Seasonality and Phenology in a Dry Tropical Forest in Ghana

Abstract

(1) Flowering, fruiting, leaf production, leaf fall and girth changes all show a strong seasonal pattern in a tropical forest and grassland/thicket mosaic in Ghana. Moisture deficits limit phenological activity although patterns vary among species. (2) Flowering and fruiting occur throughout the year. Dry-fruited species fruit principally in dry seasons. Fleshy-fruited species fruit in either wet or dry seasons, although fleshy fruits are most abundant in wet seasons. Species grouped according to habitat and life-form show similar patterns of flowering and fruiting. (3) Leaf flushing is entirely limited to wet seasons, although not all species or individuals produce new leaves each wet season. Leaf fall occurs in dry seasons; 19% of forest species and 55% of grassland/thicket species became fully leafless during the study period. (4) Girth changes are closely related to rainfall and foliage phenology. The amplitude of girth changes is related to the habitat of the species, with greater seasonal changes occurring under more exposed conditions. Net girth increments over the 15-month period were negative, due to the unusually low rainfall.