This study was conducted to evaluate the performance of six stem taper models on four tropical tree species,namely Celtis luzonica(Magabuyo),Diplodiscus paniculatus(Balobo),Parashorea malaanonan(Bagtikan),and Swieteni...This study was conducted to evaluate the performance of six stem taper models on four tropical tree species,namely Celtis luzonica(Magabuyo),Diplodiscus paniculatus(Balobo),Parashorea malaanonan(Bagtikan),and Swietenia macrophylla(Mahogany)in Mount Makiling Forest Reserve(MMFR),Philippines using fit statistics and lack-of-fit statistics.Four statistical criteria were used in this study,including the standard error of estimate(SEE),coefficient of determination(R^2),mean bias(E),and absolute mean difference(AMD).For the lack-offit statistics,SEE,E and AMD were determined in different relative height classes.The results indicated that the Kozak02 stem taper model offered the best fit for the four tropical species in most statistics.The Kozak02 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE,E and AMD in most of the relative height classes.These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height,merchantable stem volumes and total stem volumes of standing trees belonging to the four species of thetropical forest in MMFR.展开更多
This study was carried out to determine the performance of percentile-based Weibull diameter distribution model for Pinus thunbergii stands thriving along the eastern coast of South Korea. The parameter recovery techn...This study was carried out to determine the performance of percentile-based Weibull diameter distribution model for Pinus thunbergii stands thriving along the eastern coast of South Korea. The parameter recovery technique was used to estimate the three parameters of the Weibull model. The analysis demonstrated satisfactory results based on the following test statistics for the principal percentile models： fit index （FI） range from 0.501（minimum diameter） to 0.932 （50th diameter percentiles） and root mean square error （RMSE） range from 0.112 （quadratic mean diameter） to 3.572 （minimum diameter）. The developed model was further evaluated by determining the mean bias （E） in trees per ha （TPH） for each diameter class, and the results showed highest over-prediction in the 20 cm, and under-prediction in the x6 cm and 24 cm diameter classes. The goodness of fit tested by Kolmogorov- Smirnov （KS） test showed no significant differences （P〉0.05） between the observed and predicted diameter distributions for almost all plots. Using site index and aboveground biomass （AGB） models developed for P. thunbergii in South Korea, a model to predict the AGB per ha for each diameter class and subsequently the total AGB of the stand was created. An application guide was also created, which will serve as a decision-support tool for forest managers in quantifying the future total AGB in P. thunbergii stands located in the eastern coast of South Korea and, subsequently, the quantification of potential carbon stocks aside from being a vital input in designing efficient management and protection strategies for these stands.展开更多
基金support from Kongju National University Research Grant(2014)
文摘This study was conducted to evaluate the performance of six stem taper models on four tropical tree species,namely Celtis luzonica(Magabuyo),Diplodiscus paniculatus(Balobo),Parashorea malaanonan(Bagtikan),and Swietenia macrophylla(Mahogany)in Mount Makiling Forest Reserve(MMFR),Philippines using fit statistics and lack-of-fit statistics.Four statistical criteria were used in this study,including the standard error of estimate(SEE),coefficient of determination(R^2),mean bias(E),and absolute mean difference(AMD).For the lack-offit statistics,SEE,E and AMD were determined in different relative height classes.The results indicated that the Kozak02 stem taper model offered the best fit for the four tropical species in most statistics.The Kozak02 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE,E and AMD in most of the relative height classes.These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height,merchantable stem volumes and total stem volumes of standing trees belonging to the four species of thetropical forest in MMFR.
基金support from the Forest Science and Technology Projects(Project No.S211415L010140)provided by the Korea Forest Service
文摘This study was carried out to determine the performance of percentile-based Weibull diameter distribution model for Pinus thunbergii stands thriving along the eastern coast of South Korea. The parameter recovery technique was used to estimate the three parameters of the Weibull model. The analysis demonstrated satisfactory results based on the following test statistics for the principal percentile models： fit index （FI） range from 0.501（minimum diameter） to 0.932 （50th diameter percentiles） and root mean square error （RMSE） range from 0.112 （quadratic mean diameter） to 3.572 （minimum diameter）. The developed model was further evaluated by determining the mean bias （E） in trees per ha （TPH） for each diameter class, and the results showed highest over-prediction in the 20 cm, and under-prediction in the x6 cm and 24 cm diameter classes. The goodness of fit tested by Kolmogorov- Smirnov （KS） test showed no significant differences （P〉0.05） between the observed and predicted diameter distributions for almost all plots. Using site index and aboveground biomass （AGB） models developed for P. thunbergii in South Korea, a model to predict the AGB per ha for each diameter class and subsequently the total AGB of the stand was created. An application guide was also created, which will serve as a decision-support tool for forest managers in quantifying the future total AGB in P. thunbergii stands located in the eastern coast of South Korea and, subsequently, the quantification of potential carbon stocks aside from being a vital input in designing efficient management and protection strategies for these stands.
