Study On The Growth Law And The Community Characteristics Of Zelkova Schneideriana In Northwest Of Guangxi

The community and stem analysis of Zelkova schneideriana in Longlin County of Cuangxi were researched in this paper, its growth law and endangered reasons were studied in specific environmental, the characteristics of community and population structure were analysed. Based on the data and information, some protective measures were proposed to increase awareness of protection, provide scientific basis for promotion, development and utilization of this high quality tree species. The mail results were as following:(1) The natural growth of Zelkova schneideriana were fast, the growth trend of the near base diameter ere compared uniform, its rate was quick during young stage a nd stable after5years. The near base diameter growth rate in sixty-three years does not decreased with age, with an average of0.43cm/a.(2) The total growth of near base diameter(D) with old growth equation was D=1.08+0.369x-0.004x2+9.053x10-5x3.(3) The dominant species in the tree layer was Zelkova schneideriana. The deciduous species was more than evergreen species. Proportion of deciduous species was larger in hilly areas than in karst areas. The plant species and diversity of Zelkova schneideriana communities in non-karst areas was richer than in karst areas.(4) Natural regeneration of Zelkova schneideriana in non-karst areas was good, with more seedlings; while the populations was recession in karst areas. In non-karst areas the seedlings were cluster distribution and the number of seedlings distribution increased with age and gradually reduce.(5) The adaptability of Zelkova schneideriana was wide, the demanding of the soil was not strictly. Zelkova schneideriana grown well in both calcareous soil and acidic dry red soil. It also grown well in valley and lower slope position where had wet soil.(6) In the natural distribution area of Zelkova schneideriana, severe human disturbance and deforestation were the main reason of its endangered. According to its endangered causes, the author proposes to enhance publicity, consummate legal system, carry out ex-situ conservation, forest plantation, scientific research monitoring and other protection strategies.