Dry deposition of nitrogen and sulfur to ponderosa and jeffrey pine in the San Bernardino National Forest in southern California

Abstract

Little is known about the concentrations, deposition rates, and effects of nitrogenous and sulfurous compounds in photochemical smog in the San Bernardino National Forest (SBNF) in southern Calfirnia. Dry deposition of NO₃^- and NH₄⁺ to foliage of ponderosa pine (Pinus ponderosa Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Bay) was correlated (R = 0·83-0·88) with historical average hourly 0₃ concentrations at 10 sites across an O₃ gradient in the SBNF. Mean deposition fluxes of NO₃^- to ponderosa and Jeffrey pine branches were 0·82 nmol m^-2 s^-1 at Camp Paivika (CP), a high-pollution site, and 0·19 nmol m^-2 s^-1 at Camp Osceola (CAO), a low-pollution site. Deposition fluxes of NH₄⁺ were 0·32 nmol m^-2 s^-1 at CP and 0·17 nmol m^-2 s^-1 at CAO , while mean values for SO₄^-2 were 0·03 at CP and 0·02 nmol m^-2 s^-1 at CAO . Deposition fluxes to paper and nylon filters were higher in most cases than fluxes to pine branches at the same site.

Citation

Fenn, Mark E.; Bytnerowicz, Andrzej. 1993. Dry deposition of nitrogen and sulfur to ponderosa and jeffrey pine in the San Bernardino National Forest in southern California. Environmental Pollution 81:277-285