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Abstract

Blackwood (Acacia melanoxylon R.Br.) is a high-quality appearance-grade
timber species native to eastern Australia. Wide variation in its survival, growth and form,
together with issues related to site selection and intensive silvicultural management, limit
progress in its domestication and commercial development. To determine the effect of
genetics on these traits, five blackwood progeny trials in northern Tasmania, Australia,
aged between 15 and 19 years were assessed. All trials contained a variety
of open-pollinated, single-tree, family collections from Tasmania, with one trial containing
a selection of provenances from mainland Australia. Significant genetic variation in
survival, growth and form were found. This variation was partly explained by broad scale
adaptive differences across the wide geographic distribution of blackwood. Blackwood
from the tropical northern range of the species had poor survival in cool temperate Tasmania.
Significant differences in survival between Tasmanian seedlots were also observed.
Among the Tasmanian seedlots, those from low altitudes grew better than those from high
altitudes, while those from the north-east of Tasmania had significantly better growth rates
than seedlots from the south-east. Seedlots from the north-west seed zone had intermediate
growth rates. Significant genetic differences in the proportion of trees with single stems,
and the number of large branches in the lower stem were found between Tasmanian
seedlots. Early-age seedlot height was significantly positively correlated with mid-age
diameter. Stem form was improved under nurse crops, but even open-grown blackwood
had low percentages of trees of excellent form. These results indicate that at the broad
scale, climatic matching of seed source with planting site is clearly important, however,within Tasmania there was no evidence that seedlots collected from the same region as the
trials outperformed those from other regions.

Item Type:	Article
Authors/Creators:	Bradbury, GJ and Beadle, CL and Potts, BM
Keywords:	Australian blackwood ; Provenance ; Tasmania ; Heritability ; Adaptation
Journal or Publication Title:	New Forests
ISSN:	0169-4286
DOI / ID Number:	https://doi.org/10.1007/s11056-009-9160-9
Additional Information:	The original publication is available at www.springerlink.com
Item Statistics:	View statistics for this item

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