There is a distinct dry season lasting for 4-5 months in Thailand. Although the
annual precipitation and its seasonal pattern are similar, various forest types, called
mixed deciduous forest (MDF), dry dipterocarp forest or drought deciduous forests
(DDF), and dry evergreen forest (DEF), are found. MDF and DDF are mainly
consisted of drought-deciduous trees, whereas DEF are mainly consisted of evergreen
trees. DDF has thin and poor-nutrients soil and many dipterocarp trees are
predominant. In contrast, MDF has rich-nutrients soil and dipterocarp trees are rare.
Therefore, forest types are due to soil properties, and the forest function is dependent
on species structure (Rundel and Boonpragob 1995; Ishida et al. 2006).
Canopy leaves with low mass-based photosynthetic rates and leaf nitrogen (N)
concentrations and high leaf mass per area (LMA) generally have a long leaf lifespan
(Reich et al. 1999; Wright et al. 2004; Ishida 2008), contributing to a slow N cycling
within forests. Leaf ecophysiological characteristics are thus major determinants of
forest functions, such as carbon flux of forest canopies and nutrients cyclings within
forests. Recently, meta-analysis, using a huge number of data in various areas, has