A Comparison of Atmospheric Exposure Conditions at High- and Low- Elevation Forests in the Southern Appalachian Mountain Range

Acid-base chemistry of high-elevation streams in the great smoky mountains

“…The major ions in precipitation at the low-elevation Elkmont station are H § and SO42-. Data from 1986 for high-and low-elevation sites in the Smokies show that precipitation concentrations of SO4 z-, NO3-, Cl-, H § and NH4 + at the high-elevation site were within 10% of those at low-elevation sites (Lindberg et al, 1988). However, as a consequence of greater dry deposition and deposition associated with cloud and fog immersion at the high-elevation site, atmospheric deposition of major ions (H § SO4 >, NO3-) at the high-elevation site is greater by a factor of 2 to 5 than that at the low-elevation site (Lindberg et al, 1988).…”

“…Lower NO 3-export during the growing season is caused by NO 3-uptake in the watershed. Enhanced export of NO 3-during the dormant season is likely caused by a combination of (1) lower uptake, (2) a greater atmospheric deposition during this season, particularly from elevated cloudwater concentrations of acidic substances (Lindberg et al, 1988), and (3) rates of organic matter decomposition and nitrification that exceed the plant requirement of NO 3-during the dormant season (Johnson et al, 1991). The observation that no seasonal NO 3-difference existed at WP-4 and a seasonal difference existed at WP-5, which is adjacent to WP-4, suggests that atmospheric deposition is not the sole cause of the seasonal trend.…”

New Approaches to the Analysis of Population Trends in Land Birds

“…One possible causative factor of declines in upland areas is atmospheric pollution (see review by Graveland 1990), a known correlate of elevation in the eastern U.S. (Lindberg et al 1988, Shriner et al 1990). and survival of marked birds in these areas.…”

Soil Carbon Dynamics Along an Elevation Gradient in the Southern Appalachian Mountains

“…Furthermore, warming could negatively impact high elevation forests more than those at low elevations by contributing to disruption of the N cycle (Joslin and Wolfe, 1993;Joslin and Johnson, 1998;Melillo et al, 2002). *Details about the hypothesized effect of N availability on litter decomposition are explained by Berg and Matzner (1997) and Berg et al (2001) Townsend et al (1995; Trumbore et al (1996); Chambers (1998); Conant et al (1998);Garten et al (1999);Wang et al (2000); Kane et al (2003) Lindberg et al (1988Lovett and Kinsman (1990);Miller et al (1993);Garten and Van Miegroet (1994); Lawrence et al (2000); Bohlen et al (2001) Knoepp and Swank (1998) Conant et al (1998);Conant et al (2000); Wang et al (2000) reduced decomposition rates and longer turnover times increase soil C stocks greater soil N availability contributes to higher soil C stocks through effects on decomposition* poor substrate quality limits N mineralization decomposition rates increase from xeric to mesic sites (up to a limit where saturation inhibits decomposition) On the other hand, hypotheses about changing litter C:N ratios and higher limit values to litter decomposition (Berg et al, 1996;Berg, 2000) suggest a negative feedback on global warming as a consequence of greater humus formation (Berg and Matzner, 1997;Berg et al, 2001) and reduced decomposition losses of forest soil C in a N-rich environment. Emissions of nitrogen oxides from fossil fuel combustion and the use of inorganic N fertilizers in the USA more than tripled during the last four decades of the 20th century (Howarth et al, 2002).…”

“…3). Typically, high elevation forest ecosystems in the southern Appalachian Mountains receive more atmospheric N deposition than low elevation forests (Lindberg et al, 1988;Lovett and Kinsman, 1990). The annual total flux of N to high elevation (1740 m) sites is ≈28 kg N ha -1 and that to low elevation sites is on the order of 6 to 14 kg N ha -1 (Lovett and Lindberg, 1993).…”