Forests Of South-western Australia Research Articles

Early regrowth in rehabilitated bauxite minesites as breeding habitat for birds in the jarrah forest of south-western Australia

Summary A survey was undertaken lo assess 5 to 10-year-old rehabilitated bauxite minesite vegetation as suitable habitat for birds while breeding during spring in the jarrah (Eucalyptus marginata) and marri (E. calophylla) forest at Jarrahdale. Western Australia. The minesites had been rehabilitated and revegetated with local shrub species and a mix of local and eastern eucalypts resistant to the root rot fungus Phytophthora cinnamomi. Twenty-one species of birds used the former minesites for foraging or hunting while breeding; twelve of these were found nesting or rearing fledglings in the revegetation. Among the breeders were four understorey dwelling species which were otherwise uncommon in surrounding upland forest or (in two cases) confined in stream zone undergrowth. Total densities of all pairs or groups breeding in minesites were similar to those in nearby forest. Breeding territories often spanned areas of both minesite and forest around the edge of pits. Eleven other species were found breeding ...

Root Occupation and Root Channels of Jarrah Forest Subsoils

The role of root channels in the occupation of deep soil profiles by jarrah (Eucalyptus marginata Sm.) forest in south-western Australia was explored by coring and excavation. In profiles derived from granite, major descending roots are confined to channels that extend vertically from fissures and conduits in the shallow subsurface caprock layer deep in the clay subsoil. The channels are permanent features of the profile and are occupied by successive generations of trees. The channels have a diameter of 1-300 mm, abundance of 3 5 m-2 (all channels) or 1 m-2 (large channels), and occupy 1% of a horizontal surface at 6 m. Each forest tree has potential access to 100-200 channels. Large roots, fine roots with root hairs, and decaying root remains occur in the channels. Only fine roots (less than Imm diam.) penetrate the clay matrix and occupy the entire profile down to basement at depths of up to 40 m. In profiles derived from dolerite, occupation of the deep clay by large and fine roots is diffuse and root channels are absent. The dissimilar mode of root occupation of the two profile types may be explained by the difference in bulk density. In providing avenues for access by large roots as well as preferential wetting, the root channels may play a dominant role in the water and salt balance of jarrah forests on the granitic profile.

The structure and floristics of shrublands, woodlands and forests in South-Western Australia

The structure and floristics of shrublands, woodlands and forests in South-Western Australia

Morphometrics of the aerial roots of Kingia australis (Liliales)

Kingia australis, common in the heaths and forests of south-western Australia, is distinguished from all other grass trees in Australia by the presence of a mantle of concealed aerial roots. A ring of up to 50 root primordia is initiated in winter from the stem apex. In plants more than 1 m high, initiation and commencement of elongation of the primary roots are no longer annual but dependent on the fire history of the plant. These roots descend between the stem and persistent leaf bases at about 2 cm per growing month, sending many lateral branches among the leaf bases. Aerial roots gradually replace the space occupied by the leaf bases until they may account for 45% of the dry weight of the aerial caudex. The caudex of one 6-m-high specimen bore up to 27 roots per cm2 transection of the root mantle, with about 3000 primary roots entering the soil. All underground primary roots (except the initial contractile roots) have an aerial origin and are concentrated vertically under the canopy. After 300-400 years the stem starts to die back from the base, and the aerial roots attached to that portion disintegrate. By propping up the stem and bridging the dead zone of the stem, the living aerial roots greatly extend the potential height and longevity of the plant. In addition, the hairy laterals are ideally located to absorb water and nutrients directly from the leaf bases. Protective and aerating functions are also indicated.

Water quality and forests in Southwestern Australia: review and evaluation

Summary Water restrictions imposed during 1977 have focused attention on the adequac of Perth's water supply. However the deterioration of water quality through increasing salinizauon is at least as serious a problem, both now and in the future. Maintenance of a healthy forest cover, to which fresh water catchments are restricted, is crucial. But forests are being depleted by a range of causes, of which intensive forestry practices are one of the most important. The mechanisms by which soluble salts are redistributed in the landscape following forest clearing, and the severity of the effects where forests are to be regenerated, are the subject of dispute. This uncertainty, allied with the seriousness of the water quality situation, suggests that it is insufficient to merely monitor the situation to see what happens.