I. INTRODUCTION Changes of plant community in a forest involves species richness, composition, diversity and ecological roles by measuring these parameters during a period of time. It is assumed that either local environment or climate change have influenced these changes. The DDF covers dry sites in northern, northeastern and central Thailand. The forest vegetation has a major role on the hydrologic cycle in a watershed. The rate at which water infiltrates into soil, surface runoff and percolates into water table is affected by density and depth of roots and soil organic matter. Theories of forest hydrologic cycle have been described by Landberg and Gower (1997), Waring and Running (1998), Kimmins (2004) and Chang (2006). Most contents focus on water input and movement such as interception-evaporation by forest canopy, throughfall, stemflow, plant use, transpiration, water flow through vegetation, evaporation from soil, infiltration into soil, drainage and runoff and stream flow. This research aims at monitoring plant species diversity and its role on water storage in plant biomass of a dry dipterocarp forest (DDF) at the HHKRDS Center. The data provides useful information for forest and watershed management. II. MATERIALS AND METHODS 1. Study area The research was conducted in the HHKRDS Center, Chiang Mai province, about 27 km to the north of Chiang Mai city. The Center covers an area of about 1,360 ha with an altitude range between 350 and 591 meters above sea level. 2 2. nPlant community study A method of plant community analysis was used for plant study in 2010 and 2015 using 12 plots, each of size 40 x 40 m2. All tree stems were numbered in sequence, and measured for stem girths at 1.3 m above ground (gbh) and tree heights. Plant data were calculated for frequency, density, importance value index and Shannon-Wiener Index (Krebs, 1985). Forest condition index (FCI) was based on an equation given by Seeloy-ounkeaw et. al. (2014). FCI = Ʃ n.10-4 + n.10-3 + n.10-2 + 123n.10-1 + 1(n) + 2(n) + …… 456Where n1 = number of tree individuals having GBH<25 cm = number of individuals having GBH 25 to <50 cm n3 = number of individuals having GBH 50 to <75 cm n4 = number of individuals having GBH 75 to <100 cm n5 = number of individuals having GBH 100 to < 200 cm n6 = number of individuals having GBH 200 to < 300 cm S W3. Plant biomass estimation Plant biomass was measured using allometric equations Ogino et. al. (1967). = 189 (D2H)0.902 WB = 0.125Ws1.204 R W 1/WL = (11.4/ws0.90) + 0.172 Where WS = stem biomass in kilogram WB = branch biomass in kilogram WL = leaf biomass in kilogram The unit of stem diameter (D) and tree height (H) was in meters. The root biomass was calculated using an equation of Ogawa et. al. (1965). = 0.026 (D2H)0.775 The unit was in kilogram for WR, centimeter for D and meter for H. 24 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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