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    张晓红, 张会儒. 蒙古栎次生林垂直结构特征对目标树经营的响应[J]. 北京林业大学学报, 2019, 41(5): 56-65. DOI: 10.13332/j.1000-1522.20190046
    引用本文: 张晓红, 张会儒. 蒙古栎次生林垂直结构特征对目标树经营的响应[J]. 北京林业大学学报, 2019, 41(5): 56-65. DOI: 10.13332/j.1000-1522.20190046
    Zhang Xiaohong, Zhang Huiru. Response of vertical structure characteristics of natural secondary Quercus mongolica forest to crop tree release[J]. Journal of Beijing Forestry University, 2019, 41(5): 56-65. DOI: 10.13332/j.1000-1522.20190046
    Citation: Zhang Xiaohong, Zhang Huiru. Response of vertical structure characteristics of natural secondary Quercus mongolica forest to crop tree release[J]. Journal of Beijing Forestry University, 2019, 41(5): 56-65. DOI: 10.13332/j.1000-1522.20190046

    蒙古栎次生林垂直结构特征对目标树经营的响应

    Response of vertical structure characteristics of natural secondary Quercus mongolica forest to crop tree release

    • 摘要:
      目的基于单株木的目标树经营技术是实现近自然森林经营的重要途径。为揭示目标树经营对天然次生林垂直结构的影响,以长白山北部蒙古栎次生林为研究对象,探讨各林层林分结构与单木生长对不同目标树抚育间伐强度的响应,为制定科学合理的经营措施提供基础依据。
      方法2013年8月在吉林省汪清林业局设置16块面积0.09 hm2(30 m × 30 m)的样地开展目标树经营试验。根据间伐强度设置弱度(5%)、轻度(10%)、中度(20%)和对照4种处理,每种处理4个重复,2016年复测样地。采用树冠光竞争高法(CCH)将林分划分为上林层、中林层和下林层3个林层,比较分析不同抚育间伐强度对各林层高度、树种组成、林木竞争和生长的影响。
      结果(1)各林层树冠光竞争高度分别为上林层15.27 ~ 16.12 m、中林层8.76 ~ 9.65 m、下林层2.95 ~ 3.37 m。间伐提高了上、中林层高度,其中中度间伐下上林层平均高度为15.42 ~ 17.21 m,显著高于其他处理,而下林层高度基本不变。(2)间伐调整了上林层和中林层各树种所占比重,上林层中白桦下降,蒙古栎提高,且蒙古栎比重随着间伐强度的增大而增大;中林层白桦、杂木比重下降,红松比重增加。(3)上林层平均胸径在中度间伐下得到了提高,增幅达到0.57 cm,而在其他处理下有所下降。中林层平均胸径只在轻度间伐下得到提升,下林层平均胸径的变化与上林层呈现相反的趋势。林分中上林层所占蓄积比重增大,弱度、轻度、中度间伐样地上林层蓄积比重分别增加了1.92%、11.52%、13.15%。(4)间伐显著降低了各林层林木竞争指数,其中下林层对目标树抚育间伐响应最为积极,以弱度间伐的降幅最为显著,林木竞争指数由0.634降为0.455。(5)各林层直径定期生长率和材积定期生长率随林层高度的增加而降低,上、中、下林层的直径生长率分别为1.22% ~ 1.96%、1.94% ~ 2.59%、4.02% ~ 8.17%,材积生长率分别为1.74% ~ 4.10%、3.50% ~ 5.14%、10.12% ~ 18.97%。
      结论目标树经营能够显著影响蒙古栎次生林各林层的生长与结构,但是各林层特征对不同抚育间伐强度的响应不一致。综合来看,中度间伐(间伐强度20%左右)是研究区蒙古栎次生林较为适合的目标树抚育间伐强度,有关具体抚育方式和后续抚育时间还有待林分动态的长期观测。

       

      Abstract:
      ObjectiveCrop tree release (CTR) based on single tree is an important way to realize close-to-nature forest management. In order to reveal influences of CTR on the vertical structure of natural secondary forests, natural secondary Quercus mongolica forest in the northern Changbai Mountains was used as research objects, to investigate the response of forest stand structure and single-wood growth to the different intensity tending, which can provide basic support for developing scientific and rational management.
      Method16 sample plots of 0.09 ha (30 m×30 m) were set up in the Jilin Wangqing Forestry Bureau in August 2013, to carry out crop tree release and thinning test. According to the thinning intensity, 4 treatments were set as: weak (5%), mild (10%), moderate (20%) and control, each treatment had 4 replicates. All sample plots were resurveyed in 2016. The stands were divided into upper, middle and lower storeys according to the canopy competition height (CCH) in stand. The effects of different tending thinning intensity on each forest storey height, tree species composition, competition and growth were analyzed.
      Result(1) the CCH of upper, middle and lower storeys was 15.27−16.12 m, 8.76−9.65 m and 2.95−3.37 m, respectively. Thinning increased the height of upper and middle forest storeys, upper forest storey height was increased from 15.42 to 17.21 by moderate thinning, which was significantly higher than other treatments, while the height of the lower forest storey remained basically unchanged. (2) Thinning adjusted the proportion of tree species in the upper and middle forest storeys. the proportion of Betula platyphylla was decreased while that of Quercus mongolica was increased in upper forest storeys, and the proportion of Quercus mongolica increased with the increase of thinning intensity. The proportion of other wood decreased while that of Pinus koraiensis increased. (3) The average DBH of upper storeys was improved under moderate thinning, with an increase of 0.57 cm, but decreased under other treatments. The average DBH of middle storey was only improved under mild thinning. Changes on average DBH of lower storey was opposite to that of upper forest storey. The proportion of upper and middle forest storeys of forest stands increased. The proportion of forest storeys in the weak, mild and moderate thinned sample plot increased by 1.92%, 11.52% and 13.15%, respectively. (4) Thinning significantly reduced the competition index of forest trees in each forest storey. The lower forest storey had the most positive response to crop tree tending and thinning. The forest competition index of lower storeys by weak thinning decreased from 0.634 to 0.455, which was the most significant. (5) DBH periodic growth rate and volume periodic growth rate of forest storey decreased with the increase of the height of forest storey. The DBH periodic growth rates of the upper, middle and lower forest storey were 1.22%−1.96%, 1.94%−2.59%, 4.02%−8.17%, respectively. The volume growth rate were 1.74%−4.10%, 3.50%−5.14%, 10.12%−18.97%, respectively.
      ConclusionCTR can significantly affect the growth and structure of different forest storeys of secondary Quercus mongolica forest. On the whole, moderate thinning (about 20% of thinning intensity) is suitable crop tree thinning intensity for secondary Quercus mongolica forest in study area. The specific tending methods and follow-up time are still based on long-term observations of forest stand dynamics.

       

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