Modeling of evapotranspiration changes with forest management practices: A genealogical review

There exist very few reviews of models that predict changes in evapotranspiration with forest management (e.g., clearcutting and thinning). This omission has potentially prevented forest hydrologists from effectively identifying critical research topics and collaborating with policymakers, practitioners, and researchers in related fields to assist policymaking. To remedy this omission, the current study elaborates why models were needed in the first place and how models were developed historically. Models were developed to overcome limitations of traditional meta-analyses of measurement studies (i.e., inability to explain between-site variations in evapotranspiration changes with forest management) that had been recognized since the 1960s. With the improvement of the understandings about evapotranspiration processes, forest hydrologists proposed models that could predict changes in evapotranspiration with forest management around 1990. Among the models proposed around 1990, models for large scales were widely used for practical purposes (e.g., assessing the impact of large-scale deforestation on the continental and global water cycle). However, models for small scales were not widely used for assessing the impacts of forest management on water resources and other practical purposes. One major reason for this was that models for small scales proposed around 1990 were primarily designed as research tools. To improve practical applicability, forest hydrologists then started developing simple, practical models for small scales that focused on applications to a particular area, species, and purpose around 2000. Considering the necessity of human society to adapt to emerging environmental challenges within a limited time frame, we conclude that the primary role of forest hydrologists in this era is to quickly detect emerging environmental challenges and then develop practical models for connecting different stakeholders for collective decision-making. This paper also suggests that the use of practical models can be a starting point to rearticulate the role of forest hydrologists in policymaking.