Treefall Gap Dynamics in a Tropical Rain Forest in Papua New Guinea

Treefall gaps play important roles in tropical rain-forest ecology. But studies rely increasingly on models, remote sensing, and a few intensively studied research sites, mostly in the neotropics. We studied the basic parameters of gap dynamics (size, causes, and frequency) of treefall gaps in a lower montane primary forest on the southern flank of the central range of Papua New Guinea. We found 40 treefall gaps formed on 10.4 km of transect sampled annually over 3 yr. Mean proportion of forest under new gaps was 0.015/yr. Mean area of treefall gaps ≤1 yr old was 312 m², and gap area was positively correlated with diameter of the fallen tree. Mostly only large trees (diameter at breast height [DBH] x̄ = 53 cm) fell as snapped (n = 23) or uprooted (n = 17), creating both single (n = 34) and multiple (n = 6) treefall gaps. There was no strong directionality in the bearings of treefalls. This study provides some of the first information on gap dynamics in Papua New Guinea, where such data can be used to inform sustainable forestry harvesting practices.