Deposition of Water and Cations on Artificial Foliar Collectors in Fir Krummholz of New England Mountains

Abstract

Atmospheric depositions of water, calcium, magnesium, sodium, potassium, and lead were measured in an Abies balsamea krummholz ecosystem in New Hampshire, U.S.A. Two types of collectors were used. Open buckets captured rainout, washout, and sedimentation (bulk precipitation), while buckets with attached artificial conifer foliage collected intercepted aerosols and cloud droplets as well as bulk precipitation. Water catchment averaged 4.5 times greater in the foliar collectors than in open buckets, and calcium, magnesium, sodium, potassium, and lead deposition averaged 8.3, 6.0, 4.9, 5.7, and 5.5 times greater, respectively, in the foliar collectors. Most of the increase in foliar collectors was due to higher volume catchment but some concentration enrichment through interception was also contributory. These data cannot be extrapolated to elemental deposition per unit area without correcting capture efficiency of collectors to that of natural vegetation. These data do strongly suggest, however, that in areas of high wind and frequent exposure to clouds or fog, such as in montane areas of New England, measurements of total elemental deposition require an evaluation of interception as well as bulk precipitation.