间伐补植阔叶树大苗对杉木人工林生长的影响

发布时间：2018-04-20 04:16

  本文选题：杉木人工林 + 间伐强度　； 参考：《中南林业科技大学》2017年硕士论文

【摘要】：目前,大面积杉木人工纯林普遍存在林分结构单一、地力衰退、生产力低下、生物多样性下降、病虫害加剧等一系列生态问题,严重制约了林地生态服务功能和可持续发展利用。因此,将现有的杉木纯林改造为异龄针阔混交林是解决这一问题的关键,而在纯林下补植阔叶树为修复杉木纯林生态服务功能提供了一条有效途径。本文以福寿林场杉木人工中龄林为研究对象,采取随机区组设计对杉木人工林进行间伐和补植阔叶树的经营方式,于2012年开展试验对试验区内的杉木人工林进行3种间伐强度(20%、33%和56%)改造,林下补植3种阔叶树大苗(深山含笑(Mchelia maudiaae)、马褂木(LChiodendron Chinense)和栾树(Koelreuteria paniculata)),以未间伐补植的纯林为对照组,对照组和每个处理组设置3次重复,每块固定样地面积为20m×30m,进行连续定位监测。通过分析间伐补植4a后杉木人工林林分的生长状况、林分结构以及干形质量三方面,得出间伐补植阔叶树大苗对杉木人工林生长的影响,为今后杉木人工林的抚育管理及多功能可持续经营提供参考依据。主要结论如下:1.间伐补植改造对林木生长因子影响的结论为:(1)间伐补植改造对杉木林木的生长有促进影响,均显著提高了杉木的平均胸径、树高、冠幅、单株材积,并且随着间伐强度的增强而增大,而每个处理组的杉木林分蓄积量却显著低于对照组。处理组C的杉木平均胸径、树高、冠幅、单株材积的生长效果最佳,在伐后第4a时,分别较间伐前增加了 63.43%、49.04%、102.24%、265.52%;而林分蓄积量较间伐前减少了 11.84%。(2)间伐强度对补植的深山含笑、栾树、马褂木生长没有影响,但相比之下3种补植阔叶树在处理组C中的胸径和树高均达到最大,且大小顺序为深山含笑栾树马褂木。2.间伐补植改造对林木干形影响的结论为:(1)间伐补植后1-4a之间,枝下高、高径比及胸高形数变化均随间伐强度的增强而逐渐降低,而冠长率及尖削度随着间伐强度的增强而增大;(2)在不同间伐补植的时期下,杉木枝下高、高径比和胸高形数的年均生长率变化随着间伐强度增强呈大致下降的趋势,而冠长率的年均生长率随着间伐强度增强而增大。3.间伐补植改造对林分结构影响的结论为:(1)间伐补植在一定程度上有利于培育大径阶的杉木。间伐补植后1-4a之间,间伐补植林分胸径有进阶生长,杉木胸径在小径阶的分布有不同程度的减少,在10-12 cm之间的径阶株数上下波动,差异不大;在大径阶时随间伐年限增长较快,径阶分布右移。(2)对照组杉木的最大相对直径Rmax=1.1时,杉木株数所占百分数达到最大;在处理组A、B的相对直径分别为1.4和1.5时,杉木株数所占百分数也都达到最大;对照组杉木的最大相对树高Rmax=1.3时,杉木株数所占百分数达到最大;处理组A和处理组B的杉木林分相对树高分别为1.5和1.6时,杉木株数所占的百分数为最大。
[Abstract]:At present, there are a series of ecological problems such as single stand structure, declining soil fertility, low productivity, decreasing biodiversity, increasing diseases and insect pests and so on in large area Chinese fir artificial pure forest. The ecological service function and sustainable development of forest land are seriously restricted. Therefore, the key to solve this problem is to transform the existing pure Chinese fir forest into mixed coniferous and broad-leaved forest of different ages, and to repair the ecological service function of pure Chinese fir forest by planting broad-leaved trees under pure forest. In this paper, the artificial middle age forest of Chinese fir in Fushou Forest Farm was used as the research object, and the management mode of thinning and replanting broadleaved trees of Chinese fir plantation was carried out by random block design. In 2012, three types of thinning intensity of Chinese fir plantations in the experimental area were reformed, including 33% and 56% of thinning intensity. Three species of broad-leaved tree seedlings (Mchelia maudiaaeae, LChiodendron Chinenseet) and Koelreuteria paniculata were replanted under the forest as control group. The control group and each treatment group were set up three times, each fixed sample area of 20 m 脳 30 m, for continuous location monitoring. By analyzing the growth status, stand structure and dry form quality of Chinese fir plantations after 4 years of thinning and supplementary planting, the effects of broadleaf plantlets planted by thinning on the growth of Chinese fir plantations were obtained. It provides reference for tending management and multi-function sustainable management of Chinese fir plantation in the future. The main conclusions are as follows: 1. The effect of thinning and replanting on the growth factors of Chinese fir trees was concluded as follows: (1) the effects of thinning and replanting on the growth of Chinese fir trees were improved, and the average DBH, height, crown width, volume