The Rimba Raya Biodiversity Reserve REDD Project

Stratification by Peat DistributionThe principal factor controlling carbon content in peat forests isthe depth of the peat, with type of peat layer and bulk density assecondary factors. The majority of peat swamps in Indonesia aredeeper than 1 m, and sometimes more than 15 m in depth(Rieley et al. 1997). Hooijer estimates 42% of the peat land areasin Indonesia are over two meters thick, accounting for most ofthe country’s peat and carbon deposits (Hooijer et al. 2006).The most comprehensive peat assessment to date for Indonesiawas conducted by Wetlands International using both primary andsecondary data sources (Wayunto et al. 2004). A series of mapswere produced that show peat depth and type for each provinceand district. These data show shallow peats distributedthroughout the Rimba Raya Carbon Accounting Area. WetlandsInternational data was ground-­‐truthed by an in situ peat depthassessment conducted by Forest Carbon and OFI.Peat Depth SurveyPeat depth was measured at 100-­‐meter intervals along all surveytransects. Methods and results are briefly described below anddetailed in two Carbon Assessment Survey Reports (Annex 5). Atotal of 16 km of transect were marked and surveyed with peatdepth measured in 159 locations. Average depth of each transectis shown in Figure 13 together with Wetlands peat mapping.Unexpectedly, peat depths were moderately deep acrossall survey transects. 67% of peat depth measurementsexceeded the reach of the peat probe at ca. 5 meters andaverage depth overall was 4.3 meters.Figure 13. Peat map for Rimba Raya and Tanjung Puting NationalPark from Wetlands International with ground surveymeasurements recorded on carbon assessment survey transects.28