Soil Moisture Conditions in Four Types of Forests in Kampong Thom, Cambodia

Soil moisture conditions were observed in four types of forest in central Cambodia, where dry evergreen forests are distributed widely, to investigate differences of soil moisture in each forest and to clarify relationships between forest types and soil moisture conditions. Observations revealed that soil water contents were high during the rainy season in dry deciduous forest (DDF) and mixed forest (MF), which contained both evergreen and deciduous trees. Those areas have thinner tree crown density and less stand biomass than a dry evergreen forest (DEF). In contrast, during the dry season, water content was low in DDF and MF. That difference is attributable to the disparate evapotranspiration rates of forests caused by the tree crown density and stand biomass. Moreover, soil temperatures were affected by the type of forest. In areas with DDF forests, the temperatures were high in the months of April and May but were lower in MF, DEF, and DEFlog forests. Those differences were caused by inhibition of temperatures through shading effects of tree crowns and evapotranspiration by trees. Based on those observed data, this study clarified a relationship between forest stand type and soil moisture conditions in Kampong Thom forest area.