Use variable retention management during forestry operations

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

45%
Certainty

20%
Harms

25%

Calculating overall effectiveness category

Background information and definitions

Variable retention timber management is a silvicutural technique designed to retain habitat features important for wildlife e.g. large trees, snags and woody debris. This method of harvesting does not seek to maximize timber production.

Key messages

A replicated, controlled study from the USA found that nine bird species occurred at higher densities in stands under variable retention management, compared to control stands. Five were found at lower densities.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, controlled study in the summers of 2003-2004 in bottomland hardwood forest on Tensas River National Wildlife Refuge, Louisiana, USA (Twedt & Somershoe 2009), found that densities of nine species of birds (six of conservation concern) were higher in stands under variable-retention timber harvests, compared to control (untreated) stands. Densities of five species were greater in untreated stands. Conservation concern scores and detection rates of 30 species, suggest that the mosaic of treated stands afforded greater community-wide bird conservation value than untreated stands. Bird densities were estimated (distance sampling) within forest subject to variable-retention harvests within a 13-year chronosequence (i.e. a set of forested sites with similar attributes but of different ages), and untreated stands.
Study and other actions tested
Referenced paper
Twedt D.J. & Somershoe S.G. (2009) Bird response to prescribed silvicultural treatments in bottomland hardwood forests. Journal of Wildlife Management, 73, 1140-1150.

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bird Conservation

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