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林业科学 ›› 2015, Vol. 51 ›› Issue (4): 8-15.doi: 10.11707/j.1001-7488.20150402

• 论文与研究报告 • 上一篇    下一篇

间伐强度对柏木人工林生长及林下植物的影响

龚固堂1, 牛牧2, 慕长龙1, 陈俊华1, 黎燕琼1, 朱志芳1, 郑绍伟1   

  1. 1. 四川省林业科学研究院 成都 610081;
    2. 北京林业大学林学院 北京 100083
  • 收稿日期:2014-05-19 修回日期:2014-11-30 出版日期:2015-04-25 发布日期:2015-05-20
  • 通讯作者: 慕长龙
  • 基金资助:

    林业公益性行业科研专项"川中丘陵区人工柏木林健康经营技术研究"(20100400208)。

Impacts of Different Thinning Intensities on Growth of Cupressus funebris Plantation and Understory Plants

Gong Gutang1, Niu Mu2, Mu Changlong1, Chen Junhua1, Li Yanqiong1, Zhu Zhifang1, Zheng Shaowei1   

  1. 1. Sichuan Academy of Forestry Chengdu 610081;
    2. College of Forestry, Beijing Forestry University Beijing 100083
  • Received:2014-05-19 Revised:2014-11-30 Online:2015-04-25 Published:2015-05-20

摘要:

【目的】 针对川中丘陵区普遍存在的柏木人工林密度过大、木材生产力低、林下灌草盖度低和天然更新不良等问题,开展生态疏伐试验,探讨间伐强度对林分生长和林下植物的影响,为开展柏木生态经济型防护林的营林活动提供参考。【方法】 以25年生柏木人工林为研究对象,采用随机区组方法,设置4种间伐强度(20%~25%,15%~20%,10%~15%和对照)的处理,观察林分胸径、树高、蓄积量、生物多样性和天然更新幼苗数量,探讨间伐强度对其影响。【结果】 不同强度间伐5年后林分平均胸径和胸径连年生长量在各处理之间均存在显著差异,胸径生长量随间伐强度加大而增加; 平均树高以20%~25%间伐强度最大, 达10.7 m,但20%~25%间伐强度与15%~20%间伐强度和10%~15%间伐强度之间无显著差异,而树高连年生长量在不同处理之间差异显著; 20%~25%,15%~20%和10%~15%不同强度间伐5年后林分蓄积量分别为97.35,93.43和93.19 m3 ·hm-2,均比对照小,但蓄积连年生长量随间伐强度由高到低分别为6.11,4.58和3.66 m3 ·hm-2a-1,均高于对照; 20%~25%间伐强度林分的灌木和草本 Simpson 指数分别为0.769 5和0.444 6,Shannon-Wiener 指数分别为1.702 5和0.769 0,都比其他处理高; 不同间伐强度天然更新幼苗株数仅在苗高5~30 cm 等级存在显著差异,30~50 和 50~150 cm的幼苗在不同处理之间差异不明显; 评价结果表明,综合得分以20%~25%间伐强度最大,且随间伐强度降低而减小。【结论】 间伐后保留木的生长空间和营养空间得到有效改善,林分胸径和树高生长量随间伐强度增大而增加,但不同间伐强度蓄积量差异不显著;适度间伐可提高林下灌木和草本生物多样性指数; 林分更新幼苗数量也随着间伐强度的增大而增加;就本研究的4种间伐强度而言,中龄阶段柏木人工林的适宜间伐强度为20%~25%。

关键词: 间伐强度, 柏木人工林, 林分生长, 生物多样性, 天然更新

Abstract:

【Objective】 Aimed at the problems of high stand density, poor timber productivity, low coverage of understory vegetation and poor natural regeneration of Cupressus funebris plantation in hilly areas in central Sichuan, a thinning experiment was carried out to analyze the impacts of different thinning intensities on the stand growth and the understory plants and to provide guidance for managing eco-economic protection forests in the region. 【Method】 A 25 years old cypress plantation was used for the experiment, four thinning intensities (20%-25%, 15%-20%, 10%-15%, and control) were used with a randomized block experimental design. DBH, height, volume, biodiversity, and number of naturally regenerated seedlings were measured to determine their responses to different thinning intensities.【Result】The results indicated that the mean stand DBH and current annual increment (CAI) of DBH were significantly different among various thinning intensities, and a higher thinning intensity led to a higher DHB increment. The maximum mean height (10.7 m) occurred in stands with 20%-25% thinning intensities, but not significantly different from those of thinning intensity of 15%-20% and 10%-15%.However, significant differences were found in the height CAI among the four thinning intensities. Standing volume was 97.35, 93.43, and 93.19 m3 ·hm-2 respectively in stand with thinning intensity of 20%-25%, 15%-20%, and 10%-15%, and were lower than that of the control. But the volume CAI was 6.11, 4.58, and 3.66 m3 ·hm-2a-1 respectively and higher than that of the control. The Simpson index of shrubs and herbs for stand thinned at 20% -25% was 0.769 5 and 0.444 6, Shannon-Wiener index was 1.702 5 and 0.769 0 respectively, and the values of both indices were higher than that of the other thinning intensities. The number of naturally-regenerated seedlings was significantly different among different thinning intensities only for seedlings of 5-30 cm in height, but no significant differences for seedlings of 30-50 and 50-150 cm height classes. A comprehensive evaluation showed that the highest score was found for the thinning intensity of 20%-25%, and the total score decreased with the lowering of thinning intensity. 【Conclusion】The growing space and nutritional condition were effectively improved for the retained trees after thinning, stand DBH and height were increased with the increase of thinning intensity. However, the stand volume was not significantly different among the four thinning intensities. Besides, thinning at appropriate intensities can increase the biodiversity indices of shrubs and herbs, the quantity of naturally regenerated seedlings also increased with the increase of thinning intensity. 20%-25% was the better one among the 4 thinning intensities for silvicultural interventions for the middle aged cypress plantation in the region.

Key words: thinning intensity, Cupressus funebris plantation, stand growth, biodiversity, natural regeneration

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