| Archidendron clypearia(Jack)Nielsen is a characteristic anti-inflammatory drug,its medicinal parts are dry branches and leaves(usually branches with base diameter of 3 cm),whether it is used traditionally or produced by modern Chinese patent medicines.Because of its less than 8 years history of plantation management,people still know little about its biomass,which is an important economic character index.Therefore,in this study,the biomass of three experimental plantations of A.clypearia in Liangkou county of Conghua district and Zhongluotan county of Baiyun districts in Guangzhou,and Liangjing county of Huiyang districts in Huizhou were taken as the research objects.Traditional biomass measurement method was used to establish the aboveground biomass distribution model of A.clypearia plantation through the measured data of the aboveground components(trunk,branches and leaves).Through the measured data of three sample plots,multiple biomass models were constructed,and the best models were selected to fit the general biomass model of the eastern pearl river delta.At the same time,20 trees were cut down in Huiyang,and a new random branch sampling(RBS)method was used to verify the accuracy and feasibility of estimating the aboveground biomass of A.clypearia.The main conclusions of this study are summarized as follows:(1)The results showed that based on the measured data of three plots,five candidate models were established respectively for the total biomass of branches,branch biomass and leaf biomass of each plot.fitted the relationship between D and W by 80 % data.the variance results of the five models showed that the P value was less than 10-4,and the relationship was extremely significant.But you and the effect of the total biomass model is the best,followed by trunk biomass,leaf biomass,five fitting model AIC calculation results show that equation fitting model AIC value is the smallest,followed by equation and equation.From the meaning of AIC,the fitted model has the least information loss among the five candidate models,is closest to the real model under the condition of given modeling data,has the most predictionability,and can explain the higher prediction accuracy of the model.The wi AIC values of the five candidate models also showed that the wi AIC values were 0.9889 and 1.0 in fitting the total fresh branches of single plot and the eastern pearl river delta region.Through comprehensive analysis,the power function model is the best model to predict the branch biomass of monkey earring plantation in this study.Moreover,the results show that RMSE is between 0.27 ~ 0.37,CF is between 1.14 ~ 1.20,and the model is stable.After selecting the best model,through the remaining 20 % data,the feasibility of the best model and the pearl river delta eastern general model is verified.through ME,MAE,MPE,TRE and MPSE five validation evaluation index,the comparison results of the three samples show that from MPE,the prediction accuracy is between 72 % ~ 77 %,Conghua up to 84 %.All of them have good generality,so the general model W = 0.1272 D2.0647 in the eastern pearl river delta is feasible,and can be used to estimate the biomass of Archidendron clypearia plantation.(2)Results showed that diameter an branch base is an appropriate auxilliary variable to be chosen in the conduct of RBS,and optimal results were obtained while its function coefficient of Z value was 2(i.e.the branch diamter square).The variances of RBS estimates increased with increasing number of the third order branches from the main shems with a coefficient of correlation of r =0.6393 at P=0.0006.This caused larger variances of estimates of crown biomass in elder individual trees and those with longer clear bole lengths which tend to prodce more third order branches.RBS crown biomass estimates with all possible paths selecetd recorded a relative standard error <3.5%,not theoretically zero but acceptable.Selection of 4-6paths produced 4.56%-5.45% of relative standard errors of the RBS estimates,and reduced2/3working load approximately(3)The crown biomass of A.clypearia.accounted for 75% of the total biomass above the ground,25% for the heights of the branches under the branches,58% of the aboveground biomass for the first branches,and 23% of the secondary shoots.The level of shoots only accounts for 2% of the above-ground biomass,and with the increase of the number of shoots,the correlation between the base diameter of the shoot and the biomass is getting lower and lower.The correlation coefficient between biomass of the first shoots is R2= 0.8078,thecorrelation coefficient between the biomass of the third-order shoots and shoots R2= 0.2944;and there is a significant correlation between the biomass of each component of the above-ground trunk level.The above-ground biomass allocation of the artificial forest was mainly stem(0.39)>leaf(0.34)>branch(0.18)>bakr of branch stem(0.05)>bark of main trunk(0.04),and the trunk occupied 39% of the total biomass of the aboveground part.The highest proportion,while the proportion of leaves accounted for 34%,the lowest proportion of the main trunk biomass was only 4%,the biomass of branch stems was slightly higher than that of main trunk,and the moisture content of branch stem skin was the highest,which is 69.25%,and branch stem has the lowest moisture content of 47.84%. |
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