秦岭皇冠暖温性落叶阔叶林优势树种的径级结构和数量特征

Diameter structure and quantitative characteristics of dominant tree species in warm temperate deciduous broadleaf forest plot in Huangguan of Qinling Mountains,China

该研究以秦岭皇冠暖温性落叶阔叶林25hm2森林动态监测样地为研究平台,以样地内4个优势树种(锐齿槲栎(Quercus aliena var. acutiserrata)、栗(Castanea mollissima)、油松(Pinus tabuliformis)、华山松(Pinus armandii))为研究对象,运用数量分析等方法对4个优势树种的年龄结构和数量动态特征进行分析,以期揭示种群的生存现状,预测种群的发展趋势。结果显示:锐齿槲栎、油松和华山松种群个体数随胸径增大而减少,幼龄林木个体数较多,自然更新能力较强;栗种群的径级结构呈“正态”分布,幼龄个体少,后期结构较稳定。栗种群小径级个体的存活率是该种群更新和发展的关键,初步推断种子的留存情况主要受到动物取食和人为影响,进而影响种群的更新,因此需进一步了解栗种群种子的留存情况,加强对小径级个体的生长监测,提高其存活率和生存质量。锐齿槲栎、油松和华山松3个优势树种的存活曲线均更符合Deevey-II型,其幼龄个体数具有一定优势,但个体死亡率也较高。3个优势种群不同的生存状况反映了其生存能力的差异,总体上表现为幼龄个体在整个种群中占据优势,但随着时间的推移,个体的生长存活受到周围生物与非生物环境的影响。该研究对秦岭优势树种种群数量特征等进行了详细描述,为进一步探讨种群发展提供数据支持。

Aims Four dominant tree species in Huangguan of the Qinling Mountains,China,were chosen for a detailed examination of their diameter structures and quantitative characteristics.This investigation sought to elucidate the survival status of these populations,offering essential insights for their conservation and management.Methods We conducted a comprehensive analysis of the population characteristics of these four dominant tree species by mapping their diameter structure,constructing static life tables,and fitting survival and mortality curves.We employed a time sequence analysis model to predict the population’s future development.Important findings The analysis of diameter distribution revealed that the number of individuals for Quercus aliena var.acutiserrata,Pinus tabuliformis and Pinus armandii populations decreased with increasing diameter at breast height(DBH).These populations exhibited abundant juvenile stages,indicating robust natural regeneration ability.In contrast,the diameter structure of the Castanea mollissima population followed a“normal”distribution,with fewer juvenile individuals and a stable structure in later life stages.For this population,the survival rate of individuals with small diameter is crucial for renewal and development.It is inferred that seed retention in the Castanea mollissima population is mainly affected by animal feeding and human activities,subsequently impacting population renewal.Therefore,a deeper understanding of seed retention in Castanea mollissima population is necessary.Monitoring the growth of individuals with small diameter is essential to improve their survival rate and overall quality.The survival curves of Quercus aliena var.acutiserrata,Pinus tabuliformis and Pinus armandii primarily conformed to the Deevey-II type,indicating a predominance of juvenile individuals but also a higher mortality rate among them.The distinct survival conditions among these three dominant populations reflected differences in their survivorship abilities.Overall,juvenile individuals predominated in the entire population,but the growth and survival of individuals were influenced by biotic and abiotic factors in their surroundings.This study provides a comprehensive portrayal of the population characteristics of dominant tree species in Qinling Mountains,offering valuable data for further investigations into population development effects.