Is continuous-cover silviculture, as practised in Bavaria, suitable for use in wet eucalypt forests in Tasmania, Australia?

Summary

Appropriate silviculture, based on natural forest dynamics and ecological attributes of tree species, is fundamental to the sustainable management of native (natural and semi-natural) forests for wood production. Continuous-cover silviculture works well in shade-tolerant spruce–fir–beech forests of Central Europe (in this paper, we use the German state of Bavaria as a typical example) and can be regarded as ‘close-to-nature’, particularly where there is a focus on maintaining some old-growth elements for long-term retention. Continuous-cover silviculture, however, cannot be regarded as ‘close-to-nature’ for Australian wet eucalypt forests, which are dominated by shade-intolerant eucalypts that are dependent on intensive disturbance, usually associated with fires, for their regeneration.

While the prevailing technique of clearfelling, burning and sowing of eucalypt seed has some affinities with natural regeneration processes stimulated by bushfires, it differs substantially from natural disturbances in that it is more uniform than bushfires and removes most ‘legacy’ structures such as live and dead trees, which are important to maintain some continuity of ecosystem functioning between forest generations. Variable retention silviculture, which retains mature stand elements for incorporation in the new stand, better approximates ‘close-to-nature’ silviculture for wet eucalypt forests. Silvicultural trials and recent operational experience show that variable retention can be applied successfully in wet eucalypt forests in some situations.

Although Tasmania has much higher levels of formal ecological reserves than Bavaria (49% compared to just 3%), its use of native forests, particularly wet eucalypt forests, for wood production struggles for acceptance by the general public. We suggest that high levels of social acceptance of forestry in Bavaria, and low levels in Tasmania, cannot be explained purely by ecological and silvicultural differences of the forest types. Other influential factors in Bavaria compared with Tasmania include higher levels of private forest ownership, practical forest knowledge, domestic processing, established forest road networks and profitability.

Keywords:

• silviculture
• regeneration
• ecology
• forest management
• forestry practices
• forest ownership
• public opinion
• eucalypts
• Bavaria
• Tasmania

Acknowledgements

John Hickey gratefully acknowledges the Gottstein Trust for providing a grant to study silviculture, certification and social acceptability in Central Europe in 2011, and staff of Bayerische Staatsforsten (particularly Stefan Breit, Peter Graser and Dr Saul Walter) for sharing their knowledge of continuous-cover forestry.

Notes

1. Wet eucalypt forests are characterised by a tall (>34 m) open forest canopy over a dense secondary layer of small trees and tall shrubs.

2. This definition is narrower than that applied in many other jurisdictions, where openings of more than four tree lengths are used to define clearfells (e.g. Keenan and Kimmins 1993). In Tasmania, the minimum size of a clearfell is defined as 4–6 tree lengths (Forest Practices Board 2000).