The study was conducted to develop height-diameter at breast height(HT-DBH) models for Alnus japonica in La Trinidad, Benguet,Philippines and evaluate their predictive capability.The six widely used nonlinear growth m...The study was conducted to develop height-diameter at breast height(HT-DBH) models for Alnus japonica in La Trinidad, Benguet,Philippines and evaluate their predictive capability.The six widely used nonlinear growth models that were selected in this study were the ChapmanRichards, Schnute, Modified logistic, Korf/Lundqvist,Weibull and Exponential. A total of 208 Alnus japonica trees were measured using standard diameter tape for DBH(1.3 m above the ground) and Vertex and transponder was used for the total height measurement. The performance of the developed models were evaluated using the fit statistics including coefficient of determination(R^2), root mean square error(RMSE), mean bias(ē), absolute mean difference(AMD), and Akaike Information Criterion(AIC). The lack-of-fit statistics was also performed for further evaluation of the performance of the models.Based on the evaluation criteria, all six models were able to determine the DBH-height relationships and fitted the data well. Using the rank analysis, the Weibull HT-DBH model had the best performance among the six commonly used nonlinear growth models. The results of this study will help forest managers especially in La Trinidad, Benguet to easily predict the total height using the Weibull model for Alnus japonica utilizing the DBH as the predicting variable.展开更多
Water resources assessment in poorly gauged and ungauged basins demand supportive rainfall-runoff estimation, while resolving practical water resource management and planning issues. In this study, the research method...Water resources assessment in poorly gauged and ungauged basins demand supportive rainfall-runoff estimation, while resolving practical water resource management and planning issues. In this study, the research method employed involves rainfall-runoff modeling and simulation with proper efficiency criteria evaluation using the MODMENS modeling platform, a numerical rainfall-runoff semi-distributed GR2M conceptual lumped model. The rainfall-runoff simulation was carried-out in three selected sub-basins of Lower River Niger Basin based on observable discharge dataset. Related error estimation was carried-out to estimate the runoff simulation uncertainty while model optimization approach entails use of Rosenbrock-Simplex method and model reliability evaluation entails the use of Nash and Sutcliffe efficiency criteria methods. Result shows a satisfactory model performance at Baro and Makurdi gauging stations （savannah ecological zone） while under-estimation characterizes simulated flow at Onitsha gauging station（Forest ecological region）. Seasonally, the model best fit the dry season flow but underestimate during the high flow periods （rainy seasons and wetter years）.展开更多
基金support of the Forest Science and Technology Projects [Project Nos. 2013069D10-1819-AA03 and 2014068E10-1819-AA03] provided by the Korea Forest Service
文摘The study was conducted to develop height-diameter at breast height(HT-DBH) models for Alnus japonica in La Trinidad, Benguet,Philippines and evaluate their predictive capability.The six widely used nonlinear growth models that were selected in this study were the ChapmanRichards, Schnute, Modified logistic, Korf/Lundqvist,Weibull and Exponential. A total of 208 Alnus japonica trees were measured using standard diameter tape for DBH(1.3 m above the ground) and Vertex and transponder was used for the total height measurement. The performance of the developed models were evaluated using the fit statistics including coefficient of determination(R^2), root mean square error(RMSE), mean bias(ē), absolute mean difference(AMD), and Akaike Information Criterion(AIC). The lack-of-fit statistics was also performed for further evaluation of the performance of the models.Based on the evaluation criteria, all six models were able to determine the DBH-height relationships and fitted the data well. Using the rank analysis, the Weibull HT-DBH model had the best performance among the six commonly used nonlinear growth models. The results of this study will help forest managers especially in La Trinidad, Benguet to easily predict the total height using the Weibull model for Alnus japonica utilizing the DBH as the predicting variable.
文摘Water resources assessment in poorly gauged and ungauged basins demand supportive rainfall-runoff estimation, while resolving practical water resource management and planning issues. In this study, the research method employed involves rainfall-runoff modeling and simulation with proper efficiency criteria evaluation using the MODMENS modeling platform, a numerical rainfall-runoff semi-distributed GR2M conceptual lumped model. The rainfall-runoff simulation was carried-out in three selected sub-basins of Lower River Niger Basin based on observable discharge dataset. Related error estimation was carried-out to estimate the runoff simulation uncertainty while model optimization approach entails use of Rosenbrock-Simplex method and model reliability evaluation entails the use of Nash and Sutcliffe efficiency criteria methods. Result shows a satisfactory model performance at Baro and Makurdi gauging stations （savannah ecological zone） while under-estimation characterizes simulated flow at Onitsha gauging station（Forest ecological region）. Seasonally, the model best fit the dry season flow but underestimate during the high flow periods （rainy seasons and wetter years）.
