Deadwood in logged-over Dipterocarp forests of Borneo

Deadwood is an important stock of carbon in logged-over Dipterocarp forests but still remains poorly studied. Here we present the study of deadwood in logged-over Dipterocarp forests using two common approaches: plot-based approach and line-intersect-based approach. We conducted our research in three sites which are forest logged in 2003, 2007, and 2010 within Hutansanggam Labanan Lestari (HLL) forest, a certified forest concessionaire in Indonesia. We established 1,500 m of transect line (broken down in 50 m section) for each site. As a reference, we established 47 10 m x 10 m subplot for three sites. All fallen deadwood with diameter > 10 cm were recorded. Our results shows that the mass of fallen deadwood resulted by line-intersect-based method was much higher in compare to plotbased method. The mass of fallen deadwood in plot-based study (44.563 ± 9.155 Mg/ha) was significantly different with the mass of fallen deadwood in line-intersect-based study (69.587 ± 8.079 Mg/ha). Furthermore, for the variability of deadwood, both methods show consistence results which is the variability in 2003 was lower than that in 2007 and 2010. Based on our data, in order to get coefficient of variation of 10%, we recommend the use of minimum 40 plots of 20 m x 20 m to estimate deadwood in logged-over Dipterocarp forests. (Texte intégral

Tropical forest degradation in the context of climate change: increasing role and research challenges. [K-2215-01]

While developed countries in temperate regions faced their forest transition about 100 years ago or more, “tropical forest rich” nations still largely depend on forest resources or land clearing for their development. Hence, tropical forests are retreating at an alarming rate from advancing cash crops, such as oil palm, soybean, or cattle ranching. Beside tropical deforestation, tropical forest degradation resulting mostly from human-induced causes (e.g. predatory or illegal logging, non-timber forest product extraction, fuel wood extraction) significantly contributes to greenhouse gas emissions and loss of biodiversity. If deforestation is an obvious ecosystem change, forest degradation is more difficult to discern and quantify. Degraded forests have become a major component of today's tropical landscapes, representing up to 50 % of all tropical forests. For example, almost half of standing primary tropical forests, up to 400 million ha, are designated by national forest services for timber production. The portion of tropical forests managed for timber extraction, hereafter referred to as “managed forests”, will therefore play key roles in the trade-off between provision of goods and maintenance of carbon stocks, biodiversity, and other services. However, so far, most of our understanding of tropical forest arise from studies carried out in old-growth undisturbed forests, or secondary forests (i.e. regrowth forests) while the ecology of degraded forests at the regional and continental scale remains poorly studied and their role to mitigate climate change still very poorly known. However, understanding the functions played by degraded forests in providing goods and environmental services in the context of climate change is crucial. We will first discuss the complex concept of forest degradation in the tropics and then define degraded forests. We will show their importance in providing timber while maintaining high levels of biodiversity and carbon stocks. We will further demonstrate that implementation of sustainable forest management can promote long term provision of ecosystem services. Finally, the potential of tropical degraded forests in mitigating climate change will be discussed along with future research challenges on this issue. (Texte intégral

Community assessment of tropical tree biomass:challenges and opportunities for REDD+

BACKGROUND: REDD+ programs rely on accurate forest carbon monitoring. Several REDD+ projects have recently shown that local communities can monitor above ground biomass as well as external professionals, but at lower costs. However, the precision and accuracy of carbon monitoring conducted by local communities have rarely been assessed in the tropics. The aim of this study was to investigate different sources of error in tree biomass measurements conducted by community monitors and determine the effect on biomass estimates. Furthermore, we explored the potential of local ecological knowledge to assess wood density and botanical identification of trees. RESULTS: Community monitors were able to measure tree DBH accurately, but some large errors were found in girth measurements of large and odd-shaped trees. Monitors with experience from the logging industry performed better than monitors without previous experience. Indeed, only experienced monitors were able to discriminate trees with low wood densities. Local ecological knowledge did not allow consistent tree identification across monitors. CONCLUSION: Future REDD+ programmes may benefit from the systematic training of local monitors in tree DBH measurement, with special attention given to large and odd-shaped trees. A better understanding of traditional classification systems and concepts is required for local tree identifications and wood density estimates to become useful in monitoring of biomass and tree diversity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13021-015-0028-3) contains supplementary material, which is available to authorized users