RIRDC - Research Compendium 1993

Rural Industries
Research & Development Corporation

Research Compendium 1993 - 1994

Research Project

AGROFORESTRY WITH HIGH VALUE TREES

Objectives

To assess the growth potential of a number of high value rainforest trees when grown in plantation conditions under optimum conditions.
To determine appropriate planting densities at which some of these might be grown to yield both timber and pasture.

Background

Attempts have been made in the past to grow rainforest timber trees in plantations. Although some results were promising these early trials were effectively abandoned. Araucaria cunninghamii (hoop pine) was the only native rainforest tree to be included in an extensive planting program. The cessation of most logging in natural rainforests in Australia in the late 1980s has created a shortage of many of these timbers and there is now anecdotal evidence that their prices are starting to rise.

The project seeks to address two of the several issues needing resolution. One is - which of the many species present in rainforests are potential plantation candidates? The second is - how might these be grown by a landholder wishing to retain present pasture production while the trees and the pasture productivity at the various tree densities are being monitored.

Outcome

Of the sixteen species tested a least six have grown rapidly since the trial began while most others have grown reasonably well. The faster growing species include Cedrela odorata, Elaeocarpus grandis, Grevillea robusta, Rhodosphaera rhodanthema, Acacia melanoxylon and Flindersia brayleyana. These all grew more rapidly than Araucaria (which is currently being used in plantations) during the four year study period. It is known that Araucaria usually grows well after a slow start and this ranking may alter over the few years. Tree form varied within and between species and there is clearly scope for improvement.

The trees in the agroforestry trial have also grown well. The higher density plantings have begun to affect pasture production but a longer period of study is needed to observe the tree-pasture interaction.

Implications

The results show there are at least several Australian rainforest species with potential as plantation trees as well as several exotic species. The performance of these at a wider variety of sites now needs to be evaluated and more work is needed to develop appropriate silvicultural treatments for these.

RIRDC Project No: UQ-18A

RESEARCHERS: David Lamb and Geoff Borschmann

ORGANISATIONS: Botany Department

University of Queensland

BRISBANE QLD 4072

and

Greening Australia Qld Inc.

PO Box 9868

BRISBANE QLD 4001

PHONE: 07 365 2045

FAX: 07 365 1699