Seasonal and long‐term soil water regime in West African tropical forest

Abstract

Abstract. Variation of soil matric potential of a Wet Evergreen and a Moist Semi‐deciduous West African forest were compared. The two forest types differed strongly in their soil water regime. Wet Evergreen forest experienced matric potentials below −100 kPa only occasionally, while in Moist Semi‐deciduous forest matric potentials were less than −2.5 MPa for periods of several weeks or more each season. A water balance equation was used to simulate the soil water regime at both sites and predict severity and length of the dry period. The predictions showed good agreement with the field measurements of soil water potential over a 2‐yr period. The methodology was used to estimate the occurrence and severity of droughts over longer periods at the two sites. The balance calculations suggest that droughts occur occasionally in the Wet Evergreen forest under study. The potential impact of droughts on species distribution and vegetation disturbance in tropical forests is discussed.