Variable-retention harvesting in Tasmania: regeneration success?

Summary

Society’s changing expectations for forest management and an improved understanding of wet-forest ecology have led to the adoption of variable-retention silviculture in Tasmania’s old-growth wet eucalypt forests. Aggregated retention (ARN) retains patches of forest after harvesting to help maintain biodiversity and ecosystem function at the site level, but these ecological goals must be balanced against silvicultural considerations such as achieving successful regeneration. We sampled 38 ARN coupes that were harvested and regenerated from 2007 to 2010 and 31 paired clear-fell, burn and sow (CBS) coupes. Despite more complex boundary shapes and thus much higher levels of forest edge influence, the development of successful ‘slow burning’ methods combined with the adoption of aerial sowing in all ARN coupes has resulted in early regeneration densities and growth rates that are very comparable with those in clear-felled coupes. The longer-term effects of ARN harvesting on eucalypt productivity require further research, but these early results indicate that the initial silvicultural goals for eucalypt regeneration can be met after ARN harvesting in wet eucalypt forests.

Keywords:

• silvicultural systems
• silviculture
• regeneration
• forest influences
• Tasmania

Acknowledgements

The authors would like to thank all those who helped with many years of field work or who otherwise contributed to the success of this research. Comments from two anonymous reviewers considerably improved the manuscript. Other support was provided by the CRC for Forestry and the University of Tasmania.

Additional information

Funding

Funding for this study came from the Tasmanian Community Forestry Agreement.