Providing evidence to improve practice

Action: Adopt certification

Key messages

  • One replicated, site comparison study in Ethiopia found that the risk of deforestation was lower in certified than uncertified forests. One controlled, before-and-after trial in Gabon found that when logging intensity was taken into account although tree damage did not differ, changes in above-ground biomass were smaller in certified than in uncertified forests.


Supporting evidence from individual studies


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.


A replicated, site comparison study in 2010 in highland rainforests in the Oromiya region, Ethiopia (Takahashi & Todo 2013) found that forests producing wild, shade-grown coffee Coffea arabica with a certification had a lower risk of deforestation than forests where coffee was grown without certification. Forests under a coffee certification program had a lower probability of deforestation (2.8%) than similar areas where no forest coffee was produced (4.5%). However, where coffee was grown without certification, the probability of deforestation (11.8%) did not differ from similar areas where no coffee was grown (12.4%). The study was conducted in two forests that were certified in 2007 and two forests that were considered uncertified during the study as they only received certification in 2009, just before the measurements of forest cover in 2010. Probability of deforestation was estimated using satellite images (Landsat, resolution 30 m) from 2005 and 2010.


Referenced papers

Please cite as:

Agra, H., Schowanek, S., Carmel, Y., Smith, R.K. & Ne’eman, G. (2017) Forest Conservation. Pages 285-328 in:W.J. Sutherland, L.V. Dicks, N. Ockendon & R.K. Smith (eds) What Works in Conservation 2017. Open Book Publishers, Cambridge, UK.