株/hm2时,6a胸径和材积生长量最高,分别达到了3.89cm和0.154 60m3,连年生长量均高于同期其他间伐区的生长量;高度与密度关联性不强,但是密度达到300株/hm2时,显著促进了高生长。因此,对于塞罕坝机械林场来说,华北落叶松纯林在达到近熟龄时生长量依然对密度控制有一定的反应,且密度为225~300株/hm2时最适宜生长。

The response of growth rate to density control of near-mature forest of Larix principis-rupprechtii Mayr

In order to study the response of growth volume to density control of the near-mature Larix principis-rupprechtii forest,we took the 38-year-old Larix principis-rupprechtii forest in Saihanba Mechanized Forest Farm of Hebei province as materials.Five pieces of sample areas whose land conditions were relatively consistent were set up among the Larix principis-rupprechtii plantations.One of them was for CK (control),and the others were designed into 4 different density gradients.The response of tree height,DBH,total and annual growth volume to density control was then analyzed.The results showed that:after thinning,the DBH,total growth volume,and annul growth volume were all higher than that of the CK;when the stand density was 225 plants/hm2,the DBH and volume growth of 6-year-old trees were the highest,which reached to 3.89 cm and 0.154 60 m3,respectively,and the annual growth increment was higher than that in other thinning areas.The correlation between height and density was not strong,but in the study,the hight growth was significantly promoted in the area with density of 300 plants/hm2.Therefore,the growth still has a certain reaction to density control and the most appropriate density was among 225～300 plants/hm2 for near-mature Saihanba Mechanized Forest Farm.