Relationships between forest properties and evapotranspiration rates

We identified problems in clarifying relationships between forest properties (e.g., broad-leaved/coniferous, canopy height, etc.) and evapotranspiration rates, and then proposed a plan to solve the problems. Furthermore, we showed how much the plan has accomplished. The problems were such that the generality of observation results is unclear. That is, it is unclear whether observation results at a site are applicable to other sites. We pointed out that developing a model that expresses evapotranspiration rates as functions of meteorological conditions and site parameters is useful for examining the generality of observation results. Then, we developed a model and described the model structure. For using the model, four examinations are required: 1) dry-canopy evaporation rates in a growing season, 2) wet-canopy evaporation rates in a growing season, 3) seasonal pattern of dry-canopy evaporation rates, and 4) seasonal pattern of wet-canopy evaporation rates. We have completed the examination of dry-canopy evaporation rates in a growing season using the Priestley-Taylor coefficient (α), and obtained the following two conclusions. First, α values for broad-leaved forests tend to be higher than those for coniferous forests. Second, α values for coniferous forests relate to canopy height.