1) The study estimated the carbon stock of a protected tropical forest in Cebu, Philippines across three carbon pools: vegetation, soil, and litterfall. 2) A total of 20 plots were sampled across homogeneous and heterogeneous areas of the forest, which is dominated by Mahogany and Teak trees. 3) Results found an average of 653.9 tons of carbon stored per hectare in the forest's biomass. The homogeneous areas stored more carbon than heterogeneous areas. 4) Soil organic carbon and litterfall carbon were also quantified monthly from April to August 2010. 5) In total, the forest stores a significant amount of carbon across its three pools, helping to offset fossil fuel emissions

1. Estimating Carbon Stock of a Protected Tropical Forest in Cebu, Central Philippines Edgar E. Borga Jr., Ramon Earl L. Labrada & NerizaArche MS

2. Introduction Climate Change Phenomenon Atmospheric CO2increase Tropical Forests Sequester more carbon (Brown et al. 1997) Image Source: http://www.treehugger.com/

3. Introduction Cebu is heavily deforested Reforestation Programs Most Common Species Swieteniamacrophylla (Mahogany) Tectona grandis(Teak) No databank on carbon stock (DENR)

4. Objectives and Limitations Objectives To measure stored carbon in the forest in vegetation, soil and litter carbon pools Limitations No remote sensing Maximum timeframe No atmospheric carbon flux and microbial activity assessment Non parametric analysis was made on data which did not meet assumptions for parametric analysis.

5. Methodology

6. Study Site Buhisan Watershed Forest Reserve BarangayToong (52.4 ha or 8.6% of BWFR) Rugged terrain and irregular elevation ranging from 100m to 400m ASL Tectona grandis(Teak) and Swieteniamacrophylla (Mahogany) Soil is limestone with limestone rock covered with clay to loam soil Divided between homogenous and heterogeneous areas

8. Sampling First week of April Twenty 20x20 m plots (Ramachandran et al. 2007) 10 homogenous 10 heterogeneous Randomly Followed traversable roads and trails For each 15 minutes walking, a site was randomly chosen When required number of heterogeneous sites were obtained – only homogenous sites were further sampled

9. Vegetation Analysis Survey 20, 20m x 20m subplots Diameter at breast height (DBH) Density, Dominance & Importance value

10. Vegetation/Biomass Carbon Estimation DBH (<5cm) Above Ground (Brown, 1997) Y (AGB) = 42.69-12.800(D)+1.242(D²) Below Ground (Cairns et al. 1997) Y (BGB) = exp(-1.0850+0.9256(In Y (AGB)) 50% is carbon (Brown et al 1995) Image source: http://harvardforest.fas.harvard.edu/

11. Litterfall Carbon Litter plot 1x1m (Gosz, 1980) Monthly Collection Leaves, wood, fruit and flowers % C via Gravimetric method of dry combustion (Eaton and Lawrence, 2008 and Chan, 1982)

12. Soil Organic Carbon Estimation 0-30 cm depth Bulk Density Core Method Monthly Collection %SOC Walkey & Black's Wet Oxidation Method (Mingorance et al. 2007) Monthly % SOC x Bulk density

13. Statistical Analysis SOC, Leaf carbon litter, biomass carbon, and overall forest carbon ANOVA Post hoc of Tukey’s HSD (monthly) Wood, fruit and flower litter carbon Mann–Whitney U Test

14. Results and Discussion

15. Vegetation Analysis Overall 17 species of trees (Table 1) Barangay Toong is a heavily reforested area. Mostly are occupied by Tectona grandis and Swieteniamacrophylla. Table 1. Density, dominance, importance values, DBH, of majortree species in heterogeneous areas of Barangay Toong. (Mean ± SE)

16. Biomass Carbon Average: 653.9 t C per hectare Homogenous area is considerably higher Figure 4. Above and Below Ground Biomass Carbon (Mean+SE) of the study area

17. Litterfall Carbon Figure 7 Litterfall in study site, for leaves, wood, and fruits/flowers in homogenous and heterogeneous areas(±SE) from April to August 2010.. Figure 5. Climatograph of PAG-ASA from April to August 2010, Mactan Island, Cebu

18. Soil Organic Carbon Figure 8. Monthly average SOC(+SD) of Buhisan Watershed Forest Resreve in barangayToong from April to August 2010

19. Overall Carbon Stock in 3 pools * Significant Between 3 Pools (Biomass, Soil, and Soil)

20. Stored Carbon in Relation to Fossil Fuels Gasoline: 640 g C / Liter Diesel: 734 g C / Liter (Source: U. S. Environmental Protection Agency) Forest age of 60 years Density of 1 tree in every 19.75 sq m

21. Conclusions and Recommendations No significant difference between two area types within the study period for carbon storage Longer temporal scale, as well as better means of measuring carbon stored. Buhisan Watershed Forest Reserve Protected against anthropogenic disturbance More efforts should be made to convert idle lands to secondary forests

22. References Brown, S. 1997. Estimating biomass and biomass change of tropical forest: A primer. Rome: Food and Agriculture Association of the United Nations, FAO. Chan, Y.H. 1982. Storage and release of organic carbon in peninsular Malaysia. IntJournEnvi Stud. 18(3-4):211-222. DENR Region 7. 2003. Management Plan: Central Cebu Protected Landscape. Eaton, J.M., Lawrence, D. 2008. Loss of carbon sequestration potential after several decades of shifting cultivation in the Southern Yucatán. Forest Ecol. Manag 258:949-58. Gosz, J.R. 1980. Biomass distribution and production budget for a nonaggrading forest ecosystem. Ecology 61:507–14. Mingorance, M.D., Barahona, E., Fernández-Gálvez, J. 2007. Guidelines for improving organic carbon recovery by the wet oxidation method. Chemosphere 68:409–13.

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