桂西南岩溶地区森林类型及生态平衡

The Forest-types and Forest Ecosystem of the Limestone Hills in South-west Guangxi

广西西南部碳酸盐岩岩溶地区,自然资源丰富而独特,森林被复率达90%以上,在全世界也属罕见.因而,研究该地区的森林类型、生态平衡及生态系统等问题,在理论上与生产实践上都有重要意义.

There are three forest-types are recognized:1.)Basin north-tropical rain forest community.This forest-type is situatedon the basin of the limestone hills,the hydrolized light-brownish calcareoussoil is rather thick,PH 6.5,limestone outcrop is not frequent.For the favorof the water contain and the fertile soil,the forest community is very flourish.This forest-type is an excellent physiognomice of tropical rain forest.2.)Slope north-tropical evergreen forest community.This fore-st-typelocated on the slope of the limestone hills,the upper limit is not exceeded alt,400m..It is the largest forest-type,and as well as is a typical representationalso.The ground is covered with 80%,limestone outcrop.The soil is scanty ofbrownish calcareous soil,totally about 10—20%,PH 6.8—7.5.This forest-typeis not a rain forest or a monsoon forest,but a evergreen forest.3.)Ridge thickets community.This forest-type distributed above alt.250-400m.on the ridge of the peak.The habitat is full of rocky outcrop,only very scantysoil diposited on the gap of rocky outcrop,the total cover about 50%,it isbrownish or primary calcareous ones,PH 7-7.5.This forest-type com Fosed of2-4m.high shrubs and are xerpphytic in appearance,the trunks are shorteningand curve,the barks are thicken and rough,and the surfaces of the leaves coveredwith thickly cuticle or hairy.The relationship between the forest-types and their habitat is closely relatedand complicated,and the ecological balance is tending towards stability.Theyconstituted a limestone hills forest ecosystem and a complex food-net(Fig.1.2.).About 1300 species of the preducers was found in this ecosystem.The consumersof this ecosystem including 117 species or subspecies of land vertibrate animal,and436 species of insects.The reductors of this ecosystem consist of 47 species and 2subspecies of fungi during dry-season.But this ecosystem is very fragility,it willbecome desert-type or bare-type ecosystem and difficult to recorver,when theywere destroyed.So that,it must be to maintaining the ecological balance,to deve-loping the ecological superiority,and able to obtaining the maximum ecologicaleffect and the economical benefit.