Plant responses and herbivory following simulated browsing and stem cutting of Combretum apiculatum

Time and mode of herbivory on savanna trees and their subsequent responses are dependent on, among other things, earlier herbivory and fire. We used c lipping (simulated browsing) and stem cutting (simulated heavy browsing and to some extent simulated fire) to evaluate such interactions. Study organi sms were a deciduous, broad-leaved tree species, Combretum apiculatum (Comb retaceae), browsing large herbivores and leaf-eating insects. The treatment s were done in the late dry season before bud break. Late in the following wet season, we recorded plant responses to treatment and browsing. The trea ted trees, especially the cut ones, responded by producing larger and fewer annual shoots. Compared to control trees, there was a slight increase in s hoot biomass of clipped trees and a strong reduction of cut ones. Leaf area increased in clipped trees, but decreased in cut ones. A marked increase i n the number of browsed trees was recorded amongst treated trees. Number of bites, consumption and utilization also increased with severity of treatme nt. In contrast, insect herbivory was reduced on both clipped and cut trees . The observed patterns are discussed in relation to current ideas on plant - herbivore interactions.