Canopy tree mode of death in a western Ecuadorian rain forest

Abstract

All dead trees ≥ 20 cm DBH were counted in the first 6 mo of 1994 in 10 ha of wet lowland rain forest, in the Hoja Blanca Hills, western Ecuador. The trees were classified by their mode of death. Thirty-four per cent of the trees were uprooted, 35% had snapped, 15% had died standing and 16% were unclassified. Regression analyses found that slope position and whether an individual was a dicotyledonous tree or a palm (Iriartea deltoidea) to be both strongly related to the mode of death. Slope, altitude and the presence of buttresses also influenced the mode of tree death. Tree diameter, however, was not found to have any effect. Dicotyledonous trees predominantly uprooted and snapped while Iriartea mostly died standing and snapped. Uprooted and snapped trees were significantly spatially clumped while trees which died standing were distributed at random. It was concluded that the predominance of uprooting and snapping in Hoja Blanca mostly resulted from the steep terrain and high precipitation (c. 5000 mm y⁻¹) as well as El Niño Southern Oscillation (ENSO) downpours. The implications of mode of death are discussed. The different modes created different types of gaps and could thereby potentially influence forest regeneration.