Study In Southwest Of Two Different Regeneration Patterns Of Eucalyptus Plantations Of Economic Growth

In recent years, the supply of timber market is not adequate to the demand. This phenomenon makes the development of plantation has been accelerated. Eucalyptus has the feature of fast growing, straight trunk, good material and so on. Eucalyptus, one species of myrtaceae, is one of three major world recognized species of fast-growing. Guangxi has the largest area of Eucalyptus plantations.Based on the 4 years and planting density of 2500/hm2 and 1250/hm2 and two different regeneration pattens of Eucalyptus plantation in Guangxi southwest, compares and analyses indicators of growth conditions, productivity, volume, stock volume, nutrient content, soil physical and chemical properties and economy effectiveness, that hoping to provide reference for Eucalyptus plantation management. The main findings are as follows:(1) Because of planting density and update mode, the indicators of growth conditions, biomass and productivity of Eucalyptus sprout forests are better than planting seedlings forest. Planting seedlings forest varies in the number of trees diameter class, appearing most in the 12 cm.(2) There are some difference between two different regeneration pattens. the planting density of 2500/hm2 and 1250/hm2 of Eucalyptus plantation The volume of average tree of seedlings is 0.0779 m3 and 0.0865 m3, sprout forest are 0.0983 m3 and 0.1120 m3 respectively; the volume of Eucalyptus plantation of seedlings are 162.1503 m3 and 95.5310 m3, sprout forest are 191.6153 m3 and 119.5471 m3 respectively.(3) Each organ biomass and productivity of seedlings and sprout forest, that size from large to small:trunk> branch> bark> leaf. Meanwhile, their accumulation amount of each nutrient element size and efficiency are varies. The nutrient accumulations of seedlings are 967.60 kg/hm2 and 565.80 kg/ hm2 respectively; sprout forest are 954.85 kg/hm2 and 527.73 kg/hm2. In addition to the accumulation of K element, other elements accumulations of seedlings are higher than those sprout forests. However, sprout forests produce It dry bud nutrients needed less than planting forest. The forest soil bulk density increases with the soil deepen. Other stand soil physical property and all sorts of content of organic matter with the soil depth are reduced. Among that, N element content of the highest forest soil and followed by the P element.(4) Each planting of Eucalyptus plantation profits are 33984.11/hm2、 17776.07/hm2. Density From evaluation index of economic benefits of Eucalyptus afforestation project, which in two kinds of regeneration pattern, that the net margin, net annual profit rate of investment and internal rate of return of 4 years eucalyptus planting forests are less than planting seedlings forest. And the sprout payback period is shorter than planting forests. Which indicating that profits can be obtained more quickly sprout after forest plantation investment, and bringing better economic efficiency.