Comparative Analysis Of Growth Characteristics And Comprehensive Benefits Of Three Species Of Acacia Crassicarpa,Michelia Macclurei And Betulaalnoides

Excellent fast-growing species and rare native species has been the focus of Guangxi forestry science and technology promotion work,has a very high economic benefits,social benefits and ecological benefits,the study is of important significance to find out the future promotion work,make forestry technology extension more targeted and better promotion effect.In 2009 the central government forestry science and technology demonstration fund projects in Gaofeng Ping Fu breakout established in middle Guangxi Acacia Crassicarpa,Michelia macclurei,Betula alnoides demonstration forest as the research object,growth characteristics and comprehensive benefits of three tree species were comparatively systematically analyzed,to find out the advantage and direction for each species for the future,to Guangxi forestry science and technology extension work more provide scientific basis and technical support for.The main findings of this study are summarized as follows:(1)Acacia crassicarpa,the tree height,DBH and individual volume growth was the highest among three tree species,tree height is 11.66m,diameter is 11.67cm,the volume were 0.06716m3/fand beads.The felling age was 6 years,5 years of economic benefit is 3926.13 yuan/hm2 years;planting Acacia Crassicarp per hectare per year to provide 16.7 jobs to the community and the masses to drive around 467hm2,the ecological benefits of three species is the highest.Acacia Crassicarp short rotation,Guangxi has a.history of growing economic benefits,although not southwestbirch is high,but the characteristics of low cost,periodic points,quick returns,farmers are more likely to accept,Acacia Crassicarp has the effect of nitrogen fixation,improving soil,understory vegetation rich,suitable for the general fanners or economic conditions land is barren place.(2)Betula alnoides,the tree height,DBH and individual volume growth of three tree species in the middle,tree height is 10.56m,diameter is 9.83cm,the volume were 0.04444m3/fand beads.The rotation for a period of 20 years,5 years of economic benefit is 6436.27 yuan/hm2,is the three highest economic benefit;planting southwestbirch per hectare per year to provide 6.1 jobs to the community,to drive the other branch forest planting 67hm2,drive people around planting 133hm2;ecological benefit in three species in the middle.The economic benefit of planting Betula alnoides is far higher than that of the other two species,but it has a long cycle and higher cost.It is suitable for long-term investment of forest farmers,companies or enterprises with pure forest in the economic base.(3)Michelia macclurei,the tree height,DBH and individual volume growth were the lowest among three tree species,tree height 6.66m,diameter 7.91cm,volume 0.01905m3/fand beads.The rotation for a period of 25 years,5 years of economic benefit for the-1327.53 yuan/hm2 year,planting Michelia macclurei per hectare per year to provide 3.3 jobs to the community,to other forest ecological benefits of planting 133hm2 field,is the lowest of the three species.Michelia macclurei rotation,understory,and itself also has the fire protection effect,5 years of economic benefit for the lowest pure forest or mixed forest of long-term or combination of long and short term investment,or to non profit for the purpose of fire belt planting.