广西速生桉种植的空间分布及生态特征

广西是我国速生桉种植面积最大的省份之一,在大面积种植速生桉带来经济效益的同时,速生桉种植现状、生态特征及其环境影响也日益受到关注.基于第一次水利普查水土保持情况普查数据,以广西为例,综合分析了速生桉种植面积、空间分布及生态特征:1)广西速生桉种植面积已占到区国土面积的9.7%,并呈现“东南多西北少”的空间分布特点;2)广西速生桉林分布的平均坡度为20.4°,集中分布在8°~35°的坡面上,这与有林地坡度分布存在明显差异,有林地分布的平均坡度为26.9°,主要分布在大于25°的陡坡上;3)速生桉林分布的平均郁闭度为33.2%,有林地平均郁闭度为53.0%,速生桉的郁闭度相对有林地明显偏小,这与速生桉作为速生树种的特殊形态特征有关;4)速生桉林的平均盖度为61.9%,有林地平均盖度为81.1%,速生桉的盖度明显偏小. 

The spatial distribution of fast-growing Eucalyptus and ecological characteristics in Guangxi

Guangxi region has the largest area of fast-growing Eucalyptus plants in China.Considerable economic benefits come with wide planting of fast-growing Eucalyptus,therefore more attention has been focused on planting,ecological characteristics of and environmental impact on fast-growing Eucalyptus plants.Census data of the first Soil and Water Conservation Water Conservancy Survey in Guangxi were used to analyze planting area,spatial distribution and ecological characteristics of fast-growing Eucalyptus.Fastgrowing Eucalyptus has been found to be planted in 9.7％ of the province,with the feature of "more in the southeast than in the northwest".The average slope of fast-growing Eucalyptus forest in Guangxi was found to be 20.4°,concentrated on the slope 8°～35°.This was significantly different from the distribution of woodland slope,distribution of woodland averaged 26.9°,mainly on steep slopes greater than 25°.The average crown density of fast-growing Eucalyptus forest distribution was found to be 33.2％,forest canopy density average was 53.0％.Eucalyptus canopy density in woodland significantly was found to be smaller,which was related to the special morphological characteristics of fast-growing Eucalyptus as one of fast growing species.The average coverage of fast-growing Eucalyptus forests was 61.9％,woodland average coverage of 81.1％,coverage of fast-growing Eucalyptus was significantly less.