雾灵山自然保护区胡桃楸种群结构特征分析

胡桃楸群落是雾灵山自然保护区森林植被的典型类型之一,分布在海拔700~1 400 m的阳坡.根据雾灵山自然保护区胡桃楸种群不同龄级结构设置两个样地,通过对胡桃楸种群每木必测,采用种群径级结构代替年龄结构,不同的生境条件分析雾灵山自然保护区胡桃楸种群结构及动态变化特征.结果表明:(1)雾灵山自然保护区胡桃楸种群结构呈"金字塔"型,种群中幼树和中龄树所占比重大,表现为稳定型种群,种群个体数目基本随径级的增加而减少;(2)存活曲线接近Deevey-Ⅲ型,高径级种群趋于稳定,种群具两个死亡高峰,中龄树种群的死亡率高达80%,这是由于中龄树个体较多,在共同的生境条件下争夺生存空间和资源,群落树种互相竞争影响下,死亡率较高;(3)龄级分布与微地形的关系密切相关,坡度在30°~40°范围中胡桃楸种群龄级分布较广泛,海拔高度在800 m~1 000 m范围中胡桃楸种群各龄级分布广泛,幼树和中龄树数量多,而在其它海拔高度范围中受土地利用类型和生境条件的影响,分布的龄级数目少.

Characteristics of Population Structure Juglans Mandshurica from the Wuling Mountain Nature Reserve

Juglans community Wuling Mountain Nature Reserve is one of the types of forest vegetation typical,located at an altitude of 700 ～ 1 400 m sunny.According Wuling walnut age classes of the population structure set up two plots,through walnut wood must be measured for each species,instead of using the population age structure,size structure,analysis of different habitat conditions walnut Wuling Mountain Nature Reserve population structure and dynamic characteristics.The results showed that：Population structure Wuling walnut was ＂ pyramid＂ type,population saplings and mature trees in the major share,the performance of stable population,the number of individuals in a population base with increasing diameter class reduction; Survival curves approaching Deevey-Ⅲ type,height and diameter class populations stabilized,with two deaths peak population,the mortality rate in the age group of trees up to 80%,which is due in large mature trees individuals in common habitats competitive space and resources,community species compete with each other under the influence of a higher mortality rate ; Age class distribution is closely associated with the micro-topography,slope at 30.～ 40.Range Juglans wider population age class distribution,altitude 800 m ～ 1 000 m range Juglans species widely distributed in each age level,saplings and mature trees in quantity,while in other altitude ranges by land use types and habitats conditions,the distribution of the small number of age classes.