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林业科学 ›› 2021, Vol. 57 ›› Issue (7): 1-10.doi: 10.11707/j.1001-7488.20210701

• 论文与研究报告 • 上一篇    下一篇

桥山林区3种麻栎群落类型的种群动态与幼苗特征

张维伟,赵忠*,刘金良,邓平   

  1. 西北农林科技大学林学院 陕西省林业综合重点实验室 国家林业和草原局黄土高原林木培育重点开放实验室 杨凌 712100
  • 收稿日期:2019-11-25 出版日期:2021-07-25 发布日期:2021-09-02
  • 通讯作者: 赵忠
  • 基金资助:
    国家自然科学基金项目(2017YFC0504605)

Population Dynamics and Seedling Characteristics of Three Community Types of Quercus acutissima in Qiaoshan Forest Region

Weiwei Zhang,Zhong Zhao*,Jinliang Liu,Ping Deng   

  1. College of Forestry, Northwest Agriculture and Forestry University Key Comprehensive Laboratory of Forestry, Shaanxi Province Key Laboratory of Silviculture on the Loess Plateau, National Forestry and Grassland Administration Yangling 712100
  • Received:2019-11-25 Online:2021-07-25 Published:2021-09-02
  • Contact: Zhong Zhao

摘要:

目的: 对比分析黄土高原南部桥山林区3种林分类型麻栎群落的种群结构与幼苗生长过程,阐明麻栎种群在不同群落类型下的数量和结构动态,为该地区麻栎林科学经营和恢复提供依据。方法: 采用样地调查法,调查12块样地(麻栎阔叶混交林、麻栎油松混交林和麻栎纯林3种林分类型,每种林分类型设置4块样地)内所有胸径大于4 cm个体的胸径(幼苗地径)、树高和冠幅等特征;在每块样地采集幼苗或幼树标准株,测定各器官生物量。以径级结构和高度级结构代替年龄结构,编制不同林分类型麻栎种群静态生命表,根据各径级麻栎种群存活量绘制存活曲线,并分析3种林分类型中1~10年生麻栎实生幼苗的高度、基径、冠幅及生物量分配差异。结果: 3种林分类型麻栎种群均呈现出随年龄增加个体数减小趋势,低龄级个体具有绝对数量优势,桥山地区麻栎种群年龄结构呈进展型。种群静态生命表表明,麻栎种群存活量随年龄增加呈降低趋势,低龄级死亡最高,为生活史脆弱期;Ⅲ、Ⅳ龄级期望寿命最高;在Ⅲ~Ⅶ龄级,麻栎阔叶混交林和麻栎油松混交林中的麻栎种群死亡率远远低于麻栎纯林。不同林分类型麻栎种群的存活曲线皆呈Deevey-Ⅲ型。实生苗基径在1~5年表现为麻栎纯林>混交林,随着年龄增加,麻栎油松混交林实生苗基径略高于其他2种林分类型,但3种林分类型间差异不显著;实生苗冠幅在2~10年表现为混交林>纯林,且3种林分类型间实生苗冠幅差异在4年后开始显著(P<0.05);麻栎油松混交林实生苗高度在2~10年均高于其他2种林分类型,3种林分类型间实生苗高度差异在5年后开始显著(P<0.05)。不同林分类型麻栎实生苗叶、干、根、侧枝生物量均随年龄增加而增长。3种林分类型间,实生苗叶生物量在1~6年差异不显著,干生物量在1~4年无显著性差异,侧枝生物量在1~2年差异不显著;随着年龄增加,3种林分类型间叶、干和侧枝生物量差异越来越显著;根生物量则随年龄变化没有太大差异。结论: 桥山林区3种林分类型麻栎种群发育良好,均具有一定的更新能力。麻栎纯林中大径级麻栎个体数较麻栎油松混交林和麻栎阔叶混交林少,麻栎纯林虽然早期幼苗数量较多,但幼树期死亡率较高,且高年龄幼苗的生长特性和各构件生物量均低于混交林,未来可将发展群落结构更稳定的混交林作为森林培育和经营的主要方向。

关键词: 麻栎, 种群结构, 生境, 生长特性, 生物量

Abstract:

Objective: By comparing population structure and seedling growth of Quercus acutissima among three different community types, the purpose of the study was to illustrate the quantitative and structural dynamics of Q. acutissima populations, in order to provide a basis for forest restoration and management in Qiaoshan forest region, southern Loess Plateau, China. Method: Field survey was conducted in 12 fixed plots(3 different stand types×4 reduplicates). All Q. acutissima individuals(DBH>4 cm) were measured for DBH(ground diameter for seedlings), height and crown width. Biomass of different organs was also measured for typical seedlings sampled from each plot. By substituting diameter class for age class, the static life table and survival curve were draw according to the survival amount of Q. acutissima in each diameter class. Differences among growth characteristics(height, ground diameter, crown width, and biomass allocation) of 1-10 years seedlings in three community types were analyzed. Result: The number of individuals tended to decrease with age in all of the three stand types of Q. acutissima, i.e. the low age classes displayed an absolute advantage in number of trees, indicating that the Q. acutissima population is progressive in Qiaoshan region. The static life table of the Q. acutissima population showed that the highest mortality rate occurred at younger diameter class indicating the phase was the most vulnerable stage in life history of Q. acutissima. The life expectancy was the highest in age classes ofⅠand Ⅱ. The mortality of Q. acutissima between age classes of Ⅲ to Ⅳ is far lower in mixed forest of Q. acutissima with broad leaved tree and mixed forest of Q. acutissima with Pinus tabulaeformis than that in pure forest of Q.acutissima. The survival curve of the different Q. acutissima populations was Deevey-Ⅲ type. The ground diameter of seedlings for 1-5 years were larger in the pure forest than in the mixed forest, with the increase of age, the ground diameter of seedlings in Q. acutissima with P. tabulaeformis forest was slightly higher than the other two forest types, but the difference was not significant. The crown width for 2-10 ages was larger in the mixed forest than in the pure forest, and the differences were insignificant among the three forest types in 1-3 years but significant after 4 years. The height of the seedlings of 2-10 ages in the mixed forest of Q. acutissima with P. tabulaeformis was larger than in the mixed forest of Q. acutissima with broad leaved trees and in the pure forest of Q. acutissima. The differences of seedling height among three forest types became significant after 5 years. The biomass of leaves, stems, branches and roots of Q. acutissima seedling in three forest types all increased exponentially with age. The effect of forest types on seedling organic biomass depended on ages(but for root biomass). The effects on leave biomass were insignificant at 1-6 years of age and significant after 7 years, the effects on stem biomass were insignificant at 1-4 years and significant after 5 years, and the effects on branches biomass were insignificant at 1-2 years and significant after 3 years. However, the effect of forest types on seedling root biomass was independent with age. Conclusion: Q. acutissima populations among three representative forest types in Qiaoshan forest region were all developed well with adequate regeneration ability. Although the quantity of young seedlings in pure Q. acutissima forest was relatively high, the mortality rate was also rather high, and the growth characteristics and biomass of older seedlings were lower than that in the mixed forests. The number of larger individuals with high quality in mixed forests was more than that in pure forests. We concluded that the construction of mixed forests has higher wood productivity and more stable community structure, which should be the main direction for forest management in the future.

Key words: Quercus acutissima, population structure, habitat, growth characteristics, biomass

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