Research On Forest Community And The Choice Of Species Of Limestone Mountains In South Of Anhui

Because of its barren, clayish and shortage of effective water besides inappropriate choice of species over the years, mismanagement, and human destruction, there were lots of barren hill and"old but small"stands.The auther intended to find some suitable tree species and the models of reforestation in different site types, based on the investigation on the vegetation, soil physical and chemical characters and the site types of secondary forest communities and plantation forest communities on limestone hills. The experiment sites distributed in 13 cities and counties of the south of Anhui province. The study results would help for speeding up the afforestation in the barren mountains, enhancing the productivity of forest, protecting and developing the existing natural secondary communities of limestone mountain area. The main study results were as follows.The limestone mountain soils of south of Anhui were classified into five types. They were thickness layer of brown lime soil, middle brown lime soil, thin brown lime soil, stony lime soil, and black lime stone lime soil.The result of the analysis of physical and chemical characters of the soils showed that the pH value of brown lime soil was between 4.4 and 7.58. It showed acidic to neutral response, and Ca and Mg content was not high. The pH value of stony lime soil was 8.09, being alkaline reaction, with lower of Ca and Mg contents. The pH value of black lime soil was between 7.18 and 7.6, being neutral to alkaline reaction, with bit higher contents of Ca and Mg comparatively.The main cover types of natural secondary communities on limestone mountain in south of Anhui were Com. Quercus acutissima-Vitex negundo, Com. Liquidamba formosana-Phyllostachys heteroclada, Com. Liquidamba formosana- Loropetalum chinense, Com. Pinus massoniana- Junipetus formosana , Com. Pistacia chinesis- Pleioblastus amarus,Com. Ilex putpurea Hassk- Phyllostachys heteroclada,Com. Quercus phillyraeoides- Camellia fraterna,Com. Liquidamba formosana- Pleioblastus amarus,Com. Quercus acutissima- Pleioblastus amarus,Com. Pinus massoniana-Phyllostachys.,Com. Liquidamba formosana- Loropetalum chinense,Com. Liquidamba formosana- Lindera glauca,Com. Quercus acutissima,Com. Pistacia chinesis- Lindera Reflexa, Com. Castanea mollissima- Serissa serissoides,Com. Pinus massoniana- Loropetalum chinense,Com. Quercus acutissima-Phyllostachys.,Com. Castnopsis sclerophylla- Lindera Reflexa,Com. Pinus massoniana,Com. Liquidamba formosana- Lindera Reflexa. .According to some dominant environment factors such as soil type, soil thickness, rocky exposed rate, mountain direction, inclination, slope position etc., the stand sites of the limestone mountains in the south of Anhui were divided into seven site types: stone exposed, shallow soil lawns, lamina brown lime soil slope stand,middle brown lime soil slope stand, thick layer of brown lime soil slope,hummock,downfold stand, rocky groove soil slope stand, mountaintop black lime soil stand, stony lime soil slope stand .Base on the investigation of vegetation conditions both of natural secondary communities and plantations communities, we selected some tree species suitable to forestation on limestone mountains in the south of Anhui province. They were Quercus acutissima , Liquidamba formosana, Pistacia chinesis, Quercus aliena, Pinus massoniana, Pinus elliottii, Platycladus orientalis, Junipetus formosana, Pteroceltis tatarinowii, Quercus phillyraeoides,Ilex putpurea Hassk. Chooseing different tree species to fit in diffirent site and microenvironment.The paper also provided reforestation models applying for different classification of stand site and the present conditions of communities. First model was artificial aids reforestation. In large rocks exposed areas, and the ridge or a steep slope uphill areas, the fertilizer conditions was bad, and lack of the mother forest resources. The main effect ion of forest was protecting the soil and holding water, but not cultivate the low productive Timbers. These shrubbery should be keeped and managed. We should protected the seedlings of Platycladus orientalis, Junipetus formosana, and the species of the family Fagaceae , Liquidamba formosana and Pistacia chinesis.The second reforestation model was the combination of natural and artificial regeneration. It was suitable for the mountain slopes existing small areas of trees and the sparse arbor areas, for maintain the functions of preserving the natural environment water and soil, existing vegetation, prevent become stone mountains. The mothed was replanting appropriate trees, or small area clear-felling with combination of artificial and natural, so that the natural environment be restored and improved.The third reforestation was transformation of low-yielding forest. Since the productivities were not high in south of Anhui currently. Some forests seriously harmed by disease and insect, stability were poor, for example Pinus massoniana, Pinus elliottii, Cunninghamia lanceolata, Junipetus Formosan, Platycladus orientalis, and lead to "small but old" forests. Those stands should be planned and step-by-step adaptation. The fourth reforestation was artificial afforestation. It was selecting suitable species in stand of better conditions to afforestation.