Study On Biomass Model For Pulp Eucalyptus Plantations

Forest biomass is the weight of all dry matter accumulated during the production and metabolism of forests,and it is the energy base and material source for the operation of forest ecosystems.Forest biomass not only reflects the characteristics of forests in material circulation and energy flow,but also can be used to describe the operating conditions and utilization value of forests.It can also be used to accurately assess and predict forest ecosystem service functions.This paper took the Eucalyptus plantations of Jijia Forest Farm of Leizhou Forestry Bureau as the research object,conducting the field investigation in March-April 2017,and divided and plotted the wood sample and fallen timber in 30sample plots,and used SPSS19.0,EXCEL2010 statistical software for data processing,fitted the incompatibility model of biomass of the above-ground total amount,the trunk,wood,bark,crown,branch and leaf of tree and stand of Eucalyptus plantations.Based on the incompatibility model,the compatibility model of biomass of the total above-ground,the trunk,wood,bark,crown,branch and leaf of the Eucalyptus plantations were constructed by the simultaneous nonlinear equations model,and discussed the characteristics of biomass allocation of 1-5 years old Pulpwood Eucalyptus plantations.The results provide a theoretical basis for estimating the biomass of Eucalyptus plantations and estimating the carbon storage of Eucalyptus plantations,and provide valuable reference for the important functions of Eucalyptus plantations in the process of ecological restoration in Leizhou Peninsula.The main study results show:(1)Whether single wood or forest stand,biomass of the above-ground total,trunk,wood,bark,crown,branch and leaf of Pulpwood Eucalyptus plantations increase with the age of trees.The total amount of above-ground biomass of 1-5 years old individual tree is 2.379?11.029?16.245?40.352?62.164 kg/?.The total amount of above-ground of 1-5years forest stand is 4.056?21.595?55.220?24.208?68.660 t/hm~2.Due to the significant reduction in the planting density of 4-year-old Eucalyptus plantations,the biomass of this stand age is relatively reduced.(2)Pulpwood Eucalyptus plantations,whether individual trees or stands,aboveground biomass consists of four parts,trunk(including wood and bark),canopy(including branch and leaf),and percentage of biomass at each site as a percentage of total biomass above ground.The trunk biomass accounts for more than 70%of the total above-ground biomass,and the proportion of crown biomass of the total above-ground biomass is close to 30%.The percentage of the total biomass of each part of the above-ground biomass can be expressed as wood>branch>leaf>bark.Wood biomass is the largest,accounting for about60%of the total biomass above the ground.The biomass of the branch is the second largest,accounting for about 16%of the total biomass on the ground.The biomass of leaf accounts for about 12%of the total biomass on the ground.The biomass of the bark is the smallest and the proportion of the total biomass on the ground,less than 10%.