The Cultivation Of Acarcia Tree Species On Coastal Sandy Site And The Application In Protection Forest

Being short of coastal sandy land forestation species, bad system stability, faint resistance, seriousplant diseases, we proposed to cultivate Acacia tree species which had extensive adaptability and strongresistance to typhoon and arid site. We also applyed Acacia tree species to coastal protection forest systemconstruction. There are vital significances in resolving productivity and land fertility declination, improvingthe protection forest species structure and forest stand special structure, increasing the resistance ability andprotection effects. Since 20 centuries 70's, we have carried out Acacia tree species cultivation experimentand application in coastal protection forest in the Chishan State-owned Protection Forestry Farm ofDongshan County. The results are as follows:1) The adaptability of Acacia crassicarpa, A. aulacocarp and A. mangium and so on five Acacia treespecies was strong, which can generally adapt the bad condition of coastal sandy land. They had strongabilities for soil fertility maintenance and improvement. It could enrich the protection forest tree species,beatify coastal forest landscaping and fulfill forestland sustainable use. Acacia crassicarpa grew quickly.The Acacia crassicarpa's resistance ability of gale, typhoon and arid were strong.2) The study of Acacia tree species cultivation on coastal protection forest indicated that, Acaciacrassicarpa, A. aulacocarpa and A. mangium were suit to growing in the back coastal fringe sandy land.The average height exceeded 1.0 m.a-1; DBH growth exceeded 1.0 m.a-1. Otherwise, Acacia crassicarpagrew quickly, forest stand closed early, and had stronger adaptation ability to the sandy gale, the drift sandand the serious drought. They were ideal species to the cutting land of bone shelterbelt and the gustydifficult sandy land.3) Acacia crassicarpa and Casuarina mixed forest grew well; Crown structure layers were reasonable,and formed the obvious multiple structure. The root system in the horizontal and vertical directiondistribution and the quantity were different; root density was different at different soil level. The Acaciacrassicarpa and Casuarina mixed forest was more advantageous for the forest stand photosynthesis and thenutrient effective absorption. At the same time, the total biomass, average productivity, leaf area index andleaf only assimilation rate of the mixed forest were all higher than the simple Casuarina forest species' andthe simpl Acacia forest species'.4) After Acacia tree species planted in the coastal sandy land, they could obviously enhance thecontents of the hydrolyze nitrogen, fast-acting kalium, effective phosphorus, entire nitrogen and the entire carbon. At the same time, the different Acacia tree species were different in enhancement these effectivenutrient contents and improvement supplies condition.5) Compared with continuously cultivation Casuarina, Acacia could reduce the soil capacity, increasethe porosity, strength the water capacity, enhance the content of entire carbon, entire nitrogen, ammoniumnitrogen, hydrolyze nitrogen and elevate the soil PH, which caused the soil positive ion exchange totalquantity reducing. When using Acacia to forestration, other enzyme activeness were all elevation except atthe level of 0～20cm and 20～40cm.6) Summing up the experiences, we proposed the application patterns that Acacia tree species shouldplant in the back coastal fringe sandy land, in the shelterbelt cut land and in the gusty area difficult site.These experiences could provide the reference for further practice.