This study quantified the effect of weeding frequency and weeding schedules on weeding operation time in a sugi(Cryptomeria japonica)plantation stand.A weeding operation time estimation model was developed;then the cu...This study quantified the effect of weeding frequency and weeding schedules on weeding operation time in a sugi(Cryptomeria japonica)plantation stand.A weeding operation time estimation model was developed;then the cumulative weeding operation time after six growing seasons was simulated using the developed model.The developed model included weed height,relative height of weeds to sugi,and initial planting density.The simulated cumulative weeding operation time decreased approximately 6%for each one-treatment decrease in weeding frequency.Under a three-treatment weeding frequency scenario,the simulated cumulative operation time when weeding was conducted during non-consecutive years was longer than that when weeding was conducted during three consecutive years.The results suggest that carrying out weeding treatment during consecutive years is the more effective for reduction of weeding costs.We conclude that weeding schedule as well as weeding frequency must be considered for reduction of weeding operation time.展开更多
Mapping of deforestation,forest degradation,and recovery is essential to characterize country-level forest change and formulate mitigation actions.Previous studies have mainly used a simple forest/non-forest classific...Mapping of deforestation,forest degradation,and recovery is essential to characterize country-level forest change and formulate mitigation actions.Previous studies have mainly used a simple forest/non-forest classification after forest disturbance to identify deforestation and forest degradation.However,a more flexible approach that is applicable to different forest conditions is desirable.In this study,we examined an approach for mapping deforestation,forest degradation,and recovery using disturbance types and tree canopy cover estimates from annual Landsat time-series data from 1988 to 2020 across Cambodia.We developed models to estimate both disturbance types and tree canopy cover based on a random forest algorithm using predictor variables derived from a trajectory-based temporal segmentation approach.The estimated disturbance types and canopy cover in each year were then used in a rule-based classification of deforestation,forest degradation,and recovery.The producer’s and user’s accuracies ranged from 59.1%to 72.9%and 60.8%to 91.6%,respectively,for the forest change classes of mapping deforestation,forest degradation,and recovery.The approach developed here can be adjusted for different definitions of deforestation,forest degradation,and recovery according to research objectives and thus has the potential to be applied to other study areas.展开更多
文摘This study quantified the effect of weeding frequency and weeding schedules on weeding operation time in a sugi(Cryptomeria japonica)plantation stand.A weeding operation time estimation model was developed;then the cumulative weeding operation time after six growing seasons was simulated using the developed model.The developed model included weed height,relative height of weeds to sugi,and initial planting density.The simulated cumulative weeding operation time decreased approximately 6%for each one-treatment decrease in weeding frequency.Under a three-treatment weeding frequency scenario,the simulated cumulative operation time when weeding was conducted during non-consecutive years was longer than that when weeding was conducted during three consecutive years.The results suggest that carrying out weeding treatment during consecutive years is the more effective for reduction of weeding costs.We conclude that weeding schedule as well as weeding frequency must be considered for reduction of weeding operation time.
文摘Mapping of deforestation,forest degradation,and recovery is essential to characterize country-level forest change and formulate mitigation actions.Previous studies have mainly used a simple forest/non-forest classification after forest disturbance to identify deforestation and forest degradation.However,a more flexible approach that is applicable to different forest conditions is desirable.In this study,we examined an approach for mapping deforestation,forest degradation,and recovery using disturbance types and tree canopy cover estimates from annual Landsat time-series data from 1988 to 2020 across Cambodia.We developed models to estimate both disturbance types and tree canopy cover based on a random forest algorithm using predictor variables derived from a trajectory-based temporal segmentation approach.The estimated disturbance types and canopy cover in each year were then used in a rule-based classification of deforestation,forest degradation,and recovery.The producer’s and user’s accuracies ranged from 59.1%to 72.9%and 60.8%to 91.6%,respectively,for the forest change classes of mapping deforestation,forest degradation,and recovery.The approach developed here can be adjusted for different definitions of deforestation,forest degradation,and recovery according to research objectives and thus has the potential to be applied to other study areas.