of individual trees were significantly increased. With the increase of thinning intensity, the accumulation of Chinese fir in each treatment group was significantly lower than that in the control group. The average DBH, height, crown width and volume of individual tree in treatment group C were the best. At the 4th year after cutting, the average DBH, height, crown width and volume of individual tree in treatment group C were increased by 63.43 and 49.04 and 49.04%, respectively, compared with those before thinning, respectively, and the volume of stand volume was decreased by 11.84. 2) the intensity of thinning decreased 11.84. 2) the effect of thinning on the depth of the supplementary planting was higher than that before the thinning, and the effect of thinning on the growth of Cunninghamia lanceolata was higher than that before thinning. There was no effect on the growth of Luan tree and mandarin tree, but in contrast, the DBH and height of the three kinds of replanted broadleaved trees reached the maximum in treatment group C, and the order of size was. 2. The conclusion of the effect of thinning and replanting on tree stem shape was: (1) between 1 and 4 years after thinning, the changes of branch height, ratio of height to diameter and number of chest height decreased with the increase of thinning intensity. However, with the increase of thinning intensity, the average annual growth rate of the ratio of height to diameter and the number of breast height of Chinese fir increased with the increase of thinning intensity. The average annual growth rate of Chinese fir under branch height, height to diameter ratio and breast height number decreased with the increase of thinning intensity. The average annual growth rate of crown length increased with the increase of thinning intensity. The conclusion of the effect of thinning and replanting on the stand structure is: (1) to some extent, the thinning and replanting is beneficial to the cultivation of Chinese fir with large diameter order (Cunninghamia lanceolata). From 1 to 4 years after thinning, the DBH of the thinning and replanting stand had advanced growth, the distribution of DBH in the small diameter order of Chinese fir decreased to some extent, and the number of DBH in 10-12 cm fluctuated up and down, the difference was not significant. The maximum relative diameter of Chinese fir (Rmax=1.1) in the control group was higher than that in the treatment group, and the relative diameter of the treatment group was 1. 4 and 1. 5, respectively, and the relative diameter of the treatment group was 1. 4 and 1. 5, respectively, while the relative diameter of the treatment group was 1. 4 and 1. 5, respectively. The percentage of Chinese fir trees reached the maximum when the maximum relative height of Chinese fir was Rmax=1.3 in control group, and when the relative tree height of treatment group A and treatment B was 1.5 and 1.6, respectively, the percentage of Chinese fir trees reached the highest in the control group when the maximum relative tree height of Chinese fir was 1. 5 and 1. 6, respectively, and that of treatment group B was 1. 5 and 1.6, respectively. The percentage of the number of Chinese fir trees was the largest.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S791.27
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本文编号：1776203