Liquid and Chemical Fluxes in Precipitation, Throughfall and Stemflow: Observations from a Deciduous Forest and a Red Pine Plantation in the Midwestern U.S.A.

Abstract

Wet deposition (WD), throughfall (TF) and stemflow (SF) measurements undertaken in a deciduous forest show 85% of the WD liquid flux is observed as TF and approximately 2% as SF. TF and SF were observed to be enriched in base cations and accordingly had an average pH of 6.1 and 5.9, respectively relative to a WD pH of 5.1. The seasonal variability of TF pH below the deciduous canopies was more pronounced than that of WD though both exhibited a growing season maximum, and there is evidence that the seasonal variability of TF pH below the pines is inverted relative to the deciduous canopies likely due to enhanced dust capture and buffering by calcium carbonate. TF ion concentrations differed significantly between deciduous and pine canopies during the growing season, and there is some evidence that variation in sky view factor of 0.18-0.22 is sufficient to manifest statistically differing TF composition below sugar maples. The total atmospheric flux of inorganic nitrogen to the forest is approximately 14-18 kg-N ha −1 yr −1 with approximately half taken up by the canopy. Associated experiments designed to quantify uncertainties in the nutrient fluxes included laboratory tests of the Aerochem automated wet-dry sampler. These experiments indicate the delay in initiating sample collection is less than half a minute for rainfall rates above 1 cm h −1 , but may increase substantially for lower precipitation rates.

Oak leaves as aerosol collectors: relationships with wind velocity and particle size distribution. Experimental results and their implications

“…Our blank testes showed that for chloride, our tracer, Q R and Q L are both negligible (see also e.g., Cappelatto and Peters 1995;Burkhardt et al 2001b;Rea et al 2001;Pryor and Barthelmie 2005). The upper limit of m po is known in our case (prior-exposure wash-offs being close to or below detection limit).…”

“…Blank backup filter analysis showed a slight background content for Cl -, 123 lg/filter. Determination of mass collected by the leaves needs special attention in view of potential problems involved in partly related throughfall-measuring techniques (cf., e.g., Lindberg et al 1986;Lovett and Reiners 1986;Pryor and Barthelmie 2005;Watanabe et al 2008). However, our controlled wash-off technique minimizes such problems.…”

Evaluation of Bulk Deposition in Protected Woodland Area in Western Poland

“…A good measure of the human impact on ecosystems is the deposition of substances reaching them via precipitation (Forsius, Kleemola, & Starr, 2005;Himagenova, 2004;Lundin et al, 2001;Pilkington et al, 2005;Pryor & Barthelmie, 2005;Staelens, De Schrijver, Van Avermaet, Genouw, & Verhoest, 2005). The chemical character of precipitation could be defined using its acidifying potential (Vuorenmaa, 2004).…”

Precipitation Composition in the Ohio River Valley: Spatial Variability and Temporal Trends

“…All of the 220 NADP/NTN sites employ an AeroChem-Metrics wet-dry deposition sampler and Belfort 5-780 Universal recording precipitation gauge. Although concerns have been raised about exclusion of light precipitation events by the wet-dry collector due to delay in sampler opening (Claassen and Halm, 1995a,b;Pryor and Barthelmie, 2005), the data are spatially consistent and overall network precision determined from collocated samplers is typically better than ±5% for acid anions, ±10% for base cations and ±20% for NH + 4 (Nilles et al, 1994). Data for this paper were derived from weekly measurements between January 1985 and December 2002 taken from the following NADP sites; IN20, IN22, IN41, KY03, OH09, and IL11 ( Figure 2) which are all located at elevations of between 130-290 m a.s.l.…”