Effects of Forest Degradation on Forest’s Soil Water Retention in Northern Vietnam

• Main Author: Tran, Quang Bao
• Format: Article
• Language: English
• Published: ĐHQGHN 2017
• Subjects: Forest hydrology; Soil water retention; Soil moisture; Forest degradation.
• Online Access: http://repository.vnu.edu.vn/handle/VNU_123/56581
• Institution: Vietnam National University, Hanoi

This study characterized the forest soil water retention o f four forest types m Thuong Tien Natural Reserve, Northern Vietnam. Forty forest plots were designed to measure forest structure, topography, and soil properties. Daily soil moisture o f 40 plots and rainfall were collected in a period o f 60 consecutive days. Multi-linear regressions were used to inspect ứie relationship between forest structures, soil porosity and forest soil moisture. The environmental factors having sừong effect on forest soil moisture are litter cover, vegetation ground cover, and soil porosity. Forest soil moisture can be predicted by the two regression models. First, prediction model o f soil moisture for a rainy day (R^ ^0.55 - 0.81). Second, prediction model o f soil inoisiure for a no rainy day (R^=0.52 - 0.83). Main predictors o f these models are rainfall, antecedent soil moisture and time interval (days). The root square means eưor (RSME) o f the predicted values o the models is 2.03%. Forest soil water retention, a function o f soil moisture, soil depth and bulk density, varies among four forest types. The capability to retain water o f forest types ranks from moderate forest (401m m), in turn, rehabilitation forest (350mm), poor forest (346m ni), and mixed grass + shrub (249m m). Forest soil water retention also is monthly variability, mainly depending on annual rain regime. The highest capability o f water stored m soil is in August, and the lowest one is in February.