广州城区公园风景游憩林径级和高度级结构分布

【目的】探明广州风景游憩林群落结构现状以及存在的问题,进一步为城市风景游憩林群落结构调整和配置优化提供理论依据。【方法】以900 m^2样方为单元分别在广州发展公园风景游憩林群落样地设置样方15个,华南农业大学风景游憩林群落样地设置样方25个,火炉山森林公园风景游憩林群落样地设置样方20个,采用群落生态学的方法,研究了不同生态位风景游憩林径级和高度级结构分布。【结果】1)3个样地风景游憩林径级结构呈现一定差异:广州发展公园以大、中径级乔木占绝对优势,华南农业大学样地风景游憩林小径级乔木相对优势明显,火炉山样地风景游憩林群落以中、小径级乔木占绝对优势。2)根据群落中个体的胸径和树高呈现不同的相关关系表明:广州发展公园样地风景游憩林大径级树木开始出现衰退现象;华南农业大学样地风景游憩林由于存在大量小径级的速生树种,导致胸径—树高曲线在初期迅速增高;火炉山样地风景游憩林结构配置拟自然化,胸径—树高曲线增长较为平稳。【结论】根据高度级比重、相对频度和分布均匀度分析结果得出:广州发展公园样地风景游憩林中、大高度级树木比重较大,且分布更为集中,华南农业大学样地风景游憩林的小、中高度级的树木所占比重较高,小高度级树木分布更为集中;火炉山样地风景游憩林小高度级比重,且分布更为集中。建议通过人工择伐、补植特定树种的方式,调控城市风景游憩林群落的径级和高度级结构分布,促进风景游憩林的逐步稳定。

Distribution of the diameter and height class structure for landscape recreational forests in the urban parks of Guangzhou

【Objective】To clarify the distribution of diameter and height class structure in different ecological niches of landscaperecreational forests,【Method】15 sample plots in the Guangzhou development park,25 sample plots in the South China Agricultural University and 25 sample plots in the Huolu mountain forest park landscape-recreational forests were selected by the method of community ecology.【Result】1)Of the total study region,there were differences in the diameter class structure of the landscaperecreational forests.The large and medium diameter class trees had been a dominant position in Guangzhou development park,the small diameter class trees had been a dominant position in South China Agricultural University,and the medium and small diameter class trees had been a dominant position in Huolu mountain forest park.2)The correlations of the DBH and tree height indicated that the large diameter class trees belonged to the landscape-recreational forest of Guangzhou development park had been experiencing recession;the DBH-height relationship had a rapidly rising at the beginningin the landscape-recreational forest of South China Agricultural Universitydue to large amount small diameters class trees with fast-growing;the landscape-recreational forest of Huolu mountain forest park had a naturalized structure which leads to a relative stabilization in the DBH-height relationship.【Conclusion】It was concluded that in the Guangzhou development park,the ratios of medium and large height class trees were more than the others;while in the South China Agricultural University,the proportion of small and medium height class trees were higher,besides the distribution of small height class trees was more concentrated;and small height class trees in the Huolu mountain forest park were more than others.It was suggested that artificial selective cutting and replanting specific tree species should be proposed to regulate the diameter and height class structure aiming to promote the gradual stabilization of landscape-recreational forests.