目前,黄土高原五台山槲树种群在天然次生林中越来越占优势,而油松正在下降。在本论文中,直径等级(而不是年龄)被用来将不同的生长阶段分类为青少年,亚成人,或成人,并利用单变量函数g(r)分析了黄土高原三个1公顷树永久地块空间格局和种间关联的动态变化,中国西北。我们的结果表明,生态位宽度随发展阶段而变化。直径分布曲线符合倒“J”型,表明自然再生在所有三个地块中都很常见。空间格局和尺度之间有着密切的关系,在小的距离上表现出明显的聚集,随着距离的增加变得更加随机,但在松树+槲树混交林中,整个物种聚集在50m的距离内。空间结块的程度从少年到亚成年,从亚成年到成年。不同生长阶段的空间格局也不同,可能是由于强烈的种内竞争。不同生长阶段之间的关联在小尺度上呈正相关。我们的研究对于了解Q的发展很重要。五台山海森林;因此,在规划黄土高原森林经营和制定恢复策略时,应更加关注空间动态变化特征。
Quercus wutaishansea populations on the Loess Plateau are currently becoming more dominant in natural secondary forests, whereas Pinus tabulaeformis is declining. In the present paper, the diameter class (instead of age) was used to classify the different growth stages as juvenile, subadult, or adult, and the univariate function g(r) was used to analyze the dynamic changes in spatial patterns and interspecific associations in three 1-ha tree permanent plots on the Loess Plateau, NW
China. Our results suggested that the niche breadth changed with the development stage. The diameter distribution curve was consistent with the inverted \"J\" type, indicating that natural regeneration was common in all three plots. There was a close relationship between the spatial pattern and scale, which showed significant aggregation at small distances, and became more random as distance increased, but in the Pinus + Quercus mixed forests, the whole species were aggregated at distances up to 50 m. The degree of spatial clumping decreased from juvenile to subadult and from subadult to adult. The spatial pattern also differed at different growth stages, likely due to strong intraspecific competition. Associations among different growth stages were positively correlated at small scales. Our study is important to the understanding of the development of the Q. wutaishansea forests; thus, the spatial dynamic change features should be received greater attention when planning forest management and developing restoration strategies on the Loess Plateau.