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中国农学通报

中国农学通报 ›› 2023, Vol. 39 ›› Issue (20): 14-21.doi: 10.11924/j.issn.1000-6850.casb2022-0565

• 林学·园艺·园林 • 上一篇    下一篇

间伐对樟树人工林径级结构变化及生长影响

廖德志1(), 陈明皋1, 吴际友1(), 程勇1, 张珉1, 魏志恒1, 刘欲晓2, 单志毅3, 吴哲4   

  1. 1 湖南省林业科学院，长沙 410004
    2 攸县林业局，湖南攸县 412300
    3 攸县黄丰桥国有林场，湖南攸县 412307
    4 湖南汇智农林工程咨询设计有限公司，长沙 410004
  • 收稿日期:2022-07-07 修回日期:2022-09-22 出版日期:2023-07-15 发布日期:2023-07-10
  • 通讯作者: 吴际友，男，1963年出生，湖南常德人，研究员，博士，研究方向：森林培育。通信地址：410004 长沙市天心区韶山南路658号，E-mail：805610788@qq.com。
  • 作者简介:

    廖德志，男，1979年出生，湖南长沙人，研究员，硕士，研究方向：森林培育。通信地址：410004 长沙市天心区韶山南路658号，E-mail：。

  • 基金资助:
    国家“十三五”重点研发计划“樟树等高效培育技术研究”(2016YFD0600605)

Effect of Thinning Intensity on the DBH Structure and Growth of Cinnamomum carnphora Plantations

LIAO Dezhi1(), CHEN Minggao1, WU Jiyou1(), CHENG Yong1, ZHANG Min1, WEI Zhiheng1, LIU Yuxiao2, SHAN Zhiyi3, WU Zhe4   

  1. 1 Hunan Academy of Forestry, Changsha 410004
    2 Forestry Bureau of Youxian County, Youxian, Hunan 412300
    3 Hangfengqiao State-owned Forest Farm, Youxian, Hunan 412307
    4 Hunan Huizhi Agricultural and Forestry Engineering Consulting Design Co., Ltd., Changsha 410004
  • Received:2022-07-07 Revised:2022-09-22 Online:2023-07-15 Published:2023-07-10

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摘要：

樟树是中国南方重要的用材树种和绿化树种，目前营造的樟树人工林普遍存在林分生长参差不齐、生长较慢、出材率不高等问题。改善樟树人工林林分结构，提高林分生产力，培育樟树大径材已经成为目前樟树人工林培育和改造的主要任务。以16年生的樟树人工林为研究对象，建立9个20 m×30 m的固定样地，按照样地内立木总株数开展强度间伐（间伐40%）、轻度间伐（间伐20%）和对照组（不间伐）3组间伐试验，伐取解析木分析樟树人工林生长过程，探讨间伐前后樟树林分径级结构的动态变化情况。结果表明：（1）轻度间伐与强度间伐的试验样地，间伐生长2年后年，平均单株胸径年增长量分别为1.18 cm、1.42 cm，显著高于对照组和间伐前；间伐后各试验样地树高生长差异不显著，年增量均为0.5 m左右，但冠幅生长则显示出显著差异，强度间伐样地的单株平均冠幅达3.8 m，高出对照组31%。（2）分析3组样地的林分径级结构发现，样地内的被压木生长势明显不足，大约有25%的下层林分（胸径小于 12 cm）胸径基本没有增长；而强度间伐样地胸径20 cm以上的林木数量大幅度增加，达到了420株/hm2，样地内占比47.7%，轻度间伐则为285株/hm2，占比26.3%，而对照组仅为165株/hm2，占比11.9%。（3）比较分析了3组样地的林分蓄积量的变化动态，结果表明轻度间伐和强度间伐的样地内蓄积年生长量达到了21.91 m3/hm2和25.50 m3/hm2，显著高于不间伐样地的18.34 m3/hm2。通过实施40%的强度间伐实现了樟树中龄林林分整体增长，林分胸径、材积的增长速率相比于不间伐林分显著提高；同时分析数据发现不间伐林分中的被压木生长势不足，不仅自身生长停滞更会影响整个林分的生长；间伐在一定程度上减少了林木间的竞争，增加林内光照，改善了林分卫生条件，为保留木创造了更多的养分和生长空间，从而促进了林分的生长。但间伐所带生长势恢复时效以及间伐频率有待进一步观测。

关键词: 樟树人工林, 间伐, 生长规律, 森林培育

Abstract:

Cinnamomum carnphora is an important timber tree and greening tree species in South China. At present, Cinnamomum carnphora plantations generally have problems such as uneven and slow growth, and low timber outturn rate. Improving the forest stand structure of camphor plantations and the forest stand productivity, and cultivating large-diameter timber have become the main tasks of camphor plantation cultivation and transformation. Nine fixed observation plots with 16-year-old Cinnamomum carnphora artificial forest were established, each had the size of 20m×30m. According to the total number of standing trees in the plots, three groups of thinning experiments were carried out: intensive thinning (thinning 40%), light thinning (thinning 20%) and control group (no thinning). At the same time, analytic trees were harvested to analyze the growth process of camphor plantation. The dynamic changes of the diameter structure of camphor forest stand before and after thinning were discussed. (1) For the plots with light thinning and intensive thinning, after two years of thinning, the annual growth of DBH (breast-height diameter) of single plant was 1.18cm and 1.42cm, significantly higher than that of the control group and before thinning; there was no significant difference in the tree height growth after thinning, and the annual increment was about 0.5m; and the crown width growth showed significant differences, the average crown width of the intensity thinning plots was 3.8m, 31% higher than that of the control group. (2) By analyzing the stand DBH structure of the three groups of plots, it was found that the growth potential of the pressed trees in the plots was obviously insufficient, and about 25% of the lower stands (DBH less than 12cm) had no increase in DBH; however, the number of trees with DBH above 20 cm increased significantly in intensive thinning plots, reaching 420 trees/ hm2 and accounting for 47.7% in each plot, while the number in light thinning and control group was 285 and 165 trees/ hm2, respectively, accounting for 26.3% and 11.9% in each plot. (3) The changes of stand volume in the three groups of plots were compared and analyzed, and the results showed that the annual growth of stand volume in the plots with light thinning and intensive thinning reached 21.91m3/hm2 and 25.50m3/hm2, respectively, which was significantly higher than that in the plot without thinning (18.34m3/hm2). The overall growth of mid-aged camphor forest stands can be achieved by 40% intensive thinning，and the growth rate of DBH and stand volume are significantly higher than those of the no thinning stand. The growth potential of pressed wood in the no thinning stand is insufficient, which will not only stop its own growth but also affect the growth of the whole stand. Thinning reduces the competition among trees to a certain extent, increases the illumination in the forest, improves the sanitary conditions of the forest, provide more nutrients and growth space for the reserved trees, thus promoting the growth of the forest stand. However, the recovery time of the growth potential and thinning frequency need to be further studied.

Key words: Cinnamomum carnphora plantation, thinning, growth regularity, forest cultivation