3. Changes of plant biomass in the DDF Table 1 shows plant biomass in the DDF separated into stem, branch, leaf and root. Average biomass amount was increased from 83.74±12.35 Mg ha-1 in 2010 to 90.65± 11.36 Mg ha-1 in 2015; a net. increase of 6.91 Mg ha-1 (8.3%). The annual increment was Table 1 Amount of plant biomass in 12 plots (4 stands) in the DDF between 2010 and 2015 Plot Dominant Plant biomass (Mg ha-1) No. Tree Stem Branch Leaf Root Total 2010 2015 2010 2015 2010 2015 2010 2015 2010 2015 Net 1 Hiang 58.53 62.8 16.43 18.59 2.39 2.41 12.81 13.36 90.16 95.96 5.80 2 Hiang 49.08 49.56 14.98 15.26 1.70 1.69 9.95 9.97 75.71 75.06 -0.65 3 Hiang 57.62 61.00 16.55 17.86 2.23 2.29 12.35 12.93 88.75 93.03 4.28 4 Hiang 53.98 58.79 14.57 16.50 2.29 2.33 11.88 12.54 82.72 88.44 5.72 5 Hiang 64.05 68.36 18.18 20.14 2.49 2.47 13.62 14.10 98.35 103.26 4.91 6 Hiang 63.21 68.20 18.44 20.60 2.35 2.36 13.23 13.90 97.23 103.58 6.35 7 Hiang 59.51 64.30 18.38 20.77 1.98 1.92 12.05 12.47 91.93 97.99 6.06 8 Hiang 62.88 69.21 17.30 19.34 2.62 2.80 13.77 14.96 96.57 104.69 8.12 Mean 58.61 62.78 16.85 18.63 2.26 2.28 12.46 13.03 90.18 95.25 5.07 S.D. 5.11 6.52 1.5 1.99 0.29 0.34 1.23 1.5 7.81 9.93 2.12 9 Rang 44.8 58.33 13.94 19.71 1.45 1.59 8.90 10.96 69.09 89.22 20.13 10 Rang 39.07 47.29 10.87 14.24 1.57 1.64 8.39 9.61 59.91 71.44 11.53 Mean 41.93 52.81 12.41 16.98 1.51 1.61 8.65 10.29 64.50 80.33 15.83 11 Pluang 47.03 51.13 13.79 15.66 1.70 1.70 9.67 10.20 72.19 77.22 5.03 12 Teng 53.6 58.36 15.07 16.82 2.13 0.73 11.43 12.17 82.23 87.86 5.63 Mean 54.45 59.78 15.71 17.96 2.08 1.99 11.55 12.26 83.74 90.65 6.91 S.D. 8.02 7.42 2.27 2.23 0.39 0.56 1.85 1.74 12.35 11.36 -0.99 4. Changes of water amount stored in plant biomass Average amount of water in plant biomass in the DDF increased from 34.20±4.94 m3 ha-1 in 2010 to 38.70±5.27 m3 ha-1 in 2015; a net. increase of 4.69 m3 ha-1. The annual increment of water storage was calculated at 0.94 m3 ha-1 yr-1 (2.74%) (Table 2). The average water amount stored the Hiang stand was 36.50 m3 ha-1 in 2010 and 40.99 m3 ha-1 in 2015; net. increase of 4.48 m3 ha-1 (0.90 m3 ha-1 yr-1). As for the Rang stand, the value was 26.13 m3 ha-1 in 2010 and 32.44 m3 ha-1 in 2015; net. increase of 6.31 m3 ha-1 (1.26 m3 ha-1 yr-1). The Pluang stand had the value of 29.50 m3 ha-1 in 2010 and 33.52 m3 ha-1 in 2015; net calculated to be 1.38 Mg ha-1; only 1.6% increase. The net. increases of plant biomass in the Hiang, Rang, Pluang and Teng stands were 5.07 Mg ha-1 (1.02 Mg ha-1 yr-1), 15.81 Mg ha-1 (3.16 Mg ha-1 yr-1), 5.03 Mg ha-1 (1.01 Mg ha-1 yr-1) and 5.63 Mg ha-1 (1.12 Mg ha-1 yr-1), respectively. increase of 4.02 m3 ha-1 (0.80 m3 ha-1 yr-1), whereas the Teng stand had the value of 34.41 m3 ha-1 in 2010, and 38.13 m3 ha-1 in 2015; net increase of 3.72 m3 ha-1 (0.74 m3 ha-1 yr-1). A major forest disturbance in Thailand was selective cutting of big and medium trees in the past, this resulted in mainly secondary forest. In National Parks, the forest is strongly protected from tree cutting, elsewhere such protection varies with forest stands (Oliver and Larson, 1996; Waring and Running, 1998). Since the DDF covers a xeric site where the soil is poor and usually disturbed by forest fire, natural regeneration is normally slow particularly seed germination. However, 26 Proceedings of the International Conference on Climate Change, Biodiversity and Ecosystem Services for the Sustainable Development Goals (SDGs): Policy and Practice 27-29 June 2016, Cha-am, Phetchaburi, Thailand
Proceedings of International Conference on Climate Change, Biodiversity and Ecosystem Services for the Sustainable Development Goals : Policy and Practice 27-29 June 2016 at the Sirindhorn International Environmental Park, Cha-am, Phetchaburi, Thailand
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