尾巨桉二代萌芽林不同林分密度及立地条件的生长调查分析

Investigation and Analysis on the Growth of Different Stand Densities and Site Condition in the Second Generation Sprouting Forest of E.urophylla×E.grandis

为探索不同培育目标的尾巨桉二代萌芽更新的优化林分密度和立地控制,对不同立地、保留不同林分密度的尾巨桉二代萌芽更新林的生长情况进行调查分析,结果表明:尾巨桉二代萌芽更新林生长受林分密度影响较大,以中小径材培育目标,适宜的林分密度宜控制在2050株/hm^(2),其长势较好、产量高,4年生林分平均树高、胸径、材积分别达15.64 m、13.25 cm和0.1047 m^(3),立木蓄积达到183.98 m^(3)/hm^(2);而密度为1350株/hm^(2)的林分生长好、后劲足、优势木比例多,适合作为中大径材为培育目标的林分密度控制;立地质量对萌芽林的生长也有较大影响,Ⅱ类地的萌芽林生长量显著或极显著高于Ⅲ类地,要确保尾巨桉二代更新林有较高的产量,应尽可能选择Ⅱ类地的进行二代萌芽更新,立地较差的实施二代萌芽更新,其生长潜力有限。

In order to explore the optimal stand density and site control of E.urophylla×E.grandis second generation sprout regeneration forest with different cultivation objectives,the growth of E.urophylla×E.grandis second generation sprout regeneration forest with different stand density was investigated and analyzed.The results showed that the growth of E.urophylla×E.grandis second generation sprout regeneration forest was greatly affected by the stand density.For the cultivation goal of small and medium-sized diameter timber,the appropriate stand density should be controlled at 2050 plants.hm^(2) with good growth and high yield.The tree height,chest diameter,and the timber points reached 15.64 m,13.25 cm,and 0.1047 m^(3),and the standing timber volume reached 183.98 m3.hm^(2);The forest with a density of 1350 plants.hm^(2) has good growth,sufficient stamina,and a large proportion of dominant trees,making it suitable for density control as a cultivation target for medium to large diameter timber;The quality of the site also has a significant impact on the growth of the sprout forest.The growth of the sprout forest in Class Ⅱ land is significantly or extremely significantly higher than that in Class Ⅲ land.To ensure a high yield of the second generation regeneration forest of E.urophylla×E.grandis,Class Ⅱ land should be selected as much as possible for second generation sprout regeneration.For poor site,the implementation of second-generation sprout regeneration has limited growth potential.