Landscape Pattern And Succession Of Chinese Fir Plantations In Jiangle County

Cunninghamia lanceolata(Lamb.)Hook It is a representative fast-growing tree species in the subtropical region of China,a unique timber tree species in southern China(south of Qinling Mountains),and the most important native coniferous timber tree species in China.Since the early 1980s,Chinese fir plantations have replaced evergreen broad-leaved forests on a large scale in southern China.After 40 years of large-scale afforestation,China has become the country with the largest area of plantation in the world.The area of Chinese fir plantation accounts for 12%of the forest in southern China,second only to Pinus massoniana,and is the main component of the forest landscape in southern China.In order to explore the current situation and development trend of landscape pattern of Chinese fir plantation after 40 years of artificial intervention and natural succession,this paper takes Jiangle County,Fujian Province,China as the research area,takes the forest resource survey data of three periods in 2010,2015 and 2020 as the analysis data,takes landscape ecology as the theoretical basis,and takes ArcGIS10.8,Fragstates4.2 and IDRISI17.0 as the technical support,The dynamic change of Chinese fir plantation landscape pattern from 2010 to 2020 was analyzed using transfer matrix and landscape index,and the CA-Markov model was built to simulate and predict the landscape pattern of Chinese fir plantation in Jiangle County in 2030.The main conclusions are as follows:(1)The landscape area,age group and spatial distribution characteristics of Chinese fir plantation:in the past ten years,the area of Chinese fir plantation in Jiangle County has shown a rapid growth trend,and the growth source is mainly young forest;The landscape of Chinese fir plantation shows an obvious juvenile trend,with the proportion of young and mid-aged forests increasing from 21%in 2010 to 49%in 2020,and the proportion of near-mature forests and mature forests decreasing from 50%in 2010 to 28%in 2020,resulting in a decline in landscape quality;The newly added Chinese fir plantation is expanding outward on the basis of the original distribution patches,and the distribution of Chinese fir plantation patches is gradually expanding to lower and higher elevations.(2)The characteristics of landscape quality change of Chinese fir plantation:in the past decade,the area of young and middle aged forests has been expanding,the fragmentation degree has decreased,the aggregation degree has increased,the patch shape has become increasingly complex,and the landscape quality has improved;The area of near-mature forest and mature forest is decreasing,the fragmentation degree is increasing,the aggregation degree is decreasing,the patch shape is becoming simpler,and the landscape quality is decreasing;The area of over-mature forest fluctuates and increases,the fragmentation increases,the aggregation decreases,the patch shape tends to be complex,and the landscape quality decreases.In general,the landscape quality of Chinese fir plantation in Jiangle County has decreased in the past ten years.(3)Characteristics of landscape transfer between Chinese fir plantation and other landscape types:the area of Chinese fir plantation has changed from evergreen broadleaved forest,deciduous broad-leaved forest,other coniferous forest,shrub forest,economic forest,non-forest land,other forest land and bamboo forest in the past ten years.Other coniferous forest and other forest land are the two landscape types with the highest conversion rate and the largest conversion area with Chinese fir plantation,while shrub forest and deciduous broad-leaved forest are the two landscape types with the lowest conversion rate and the least conversion area with Chinese fir plantation.The increased Chinese fir plantation mainly comes from other coniferous forests,other forest lands,non-forest lands and economic forests.The replaced Chinese fir plantation is mainly eroded by Phyllostachys pubescens.The zonal vegetation evergreen broadleaved forest has been effectively protected in the past 10 years.(4)The landscape pattern simulation of Chinese fir plantation in 2030 predicts that the landscape area of Chinese fir plantation in Jiangle County will continue to expand in 2030,mainly from non-forest land,economic forest,other forest land and other coniferous forests.In the future,the evergreen broad-leaved forest will continue to be protected,and the bamboo forest will continue to erode the Chinese fir plantation.