Analyzing latent heat fluxes of coniferous forests with fuzzy logic

Fuzzy logic (FL) was applied to simulate latent heat fluxes of six conifero us forests. The goal was to test the application possibilities of fuzzy log ic and to evaluate the information that could be derived from it. The data set consisted of five forests of the Euroflux project and a set of the Doug las fir Speulderbos, 1 year before and 1 year after a thinning. A set of mo dels was compared to their performance and interpretability: a general FL m odel, FL models for the 2 years of the Speulderbos, and a forest growth mod el parameterized for Douglas fir. The performance of the FL models was clos e to optimal. The rules of the FL models made objective model comparison po ssible and showed a change in the sensitivity to vapor pressure deficit of the Speulderbos. Fuzzy logic proved to be a very promising method for top d own modeling of forest gas exchange, systematic model evaluation, and model simplification.