Study Of Leaf Area Size And Vertical Distribution For Larix Olgensis Plantation In Heilongjiang Province

The object of this study was Larix olgensis plantation,which came from Mengjiagang forest farm,Dongjingcheng forest farm and Linkou forest farm in Heilongjiang Province,respectively.Based on the measurement of 756 first-order branch samples from 76 planted Larix olgensis trees in 11 plots,the predicting model of first-order branch leaf area(BLA)was modelled.After that,a further knowledge of crown leaf area(CLA)model was developed.The two-parameter Weibull distribution function was introduced to develop the model of leaf area vertical distribution compared with the Johnson's SB distribution function.The results were as follows:1.The BLA was closely related to its own attribute factors(branch base diameter(BD)and branch length(BL)).A form of InBLA=?1+(?2+b2)lnBD+(?3+b3)lnRDINC+?4lnDBH+?5ln(HT/DBH)+(?6+b6)lnCR was selected as the optimal BLA mixed-effect model introduced variations in trees(?i were fixed coefficients,bi were random-effect coefficients,RDINC was the relative depth into crown from tree apex,DBH respresented tree diameter at breast height,HT/DBH was the ratio of tree height to DBH,CR was the ratio of crown length to tree height).The Ra2,RMSE,ME,MAE and P of the optimal BLA mixed model were 0.90,0.5477,-0.03,0.24 and 91%respectively,which could get a good effect on fitting and predicting.2.The data of CLA was calculated via the sum of predicted BLA by using the developed BLA model above.Lots of atttibute factors of trees were found that being related to CLA closely,such as HT,DBH,crown length(CL),HT/DBH.The optimal CLA model was a traditional regression model for likelihood ratio tests showed that the random effect of plot was unnecessary(p>0.05).The specific form was as follows:lnCLA=?o+?1lnDBH+?2CR.The regression model of CLA performed well in the aspect of fitting and predicting,which Ra2,RMSE,ME,MAE and P were 0.85,0.3847,-0.08,0.31,93%respectively.3.Compared with Johnson's SB distribution,the Weibull distribution could get a better fitting of vertical distribution of leaf area in per tree.The relative location of maximum leaf area in the crown(RNDICmax)was near the middle of the crown,concentrating from 0.45 to 0.61 of RDINC mainly.A series values of scale parameter(wi)and shape parameter(w2)were estimated by the maximum likelihood estimation in per tree,and the predicting models of wi and w2 with attribute factors of trees and stands were developed based on a group of wi and W2.A strong relationgship between wi and stand age,CL was founded by developing the w1-predicting model,the performance of fitted was so-so with the walues of Ra2 and RMSE were 0.46 and 0.0853,ME,MAE,and P were 0.15,0.15,and 80%,respectively for wi model;a high correlation between shape parameter(w2)and the growth level of the tree in the stand,which meant the competition in the stand had an effect on w2.The related statistical factors of model fitted and tested Ra2,RMSE,ME,MAE,MAE were 0.31,0.1182,-0.08,0.38,91%,respectively.Both the predicting model of wi and w2 couldn't get a good effect on fitting and prediction statistically,however,it could provide a theoretical support for further analysis of the leaf area vertical distribution.