Certified and uncertified logging concessions compared in Gabon: changes in stand structure, tree species, and biomass

dc.contributor.authorMedjibe, V.P.
dc.contributor.authorRomero, C.
dc.titleCertified and uncertified logging concessions compared in Gabon: changes in stand structure, tree species, and biomassen
dcterms.abstractForest management certification is assumed to promote sustainable forest management, but there is little field-based evidence to support this claim. To help fill this gap, we compared a Forest Stewardship Council (FSC)-certified with an adjacent uncertified, conventionally logged concession (CL) in Gabon on the basis of logging damage, above-ground biomass (AGB), and tree species diversity and composition. Before logging, we marked, mapped, and measured all trees >10 cm dbh in 20 and twelve 1-ha permanent plots in the FSC and CL areas, respectively. Soil and tree damage due to felling, skidding, and road-related activities was then assessed 2-3 months after the 508 ha FSC study area and the 200 ha CL study area were selectively logged at respective intensities of 5.7 m3/ha (0.39 trees/ha) and 11.4 m3/ha (0.76 trees/ha). For each tree felled, averages of 9.1 and 20.9 other trees were damaged in the FSC and CL plots, respectively; when expressed as the impacts per timber volume extracted, the values did not differ between the two treatments. Skid trails covered 2.9 % more of the CL surface, but skid trail length per unit timber volume extracted was not greater. Logging roads were wider in the CL than FSC site and disturbed 4.7 % more of the surface. Overall, logging caused declines in AGB of 7.1 and 13.4 % at the FSC and CL sites, respectively. Changes in tree species composition were small but greater for the CL site. Based on these findings and in light of the pseudo replicated study design with less-than perfect counterfactual, we cautiously conclude that certification yields environmental benefits even after accounting for differences in logging intensities. Abstract obtained with permission, to access full article click here:
dcterms.accessRightsLimited access
dcterms.bibliographicCitationMedjibe, V. P., F. E. Putz, and C. Romero, 'Certified and Uncertified Logging Concessions Compared in Gabon: Changes in Stand Structure, Tree Species, and Biomass', Environmental Management, vol. 51, 2013, pp. 524-540.en
dcterms.typeJournal Article
fsc.evidenceCategoryFSC impact-related
fsc.focus.forestTypeNatural Forest
fsc.issue.economicForest Management
fsc.issue.environmentalForest disturbance, forest degradation
fsc.subjectLandscape approaches
fsc.subjectForest disturbance
fsc.subjectForest degradation
fsc.subjectCarbon stock
fsc.subjectCarbon dioxide emissions
fsc.subjectPlant biodiversity
fsc.topic.environmentalPlant biodiversity
is.availability.fullTextFull text available
is.contributor.memberForest Stewardship Council
is.coverage.placeMilole ́, Province of Ogooue ́-Ivindo
is.coverage.regionWestern Africa
is.evaluation.collectionField measurement
is.evaluation.comparisonTreatment vs Control
is.evaluation.dataSourceIndependent researcher data
is.evaluation.findingsThe authors found that for each tree felled, the certified operation caused damage to 9 trees while the conventional logging caused damage to more than 20 trees. Tree damage was however similar when expressed per timber volume extracted. Skid trails occupied 2.9% more of the forest surface in the conventionally-logged forests than in the certified one. However, skid trail length per unit timber volume was similar. The authors suggest that skid trails width, planning and supervision of staff allowed to reduce collateral damages. Also, the authors note that "compared to roads in the FSC concession, roads in the CL concession were wider, longer, and caused more damage whether expressed per unit area, per number of trees harvested, or per harvested timber volumes."
is.evaluation.findingsFSC certification allowed to reduce the decline of above-ground biomass from 13.4% in conventionally-logged operations to 7.1%. Particularly, biomass of protected trees was twice as high in the FSC-certified concession than in the conventional one, and the decrease in biomass of those trees reached 2.7% and 4.1% in FSC-certified and conventional concessions, respectively. The authors conclude that carbon dioxide emissions are likely to be lower and biomass recovery faster in the FSC-certified concession because of fewer deleterious impacts.
is.evaluation.findingsThe authors did not find differences in tree species composition between certified and conventional logging. They concluded that this lack of differences was due to logging intensities being particularly low under both management regimes.
is.evaluation.scopeThis study explores impacts of felling, skidding and road-related activities on soil and tree damages, above-ground biomass and tree species diversity in Gabon. The authors conducted a comparison between a FSC-certified concession with a conventionally-logged one, and sampled soil and tree states before and after logging occurred.
is.evaluation.significanceStatistically significant
is.evidenceSubTypeEmpirical study - with matched control, data collected post-intervention
is.evidenceTypeEmpirical study
is.focus.productsForestry products
is.focus.sdgSDG 15 - Life on Land
is.focus.sustainIssueForests and other ecosystems
is.focus.sustainIssuePlant and wildlife conservation
is.focus.sustainLensLandscape approaches
is.focus.systemElementMandE outcomes and impacts
is.focus.systemElementMandE performance monitoring
is.identifier.schemeNameForest Stewardship Council
is.identifier.schemeTypeVoluntary Sustainability Standards
is.item.reviewStatusPeer reviewed
is.journalNameEnvironmental Management