Study On Vegetation Succession In Hunan Province

Since the reform and opeing up policy carried out more than30years,especially the natural foreset protection project in1999, the vegetation succession in Hunan province has a very welcome change. The mountain turns green and forest coverage rate is increased. Some developed hilly areas which have good soil conditions has been recovered well. For examples:The hilly region in Changsha Xiangtan Zhuzhou and Loudi has transformed into lush forest from deserted red soil and bare mountain. Northwestern Hunan, such as the limestone mountainous in Longshan county, was once stone mountain of bared or thatched mountain, now become the thickets after closure. If then through decades of banned, it can become forest, but the restore process will last long time. At the same time, we also found some problems in the field investigation: the purple soil area of Hengyang basin, poor vegetation, nearly desert; Chenzhou basin limestone hills, a few total for the thatched, although by many afforestation, but can't forest, extremely easy come under fire, causing the vicious cycle; In Some counties like Huaihua city in low mountains, the mountain afforested by cunninghamia lanceolata, due to no mother deciduous species and bottom plants are all damage, leading to restore vegetation extremely difficult; Some site conditions which is good deforested and give up business to bring about vine plants spread quickly and bamboo violently, lead to other trees can't reach and productivity is extremely low, ecological benefit is very poor. Because lack of understanding the feature of tree spices, the original build plantation, such as Cryptomeria japonica var. sinensis and Cupressus funebris forest, formed a "green desert", can't play a variety of forest benefit. In this paper. The Hunan forest vegetation succession of a preliminary study, and the results are as follows:1. The research on hilly region's forward suceession: Liuyang hilly area as an example. Survey6samples, three of which are coniferous forest, two coniferous and broad-leaf forest, an evergreen broad-leaf forest. Represented in hilly red soil region of Liuyang, the vegetation succession order is bare soil or sparse vegetation, the coniferous forests dominated by Pinus massoniana, coniferous and broad-leaf mixed forest, evergreen broad-leaved forest. Recommended that the method of ban to protect and recover the vegetation.2. The vegetation succession study on middle and top mountain area:mount Hengshan as an example. Select six samples, including2shrublands,3broard leaved forest, an mountain top elfin forest and a artificial Cryptomeria japonica var. sinensis forest. The research shown that the vegetation in middle and top mountain area succession order is: burned land or shrubland---shrub-grassland with large number of Lespedeza bicolor---deciduous shrubland---deciduous broad-leaved forest---evergreen broad-leaved forest. Climax community type depended on the altitude, terrain and slope difference.3. Hunan province vegetation degradation caused by the destruction of the forest vegetation, mainly in two aspects:First, a large number of vine growth in low mountain and hilly area; the second is the rapid spread of dwarf bamboo in the province-wild. Degradation of the site, resulting in tree in tree species can't be base on. The possibility of recovery or succession order of its vegetation are unable to predict temporarily.4. There are two type of artificial conifer pure forest in Hunan forest, Cryptomeria japonica var. sinensis forest and Cupressus funebris forest. They have strong reproductive and occupation ability, resulting in low levels of biodiversity. The understory litter are few and ecological and economic benefits are poor. We recommend that restrict the development of these two types forest strictly. Gradual transformation of the formation of broad-leaved forest.5. Phyllostachys edulis forest has high economic value, expanding in Hunan province in the last20years, a large number of broad-leaved forest was replaced by Phyllostachys edulis Forest, resulting the water storage function of forests decline seriously, and low levels of biodiversity. From the current study, broad-leaved forest is very easy to be replaced with Phyllostachys edulis Forest, but Phyllostachys edulis Forest natural succession to the broad-leaved forest is still unknown.6. The study on vegetation succession in Hengyang purple land area: due to the human activities and shallow soil, the purple soil region's vegetation is extremely poor, very difficult to restore, and more in the shrub stage, rare forest vegetation. The recovery method is strictly banned and supplemented by artificial afforestation, select species suitable for the purple soil region. 7. The study on vegetation succession in Chenzhou basin limestone area:the limestone areas of vegetation succession can be divided into herbaceous stage, shrub stage, shrub stage, deciduous forest stage and evergreen coniferous and broad-leaf mixed forest stages. Rook desertification in Chenzhou district is very serious. The governance approach to the banned, supplemented by artificial afforestation. Cyclobalanopsis glauca, Castanopsis sclerophylla, Lindera megaphylla, Cyclobalanopsis gracilis, Liquidambar formosana can be the dominant species in tree layer.