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

  • Published source details Medjibe V. P., Putz F.E. & Romero C. (2013) Certified and uncertified logging concessions compared in Gabon: changes in stand structure, tree species, and biomass. Environmental Management, 51, 524-540.


This study is summarised as evidence for the following.

Action Category

Adopt certification

Action Link
Forest Conservation
  1. Adopt certification

    A controlled, before-and-after study in 2010–2011 in two mixed lowland tropical forests in Ogooué-Ivindo, Gabon (Medjibe, Putz & Romero 2013) found that once logging intensity was taken into account a certified logged forest had similar tree damage but a smaller change in above-ground biomass than a more intensively logged uncertified forest. The amount of tree biomass damaged was lower in the certified forest than in the uncertified forest (certified: 18.7; uncertified: 33.7 Mg/ha). However, there was no difference in damage between the two forests when the higher logging intensity in the conventional forest was taken into account (certified: 3.3; uncertified: 2.9 Mg/m3). The change in above-ground biomass was smaller in the certified forest (certified: 7%; uncertified: 13%), even when corrected for logging intensity. The tree species composition after logging did not change in either forest (difference in Simpson’s Index before and after harvest: certified 0.96; uncertified 0.41). The logging intensity in the certified forest was 5.7 m3/ha and 11.4 m3/ha in the uncertified forest. Twenty plots in the certified forest and 12 in the uncertified forest were established (each 200 × 50 m). Measurements were taken within each plot 2-6 months before and 2-3 months after logging for all trees with a diameter breast height > 10 cm.

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 20

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust