高阿丁枫人工中龄林生长对坡向和密度的响应

Growth Responses of Middle-aged Altingia excelsa Plantation to Slope Direction and Density

  • 摘要: 为了解高阿丁枫人工林的生长过程,2021年对林龄21 a的高阿丁枫人工林进行每木检尺,以胸径作为标准木选择的依据,西南坡不同密度中各选择1株,南坡不同密度中各选择3株高阿丁枫标准木作为解析木,分析不同坡向和造林密度组合的林木生长差异。结果表明:林龄21 a时,不同坡向和造林密度组合的高阿丁枫林木的平均胸径、树高和材积分别为17.60~20.78 cm、25.73~28.51 m和0.3186~0.4293 m3,林木尚处于旺盛的生长阶段;处理组合间以上生长量均呈现极显著的差异。林龄1~9、1~10、8~16 a期间分别是胸径、树高和材积的速生期,其连年生长量最高分别达2.19 cm/a、2.74 m/a和4.3966 × 10−2 m3/a。坡向、密度及其交互作用显著或极显著地影响高阿丁枫林木的生长。高阿丁枫隶属热区长寿命大径材树种,速生期延续较长,其生长对立地和密度较为敏感。优质高效的高阿丁枫人工林培育应选择最适宜的立地和造林密度,并且适时开展密度的动态调控。综上所述,造林密度通过影响树高生长从而影响材积生长,南坡采用3 m × 2 m × 5 m非均匀密度造林的单株总材积最大。研究结果可应用于生产实践中高阿丁枫优质高效人工林培育的立地选择和密度控制。

     

    Abstract: In order to understand the growth process of Altingia excelsa plantation, individual log scaling of 21-year-old A. excelsa plantation were conducted in 2021. Using diameter as the criterion for selecting standard trees, 1 tree was selected from each planting density in the southwest slope, while 3 trees were selected from each planting density in the south slope. Standard trees were chosen as analytical trees to analyze the differences in forest growth among different slope aspects and planting densities. The results showed that mean diameters at the breast height(DBHs), tree heights(THs) and volume of TCs consisted with different slope directions and planting densities for the 21-year-old stand trees were 17.60–20.78 cm, 25.73–28.51 m and 0.3186–0.4293 m3, respectively, and the trees were still in vigorous growth stage; there were significant differences of all above parameters between the TCs. The fast-growing periods of the DBH, TH and volume were presented in the ages for 1–9, 1–10 and 8–16 years old with the maximum current growth of which 2.19 cm/year, 2.74 m/year and 4.3966 × 10−2 m3/year, respectively. Slope direction, density and their interaction significantly affected the growth of A. excelsa stand trees. A. excelsa belongs to tree species of the long-lived and large-diameter timber in the topical and south-subtropical area. Its fast-growing period lasts for a long time, and its growth is more sensitive to the site and density. It is should to select the most suitable site and planting density for establishing A. excelsa plantation with high-quality and high-efficiency, and dynamically regulate stand density on due time. Comprehensively, the initial planting density will ultimately affected the volume by affecting the growth of tree heights, and the south slope was selected to match 3 m × 2 m × 5 m uneven row spacing could achieved the maximum volume of individual tree, which suggested to be applied to site selection and density control of high-quality and efficient plantation establishment of A. excelsa in the production practice.

     

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