广西喀斯特地区黄枝油杉林的生境及种群结构特征

Habitat Condition and Population Structure Characteristics of Keteleeria calcarea Forest in Karst Area of Guangxi

关键词:  黄枝油杉  生境状况  土壤养分  群落  种群  高度结构  冠幅结构  径级结构

Key words:  Keteleeria calcarea  habitat condition  soil nutrition  community  population  height class structure  crown width class  age class structure

摘要:

为调查珍贵树种黄枝油杉Keteleeria calcarea在广西的生境状况和种群结构特征，保护并可持续利用该物种，本研究采用样地调查法对黄枝油杉群落进行调查，分析其生境状况、土壤营养成分、伴生植物组成、种群结构特征等。调查结果显示，黄枝油杉在广西主要分布于喀斯特石山地区，从山顶至山底均有分布，亦可见于石山底部与土山相连的土石交错区，常见于阳坡或半阳坡，分布区土壤为黑色石灰土、棕色石灰土或黄土，呈酸性、中性或弱碱性，有机质和全氮含量较高，有效磷含量较低。黄枝油杉群落植被状况良好，可分为乔木层、灌木层和草本层，层间植物丰富，不同群落在物种组成上存在较大差异；黄枝油杉为乔木层的优势种，一般呈集群分布，偶见少数几株或单株分布于路边或房前屋后；少数种群因设有保护小区而种群状态较好，但是仍有部分种群人为干扰较为严重。不同种群个体的高度结构、冠幅结构和径级结构存在一定差异，恭城三江和富川麦岭种群以中老龄个体较多，融安泗顶种群以中龄个体居多，而临桂二塘种群以中小个体占优势，4个种群均存在幼苗缺乏、种群更新能力弱的情况，呈衰退趋势。生境的破坏、资源的过度采伐、结实植株数量少以及林下幼苗更新困难是黄枝油杉濒危的重要原因。因此，应加强对黄枝油杉资源和生境的保护，同时加强相关科研工作及黄枝油杉的推广应用。

Abstract:

The habitat status and population structure characteristics of Keteleeria calcarea were investigated in the karst area of Guangxi for the protection and sustainable utilization of this species.According to the method of field investigation,the general situation of sample plots,soil nutrition composition,habitat status,associated plants composition and population structure characteristics were analyzed.The investigation results show that K.calcarea is mainly distributed in the karst stone-mountain area in Guangxi,and it is distributed from the top to the bottom of the mountain.It can also be found in in the earth rock cross area between the bottom of the stone-mountain and the earth mountain.It is common in sunny or semi-sunny slopes.The soil in distribution area is black lime soil,brown lime soil,or loess,which is acidic,neutral,or weakly alkaline,with high organic matter and total nitrogen content,and low available phosphorus content.The vegetation of the community of K.calcarea is in good condition,which can be divided into tree layer,shrub layer and herb layer with abundant inter-laminar plants,and there are significant differences in species composition among different communities.K.calcarea is the dominant species in the tree layer,and it is generally distributed in clusters.Occasionally,a few plants or individual plant are located on the roadside or behind the house.The minority population has a better protection by setting up protection communities,while some populations have more serious human interference.There are some differences in height structure,crown width structure and diameter class structure of individuals in different populations.The Gongcheng and Fuchuan populations are mostly middle-aged or elderly individuals,the Rong'an population is dominated by middle-aged individuals,and the Lingui population is dominated by small and medium-sized individuals.The four populations are all in the situation of lacking seedlings and having weak population renewal ability,showing a declining trend.Destruction of habitat and excessive logging of resources,small number of fruiting trees and difficulty of regeneration of seedlings under the forest are the important reasons for the endangerment of the K.calcarea.It is necessary to strengthen the protection of the resources and habitats of K.calcarea, and to strengthen related scientific research and the promotion and application of this species.