The Response And Simulation Of The Biomass Of Larix Principis-rupprechtii Plantation In Liupan Mountains To Site Condition And Stand Structure

Site condition and stand structure have direct and indirect effects on tree growth.As an important indicator of growth,the dynamic change of biomass reflects the response of trees and stands to site condition and stand structure.Based on the survey information of 23 sample plots and the biomass data of 110 sample trees,organ,aboveground and individual biomass models were established.The effects of different site conditions and stand structure on organ,individual plant and stand biomass were determined,and the biomass prediction and calculation model considering the influence of site conditions and stand structure factors were established.1. A biomass model for organ compatibility of Larix principis rupprechtii in Liu Pan Mountain was established:W=0.073D^2.51?W=0.017?D²H?^0.822;Aboveground biomass model:W=0.055D^2.548?W=0.034?D²H?^0.930;Model of trunk biomass:W=0.034D^2.613?W=0.020?D²H?^0.956;Branch biomass model:W=0.014D^2.452?W=0.009?D²H?^0.890;Leaf biomass model:W=0.014D^2.058?W=0.011?D²H?^0.731;Root biomass model:W=0.021D^2.339?W=0.014?D²H?^0.843?2. The changes of the organ,individual plant and stand biomass with the main site conditions and stand structure factors are as follows:?1?the biomass of trunk,branch,root and individual plant increases slowly with the increase of forest age,and then increases rapidly,which is in line with the changes in the early and middle stages of tree growth.With the increase of forest age,leaf biomass first increases rapidly,but the growth rate slows down,which may be due to the accumulation of dry matter mainly through photosynthesis in the low forest age stage.With the increase of stand age,stand biomass presents a slow,fast,and slow"s"growth curve.The results showed that when the dominance was less than-0.3,the biomass of trunk,branch,leaf and individual plant increased slowly;when the dominance degree was between-0.3 and 0,the biomass of trunk,branch,leaf and individual plant increased rapidly;when the dominance degree was greater than 0,the biomass of trunk,branch,leaf and individual plant increased slowly.With the increase of dominance,the growth rate of root biomass decreased slowly.?3?When the stand density is less than 1100 plants/hm²,the biomass of branch,leaf,and single plant increases slowly with the increase of stand density,while the biomass of trunk and root decreases slightly,and the biomass of stand increases rapidly.In the range of stand density 1100-1500 plants/hm²,the biomass of organ and single plant decreases slowly,and the stand grows slowly When the stand density is more than 1500 plants/hm²,the biomass of organ and single plant decreases rapidly,and the standing biomass tends to be stable.?4?The response rule of organ,individual plant,and stand biomass to altitude are the same.They all rise slowly at first,reach the peak at the altitude of 2300m,and decline slowly at the altitude of 2300-2500m.When the altitude is more than 2500m,the biomass declines rapidly.?5?The main law of biomass change with slope direction is that the growth of the trunk,individual plant,and stand biomass is better in the shady slope and semi-shady slope.3.A multi factor prediction model was established to predict the biomass growth potential without field measurement.The results show that the coupling model can greatly improve the fitting accuracy of the original model,and broaden the adaptability of the model under different site conditions and stand structure.This research result will provide scientific method support for accurate calculation of needle biomass of Larix principis rupprechtii plantation in Liupan Mountain.