Forest carbon baseline study in Leyte: Climate-relevant Forest Policy and Piloting of REDD [Final draft report]

Executive Summary

From mid-2011 until the end of 2012, the Department of Environment and Natural Resources (DENR) carried out a forest carbon baseline study in Leyte Island, supported by the Provincial Government of Southern Leyte, the Energy Development Corporation (EDC) and the GIZ project “Climate-relevant Forest Policy and Piloting of REDD”. The forest resources assessment (FRA) covered the REDD+ pilot area in Southern Leyte, the forest areas in Southern Leyte outside of the

REDD+ area and Leyte Province. The FRA applied a two-stage inventory design: forest area assessment by remote sensing as the first stage and field sampling in the forest stratum as the second stage. The forest area has been assessed by the REDD Project through analysis of PALSAR radar data, using the field sampling records and Google Earth images for ground truthing.

For field sampling, 200 clusters of four circular plots each have been randomly distributed over the forest area along a 1 x 1 km coordinate grid. 100 clusters have been recorded within the REDD+ pilot area and 50 clusters each in the remaining parts of Southern Leyte and in Leyte Province. Each plot consisted of two concentric circles with 6 m and 12 m radius, to record tree parameters, deadwood and litter, and to assess biodiversity. In addition, four field clusters have been established in mangrove areas in Southern Leyte, to estimate also the biomass and carbon content of mangrove vegetation.

According to the FRA results, the average bole volume amounts to 180 m3/ha. The average above-ground tree biomass in Leyte Island reaches 255 tons per ha, equal to 127.4 tons of carbon/ha. Forest tree carbon accounted for 96.7% of all forest carbon, deadwood carbon for 1.7%, litter for 1.3% and mangroves for 0.3%. The average tree volume and biomass measured in 2012 were 20% lower than those recorded during the RP-German Forest Resources Inventory (FRI) in 1986/87. The commercial diameter classes of 40 cm and above contained much less timber, only 64% of the volume recorded in 1987. This reflects a severe forest degradation resulting in the loss of 30.3 tons of carbon per ha. 

The biodiversity assessment showed an average of 31.3 vascular plant species within the plot with 6 m radius. The plant biodiversity in open forest was slightly lower than in closed forest, with an average of 26.9 resp. 32.6 species per sample plot. Dipterocarps are still the dominant species, accumulating around 43% of the overall volume. Their share decreased, however, substantially since the FRI. In 1987, dipterocarps accounted for 72% of all tree volume in old growth and 64% in residual forest. This also reflects a severe degradation of the original biodiversity and ecosystem.