The recovery of tropical lowland rainforest after clearfell logging in the Gogol Valley, Papua New Guinea
Recovery of tropical rain forest in Gogol Valley, Papua New Guinea was monitored for 2 years following clear-fel1ing in the wet and dry seasons. Further redevelopment, reconstructed by measurements of regrowth of known ages from 1.5-10.8 years, were compared with forest heavily disturbed by fire 55 years ago and primary forest. The vegetation, survey was assessed principally by Counting and measuring trees. Because of the importance of soil seed bank in influencing vegetation recovery processes, special attention was given to the spatial and temporal changes in the soil seed bank and the seed rain which supplies it. The major findings were: (1) vegetation recovery was rapid and 97% of all colonizing trees regenerated from seeds while 3% were resprouts; (2) regrowth after felling in the dry-season differed from that following wet-season felling in having lower density, slower growth and mostly comprised resprouting tree species; (3) after 10 years, regrowth is composed principally of large pioneer trees (65% of basal area or 64% of stems); (4) the 55 year-old forest also had many (48%) pioneer trees: much of the forest in the area is of this kind and may be classified as advanced secondary forest; (5) forest soil seed bank following felling was rapidly depleted due to germination, but was rapidly replaced as early pioneer herbs matured and set seed. Trees in soil seed bank do not approach that of primary forest until after 10 years of regrowth; (6) the intensity of pioneer trees' seed rain was correlated with the fecundity of nearby parent trees and clearly controlled soil seed bank redevelopment. There was evidence of dispersal of pioneer seeds several hundred metres into an isolated area of closed forest; (7) trees left uncut following felling contribute significantly to seed rain and therefore to soil seed bank.