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Response of blackwood (Acacia melanoxylon) regeneration to silvicultural removal of competition in regrowth eucalypt forests of north-west Tasmania, Australia

Citation

Jennings, SM and Wilkinson, GR and Unwin, GL, Response of blackwood (Acacia melanoxylon) regeneration to silvicultural removal of competition in regrowth eucalypt forests of north-west Tasmania, Australia, Forest Ecology and Management, 177, (1) pp. 75-83. ISSN 0378-1127 (2003) [Refereed Article]

DOI: doi:10.1016/S0378-1127(02)00326-2

Abstract

Saplings of blackwood (Acacia melanoxylon) responded positively to release from competing young Eucalyptus obliqua in native forests of north-west Tasmania. In the treated area, 6 years after establishment of the regrowth forest on a cleared and burned seedbed, the young emergent eucalypts were culled by stem injection of herbicide. The dense sub-canopy (principally Pomaderris apetala) was also removed in two gap treatments (3.6 and 7.2 m diameter); each treatment applied to 27 single tree plots. During the 6 years following silvicultural treatment, periodic annual increment (PAI) of blackwood stem diameter increased from 0.8 cm per year in the untreated area to 1.4 cm per year where eucalypts (only) had been removed. The additional removal of the sub-canopy increased blackwood PAl (diameter) to 1.6 cm per year in the small gaps and 2.1 cm per year in the larger gaps. These are statistically significant increases of 75, 100 and 160%, respectively. However, the larger sub-canopy gaps produced heavier, broader blackwood crowns, increased branch size and retention and reduced the length of branch-free bole. Maximum blackwood diameter and volume gains were therefore achieved at the expense of tree form and future log quality. In contrast, the removal of competing eucalypts (only) produced a smaller stem diameter response, but the remaining dense sub-canopy maintained excellent stem form and clear bole. © 2002 Elsevier Science B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Forestry Sciences
Research Field:Forestry Management and Environment
Objective Division:Plant Production and Plant Primary Products
Objective Group:Forestry
Objective Field:Native Forests
Author:Unwin, GL (Mr Greg Unwin)
ID Code:28408
Year Published:2003
Web of Science® Times Cited:10
Deposited By:Geography and Environmental Studies
Deposited On:2003-08-01
Last Modified:2004-03-31
Downloads:0

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