Dry Dipterocarp Forest on Sandstone of the Huai Hong Khrai Royal Development Study Center, Chiang Mai Province I. Assessment of Plant Species Diversity and Carbon Storage

Abstract

Assessment of plant species diversity and carbon storage in a dry dipterocarp forest (DDF) on sandstone located in the Huai Hong Khrai Royal Development Study (HHKRDS) Center, Chiang Mai province, was carried out in 2010. Twelve plots, each of size 40 × 40 m², were used for the vegetation study using random sampling over forest having an altitude range between 403 m and 564 m above mean sea level. The plant data were obtained by measuring the stem girth over bark at 1.3 m above ground and the height of all trees taller than 1.5 m. The quantitative characteristics of plants, plant biomass, and carbon amounts derived from the carbon contents in the stem, branch, leaf, and root were measured. The DDF was divided into four stands based on. the most dominant tree species: Hiang (Dipterocapus obtusifolius), Pluang (D. tuberculatus), Rang (Shorea siamensis), and Teng (S. obtusa), respectively, and most area was covered by the Hiang stand. There were 60 species (50 genera, 31 families) with an average density at 3,865 ± 1,669 trees ha^-1 in the four stands. The average amount of plant biomass was calculated to be 83.74 ± 12.35. Mg ha^-1, divided into stem, branch, leaf, and root portions with amounts of 54.45 ± 8.02 Mg ha^-1, 15.71 ± 2.27 Mg ha^-1, 2.08 ± 0.39 Mg ha^-1, and 11.55 ± 1.85 Mg ha^-1, respectively. The carbon amount in biomass was estimated to be 41.59 ± 6.26 Mg ha^-1 partitioned into stem, branch, leaf, and root components of 27.16 ± 4.0 Mg ha^-1 (65.30%), 7.75 ± 1.18 Mg ha^-1 (18.60%), 1.02 ± 0.20 Mg ha^-1 (2.50%), and 5.65 ± 0.97 (13.6%) Mg ha^-1, respectively. The Hiang stand had the highest carbon storage. It was considered that this forest still has a low carbon amount stored in plant biomass because it had been a degraded forest before the establishment of the HHKDS Center in 1984.