North Queensland Naturalist 50: 55-64


Rose Gum (Eucalyptus grandis) is a tall, fast-growing eucalypt which, in north Queensland, occurs in upland wet sclerophyll forest. The tree provides important habitat for wildlife; in particular, large specimens provide hollows which are used as dens by the vulnerable Wet Tropics Yellow-bellied Glider (Petaurus australis unnamed subspecies). The Tumoulin Forest Reserve near Ravenshoe is home for both Rose Gum and the glider but has a history of logging such that large hollow trees are now scarce. Triggered by concern that den trees are vulnerable to fire and storm damage and might not be readily replaced, we investigated the diameter of Rose Gums in and around the Reserve along seventeen transects each with 20 trees. Rose Gum diameter varied strongly between transects but not with geology (basalt, rhyolite) nor position (edge, roadside, forest interior). Eight known den trees in the Reserve had a mean diameter of 151 cm and a minimum of 95 cm. Very few trees along transects matched these diameters but trees in the 50 to 100 cm diameter class – potential replacements den trees in the foreseeable future ­– were patchily dispersed and occasionally abundant. An assessment of Rose Gums at the scale of glider territories may be needed to ascertain prospects for the future development of den trees.