Carbon and nutrient storages in an upper montane forest at Mt. Inthanon summit, northern Thailand

Investigation on carbon and nutrient storages in the ecosystem of an upper montane forest (UMF) was carried out at Mt. Inthanon, the highest mountain in Thailand. A method of plant community analysis was used for studying vegetation structure and plant species diversity. Fifty sampling plots, 40×40 m2 in size, were arranged using a stratified random technique over the forest from about 2,000 m to 2,565 m above mean sea level. Forest biomass of 47 woody species was calculated using allometric equations of Tsutsumi et al. (1983). The total plant biomass was estimated to be 703.8 Mg ha-1. The total amounts of stored carbon, nitrogen, phosphorus, potassium, calcium and magnesium in the biomass were calculated to be 347.91 Mg ha-1, 4038.79 kg ha-1, 459.07 kg ha-1, 2001.37 kg ha-1, 7112.48 kg ha-1 and 1515.47 kg ha-1, respectively. Quercus eumorpha had the highest amount of nutrient storage, followed by Syzygium angkae, Shima wallichii, Litsea martabarnica, Lindera caudata, etc. The annual amounts of recycling through litterfall for these nutrients were in the following order: 3425.31 kg ha-1, 121.21 kg ha-1, 5.54 kg ha-1, 33.04 kg ha-1, 303.06 kg ha-1 and 10.41 kg ha-1. Their total amounts in organic layers were measured to be 19.46 Mg ha-1, 594.30 kg ha-1, 36.51 kg ha-1, 101.78 kg ha-1, 488.59 kg ha-1 and 56.64 kg ha-1, respectively. The total amounts of carbon, nitrogen, extractable P, extractable K, extractable Ca and extractable Mg in a one-meter soil profile were evaluated to be as follow: 262.47 Mg ha-1, 10209.41 kg ha-1, 87.71 kg ha-1, 227.24 kg ha-1, 270.76 kg ha-1 and 64.69 kg ha-1, respectively. Thus, the total ecosystem storages of carbon and nitrogen were in the following order: 629.84 Mg ha-1 and 14842.50 kg ha-1. The storages of the two nutrients were high in this forest as it is an abundant forest that has not had forest fire and low levels of soil erosion.