Abstract
This paper describes an ecological classification of tropical monsoon forests in northern Thailand and reviews published hydro-meteorological studies conducted at each forest type. As a result of summarizing current status of knowledge, we found that basic hydro-meteorological aspects, i.e. seasonal variation in energy partitioning throughout a year with normal climatological condition, at most of the forest types in the region has been already studied. Also, we found a clear contrast in evapotranspiration in the dry season between forest types. The contrast might be one of notable characteristics of hydro-meteorology in tropical monsoon forests in the region. Inter-annual variations in both rainfall and its seasonal distribution might be significantly large in this region, leading to occasional severe droughts and irregular ecological rhythms of trees. Recent findings from several study sites imply that the variations in rainfall result in phenological and physiological responses of the studied forest ecosystems. These responses in turn may affect the exchanges of energy, water vapour, and carbon between forest ecosystems in the region and the atmosphere. Such effects of temporal variations in rainfall on the tropical monsoon forests have been poorly understood thus far. We, therefore, stress the necessity of further efforts to examine the ecological and hydro-meteorological responses of all tropical monsoon forests to the inter-annual variation in rainfall and its seasonal distribution.
