Major-Element Cycling in a High-Elevation Adirondack Forest: Patterns and Changes, 1986-1996

Abstract

High-elevation forests in the northeastern United States have received large amounts of atmospheric deposition of pollutants that may alter natural element cycling and retention rates in a variety of ways. This study examined atmospheric deposition of N, S, and base cations (Ca 2ϩ , Mg 2ϩ , K ϩ , Na ϩ ), and their impact on element cycling, in a highelevation forest on Whiteface Mountain, New York, USA. Ten years of element cycling data (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996) showed that at our study site (1050-m elevation) precipitation and cloud water contributed most of the atmospheric deposition relative to dry deposition. Inputoutput budgets revealed a net retention of N in this forest. In contrast, annual variations in outputs of K ϩ were roughly balanced by atmospheric inputs. Potassium output seemed to be strongly related to and dependent on K ϩ inputs. There was a net loss of Ca 2ϩ , Mg 2ϩ , and SO 4 2Ϫ from the site. Calcium and SO 4 2Ϫ outputs were related to one another and to water inputs to the forest. Net loss of 2.9 kg S·ha Ϫ1 ·yr Ϫ1 was likely supplied by the large mineral soil S pool. The difference between atmospheric input and ecosystem export of 7.4 kg Ca·ha Ϫ1 ·yr Ϫ1 may or may not be sustainable, depending on replacement by mineral weathering. The dominance of inorganic N species in all solutions except O-horizon leachate supports the idea that the forest is heavily impacted by N deposition. However, the decrease in NO 3 Ϫ export from the forest observed during the study and the continued accumulation of N in vegetation suggest that N saturation has not yet occurred.

Biogeochemical legacy of prescribed fire in a giant sequoia–mixed conifer forest: A 16‐year record of watershed balances

“…Throughfall N fluxes measured at the site using bulk collectors (6–11 kg N ha −1 yr −1 [ Chorover et al , 1994]) and ion exchange resin columns (11.6 kg N ha −1 yr −1 [ Fenn et al , 2003]) were higher than our estimate for inorganic N loading (3.9 kg N ha −1 yr −1 ). Net canopy retention of N, ranging from 30% to 70% of atmospheric deposition, is expected in conifer forest [ Fenn et al , 2000; Friedland and Miller , 1999; Lindberg et al , 1986; Stottlemyer and Troendle , 2001]. Hence, the true deposition rate for N in Giant Forest is probably even higher than reported throughfall fluxes.…”

“…Crown scorch, tree mortality, and stand replacement can affect canopy‐related processes that are important in watershed balances of water and nutrients. These include interception of precipitation and cloudwater [ Collett et al , 1990; Friedland and Miller , 1999; Stottlemyer and Troendle , 1999, 2001], scavenging of aerosols and gases [ Hanson and Lindberg , 1991; Norby et al , 1989; Nussbaum et al , 1993], and transpiration. Enduring effects of fire on watershed balances (decade scale) relate ultimately to changes in vegetative cover.…”

Contrasting stream water NO3− and Ca2+ in two nearly adjacent catchments: the role of soil Ca and forest vegetation

“…Although both S14 and S15 leached varying amounts of Ca 2+ and NO 3 − , these catchments both have received elevated fluxes of N and S deposition in the last four and a half decades (Driscoll et al , 2003c). Chronically high acidic deposition and subsequent acid leaching can increase base cation losses from soils above the inputs from soil weathering and atmospheric deposition (Miller et al , 1993; Kirchner & Lyderson, 1995; Likens et al , 1996; Friedland & Miller, 1999; Ouimet et al , 2001; Tomlinson, 2003; Watmough & Dillon, 2003a). Such losses of base cations, especially Ca 2+ , have been reported in the Archer Creek Catchment (Mitchell et al , 2001; Watmough et al , 2005), as well as in other forested catchments located in the northeastern US (Likens et al , 1998; Fernandez et al , 2003), the Allegheny Plateau, US (Bailey et al , 1996), Canada (Johnson et al , 2000; Watmough & Dillon, 2003a–c), and Europe (Bredemeier et al , 1998; Watmough et al , 2005).…”

Basal Area Growth of Sugar Maple in Relation to Acid Deposition, Stand Health, and Soil Nutrients

“…Many studies have shown that, for noncalcareous soils, acid deposition has increased leaching losses of basic cations above the replenishment rate from soil mineral weathering and atmospheric depositions, causing a reduction in the availability of mineral nutrients (Ulrich, 1986; Federer et al, 1989; Foster et al, 1989; Eckstein and Hau, 1992; MacDonald et al, 1992; Mitchell et al, 1992; Morrison et al, 1992; Robarge and Johnson, 1992; Kirchner et al, 1992; Miller et al, 1993; Likens et al, 1994, 1996, 1998; Hallett, 1996; Houle et al, 1997; Markewitz et al, 1998; Friedland and Miller, 1999; Lawrence and Huntington, 1999; Ouimet et al, 2001).…”