Vegetative propagation and preliminary field performance of sixteen rainforest tree species in north Queensland

Abstract

This study assessed sixteen rainforest tree species, from nine taxonomic families, for amenability to vegetative propagation (VP) via rooted cuttings, as a possible means for overcoming constraints on seedling deployment of these species that were considered to have potential for plantings of various kinds. Elaeocarpus grandis and Cedrela odorata (the latter being the only exotic species included) were found to be highly amenable to VP. Several other species (Acacia aulacocarpa, Agathis robusta, Alloxylon flammeum, Araucaria cunninghamii and Gmelina fasciculiflora) exhibited sufficient potential such that, if improvement in key propagation traits could be achieved in the future, then VP may become a viable deployment strategy for these species as well. In contrast, Blephocarya involucrigea, Cardwellia sublimus, Castanospermum australe, five Flindersia species and Musgravea heterophylla were much less promising for VP under the conditions employed.
For a subset of three species, highly significant differences among clone means were demonstrated for two key VP traits (rootability and number of roots per rooted cutting). Differences were also observed in other species and in the propensity of hedged seedlings of all sixteen species to produce coppice shoots.
Rooted cuttings of seven species were included in one or two field trials for preliminary assessment of the potential of these species for deployment as clones. The more promising species for growth as rooted cuttings on at least one site were E. grandis (outstanding), C. odorata, A. cunninghamii and A. robusta. Rooted cuttings of A. aulacocarpa grew moderately well, but apparently less well than seedlings at both sites. Those of A. flammeum and G. fasciculiflora were not promising for growth at either site, nor for survival at one site. Differences between clones in survival and growth were observed in some species.
Based on the results of this preliminary study and other work, prospects for VP, clone selection and deployment as individual clones or clone mixtures using rooted cuttings, seem good for a few of the species. Further work would be required to achieve realisation of the potential of the promising species.