Study On Plant Species And Community In Scrub Construction On The Side Slope Of Chongqing Express Loop Highway

During the course of the highway construction,quarrying a mountain on a large scale to get the rock and take the soil has formed a mass of exposed side slopes,which has destroyed the original vegetation and initiated a series of serious bad results.A large number of research work has been carded on in the field of the theory and the technique of vegetation restoration in the road side slope in our country and foreign countries.However,the related research has still serious lags comparing with the instant development of the road in recent years.Chongqing is a typical mountainous city and has unique geography condition and extremely rich side slope plant resources.However,there are few researches on the vegetation restoration of the road side slope in Chongqing,especially in the field of shrub construction,causing to lack of the theory and the practice instruction.This paper has selected the plant species and the collocate pattern of plant community which are suited to shrub construction in the side slope of Chongqing Express Loop Highway,through the summery on domestic and foreign countries' theory of vegetation restoration in road side slope,the survey of plant community on the side slope in the around areas of Chongqing Express Loop Highway,the dynamic track survey of plant community on the side slope after scrub construction, and the planting trial of seven young shrub.The results showed as follows:(1) The main dominant local shrub and young trees on the side slope in the around areas of Chongqing Express Loop Highway are as follows:Vitex negundo,Rhus chinensis,Rosa laevigata, Viburnum Chinshanense,Myrsine africana,Pyracantha fortuneana,Rubus eorchorifolius, Phyllostachys heteroclada,Lespedeza bicolor,Rhamnus heterophylla,Gardenia jasminoides, Melastoma normale,Glochidion puberum,young Quercus fabri,young Mallotus barbatus,young Robinia pseudoacacia,young Broussonetia papyrifera,and so on.(2) The main vegetation types on the side slope in the around areas of Chongqing Express Loop Highway are as follows:①Evergreen needle-leaved forest,for example Form.Pinus massoniana;②Deciduous broad-leaved forest,for example Form.Quercus fabri,Form.Robinia pseudoacacia,etc.;③Mixed needle-leaved forest,for example Form.Pinus massoniana+Cinnamomum camphora;④Broad-leaved thicket,for example Form.Vitex negundo, Form.Rhus chinensis,Form.Broussonetia papyrifera,etc.;⑤Grassland,for example Form. Arthraxon hispidus,Form.Imperata cylindrica,Form.Flos chrysanthemi,etc.(3) The planting trial of seven plants:the growth status of Indigofera amblyantha and Robinia pseudoacacia are best;Vitex negundo,Leucaena glauca and Crotalaria pallida are better;Amorpha frutieosa and Koelreuteria bipinnata are worse.(4) The dynamic track survey of plant community on the side slope after scrub construction shows:①The average relative growth rate of the target plants are in turns:Cosmos bipinnatus＞Robinia pseudoacacia＞Vitex negundo＞Indigofera amblyantha＞Leucaena glauca＞Amorpha fruticosa＞Koelreuteria bipinnata;②Robinia pseudoacacia,Vitex negundo and Indigofera amblyantha are most suit to grow in the side slope of Chongqing Express Loop Highway and having better landscape;Koelreuteria bipinnata and Amorpha fruticosa are little suit to grow in the side slope;Crotalaria pallida are not suit to grow in the side slope;Cosmos bipinnatus,a kind of annual herbage,whose growth status are fine in early days while the seed sprout rate is low in ensuing year, can become the early plant of vegetation restoration in the side slope.Although the quantity of Cosmos bipinnatus are few in later days,it can increase landscape of the side slope.(5) The optional floristic of scrub construction are as follows:①Young trees(nine kinds): Robinia pseudoacacia,Broussonetia papyrifera,Koelreuteria bipinnata,Pinus massoniana,Quercus fabri,Ficus virens var.sublanceolata,Ficus microcarpa,Mallotus barbatus,Sapium sebiferum ect.;②Shrub(twenty kinds):Vitex negundo,Amorpha fruticosa,Indigofera amblyantha,Leucaena glauca, Indigofera pseudotinctoria,Rhus chinensis,Lespedeza bicolor,Syringa pubescens,Cassia corymbosa,Rhododendron simsii,Photinia serrulata,Phyllostachys heteroclada,Pyracantha fortuneana,Myrsine africana,Rosa laevigata,Rubus corchorifolius,Loropetalum chinense, Melastoma normale,Gardenia jasminoides,Viburnum Chinshanense.etc.;③Herbage(ten kinds): Cosmos bipinnatus,Medicago Satival,Flos Chrysanthemi,Arthraxon hispidus,Imperata cylindrica, Miscanthus sinensis,Festuca ovina,Heteropogon contortus,Cynodon dactylon,Deyeuxia arundinacea etc.;④Liane(nine kinds):Rosa multiflora,Bougainvillea spectabilis,Pueraria lobata, Hederae sinensis,Parthenocissus tricuspidata,Lygodium japonicum,Millettia dielsiana,Smilax china,Lonicera japonica,etc.(6) The scrub community of scrub construction is as follows:①Form.Indigofera amblyantha +Vitex negundo+Amorpha fruticosa;②Form.Indigofera amblyantha+Robinia pseudoacacia+ Leucaena gtauca;③Form.Robinia pseudoacacia+Vitex negundo+Leucaena glauca;④Form. Indigofera amblyantha+Leucaena glauca+Robinia pseudoacacia+Vitex negundo;⑤Form.Vitex negundo+Broussonetia papyrifera;⑥Form.Vitex negundo+Pyracantha fortuneana+Myrsine africana,etc.