UC Berkeley

Ecophysiological and dendroecological data from a temperate sessile oak (Quercus petraea (Matt.) Liebl.) stand in Belgium were used to develop and parameterize a dendroecological process-based model. The purpose of this model is to serve as a tool for exploring the relationship between climate variability and tree growth based on dendro ecological data. When parameterized, the model was able to correctly simulate measurements of bud-burst date, through fall (r(2) = 0.95), soil water content (r(2) = 0.81), transpiration (r(2) = 0.80), and ring-width series from 1960 to 1999 (r(2) = 0.46). Model sensitivity analysis showed that atmospheric vapor pressure deficit is the major controlling factor of transpiration in this type of ecosystem. The model shows that bole increment is principally controlled by temperature because it affects the phenological process of bud burst and thus the growing season length. Precipitation variability does not affect variation of transpiration rate and bole increment because calculated soil water stress is negligible during the simulation period. Discrepancies between observed and simulated bole increment may be a consequence of stand density variations and worm defoliation in the spring. The MAIDEN model is particularly suited for dendreocological analysis because it takes simple species, site condition, and climatic variables as input.