Regeneration of a North Queensland Rain Forest Following Felling and Burning

Abstract

The regeneration modes and heights of 82 tree species reappearing the felling and burning of a tropical rain forest were observed 23 months the perturbation. Of these species, 74 had coppiced, 10 had produced root suckers, and 34 had developed from seed during the post-fire period. Those trees developing mainly from seed appeared to have the highest growth rates. The results are discussed in relation to the stability of the floristics of the tree component on the site and the problem of predicting successional sequences in the tropical rain forest environment. STUDIES OF SECONDARY SUCCESSION have been seen as essential for a solution to the problems of establishing a rational system of land use in the tropics (Richards 1955). In his study of secondary plant succession in tropical montane Mindanao, Kellman (1970) stressed that the first critical question to be answered when explaining a successional sequence was autecological. Unfortunately, autecological data for the species involved in secondary successions in the tropics are often not available. The object of this paper is to illustrate the importance of an autecological characteristic, the regeneration mode of a species felling and burning, on the floristic composition of the regenerating stand. The 100 x 100 m felled and burnt plot forming the basis for this study was established as one treatment of an experiment examining the effects of various silvicultural alternatives on the growth of planted seedlings of Flindersia brayleyanal and F. pimenteliana. The study was commenced only when it was observed that many components of the original rain forest had regenerated by coppice. Although seedlings and root suckers of some tree species in the original stand were also present, they appeared to be of lesser overall significance. The only previously published quantitative study of regeneration following severe disturbance to a tropical or subtropical rain forest in Australia is that of Williams et al. (1969). They cleared their experimental area with a bulldozer, exposing mineral soil over most of the area. The observations they made were of seedling regeneration, and the few coppice shoots were ignored. Workers outside Australia also seem to have concentrated on aspects of seedling regeneration. Nevertheless, sufficient mention is made of coppice development in the literature on secondary succession in the tropics to indicate that this feature is widespread if not universal. For example, Symington (1933) in a Malayan forest observed that after felling, coppice growth, if allowed to develop, will within a few years create a stand which, except for the absence of large trees and the presence of a few typical secondary growth species, shows little indication that the rainforest had been so recently cleared. Whitmore (1975) in his review of rain forests of the Far East mentions the coppicing habit mainly in relation to rain forests with one or more limiting environmental factors, e.g., the heath, swamp, and mon-