Winter damage to foliage as a factor in red spruce decline

Abstract

Observations made over the past 5 years suggest that the most recent needles of red spruce (Picearubens Sarg.) in the Green Mountains of Vermont, U.S.A., are prone to browning and loss owing to cold stress and (or) winter desiccation. Particularly severe events occurred in the winters of 1981 and 1984 and the latter event was observed in detail. On many trees in all size classes, a large proportion of the 1983 needles turned reddish-brown between late February and early April, 1984. This pattern of discoloration and subsequent defoliation, which appears to be repeated periodically, can account for the visual symptoms of declining red spruce in the montane forests of the northeastern United States. A predisposition to winter damage appears to be a component of the decline and could result from natural or possibly anthropogenic factors.

Natural abundance 15N in soil and litter across a nitrate-output gradient in New Hampshire

“…As an ecosystem nears nitrogen saturation, nitrate loss in surface water increases and may lead to harmful ecological effects. These may include: (1) soil and surface water acidification (Reuss and Johnson, 1986); (2) deterioration of both water quality in groundwater used for drinking (Skeffington and Wilson, 1988;Hauhs et al, 1989) and of coastal waters via eutrophication (Nilsson and Grennfelt, 1988;Fisher et al, 1988); and (3) plant nutrient imbalances that have been implicated in forest decline (Friedland et al, 1984;Waring, 1987;Schulze, 1989;Aber et al, 1995).…”

Community and population dynamics of spruce–fir forests on Whiteface Mountain, New York: recent trends, 1985–2000

“…The decline has been directly linked to freezing injury of spruce foliage (Friedland et al 1984;Johnson et al 1988;Peart et al 1992b;Tobi et al 1995). There is good evidence from both laboratory studies (DeHayes et al 1999) and field trials (Vann et al 1992) that exposure to acidic cloud water reduces the freezing tolerance of spruce leaves.…”

Variation in overstory nitrogen uptake in a small, high-elevation southern Appalachian spruce-fir watershed

“…However, increases in atmospheric N deposition from fossil fuel combustion has greatly increased N availability in some locations often to the point where it now exceeds biological N demands (Skeffington and Wilson 1988;Aber et al 1989). There are concerns that this excess N may reduce forest productivity because of frost damage or other physiological impairments (Friedland et al 1984;Aber et al 1998), that accelerated nitrate (NO 3 ) mediated leaching may cause nutrient imbalances in the soil through cation depletion and (or) Al mobilization, and that these exports may in turn adversely impact stream water quality (Stoddard 1994;Fenn et al 1998). Disturbance and land-use history influence the rate at which ecosystems approach N saturation; in the long-term by repeated reductions in soil N capital associated with prior extractive land-use practices and, in the short term, through changes in N fluxes such as plant uptake or N mineralization following disturbance (Vitousek and Melillo 1979;Perry 1994).…”