ABSTRACT
A predictor was developed to estimate seasonal surface dry deposition of nitrogenous (N) air pollution to a mixed conifer forest in the San Bernardino Mountains. The estimator requires only foliar rinse measurements at the canopy top, and leaf and branch area estimates by species for the site. The model assumes that the forest lacks a vertical atmospheric concentration gradient, and that NH4NO3 is the dominant form of particulate ammonium and nitrate. The model was applied to a intensive study site, Barton Flats, located on the eastern side of the San Bernardino Mountains. Seasonal dry surface deposition for three tree species were estimated and then compared with foliar 1inse and throughfall estimates for the summer of 1993. The model estimate of summertime dry surface deposition (3.44 kg N/ha) falls within the range of the foliar rinse estimate (4.22 kg N/ha) and the throughfall estimate 18(2.95 kg N/ha) for the same time and location. This approach has potential for reducing the number of field and laboratory measurements needed to obtain reliable seasonal surface deposition estimates for many dry forest, shrub, and savanna systems.
