The evidence-base for retention
approaches in forestry
Lena Gustafsson, SLU, Department of Ecology,
Uppsala, Sweden
Uppsala Sweden
Outline
• What are retention
approaches in forestry?
• How does biodiversity
respond to retention
approaches?
• Are retention
approaches a good
conservation tool?
Retention approaches in forestry –
integration of conservation into production forestry
Retention approaches
• Focus on what is left, not
what is taken out
• Aim: promote
biodiversity, sustain
ecological functions
• Mostly discussed as a
modification to
clearcutting
• Relevant for all forestry
systems
• Started about 25 years
ago
Ecological basis: some habitats are
especially important to biodiversity
Application of retention approaches
British Columbia, Canada
Sweden
Western Australia
Washington state, USA
Conservation or restoration –
depends on landscape
1994
2014
Two main functions
Lifeboating of forest species
Promotion of open-habitat species
Are retention approaches really
good for biodiversity?
A meta-analysis of studies in
temperate and boreal regions
Meta-analysis
• ”Analysis of
analyses”
• 78 papers
• Species number,
abundance, several
taxonomic groups
• 30% average
retention level
• Sweden: 8% as
average
> 6,000 papers
> 2,000 papers
~ 500 papers
78 papers
Clearcut
Harvested area with
retained trees
Forest species
Harvested area with
retained trees
Forest
Open-habitat species
Many studies on biodiversity and
retention approaches
Lindenmayer et al. 2012 Conservation Letters
Several large experiments
Gustafsson et al. 2012 BioScience
Forest species
Results
FOREST SPECIES
Open-habitat species
OPEN-HABITAT SPECIES
Fedrowitz et al. 2014 Journal of Applied Ecology
Results
• Taxonomic groups
showed largely similar
responses
• Response of forest
species increased with
retention level
• Old forest was better
for forest species than
logged areas with
retention
Fedrowitz et al. 2014 Journal of Applied Ecology
Conclusions
• Biodiversity responses to
retention approaches are
overall positive
• The evidence-base seems
sound
• Thus, this adjustment to
logging can be
encouraged
• But:
– some forest species need
larger set-aside areas
Fedrowitz et al. 2014 Journal of Applied Ecology
Tack