Freezing injury to montane Picea rubens; the potential role of and mechanisms for natural and anthropogenic perturbations
- Univ. of Vermont, Burlington, VT (United States)
Winter injury occurs frequently to current-year needles of red spruce in the northern Appalachians and appears to be caused by subfreezing temperatures rather than foliar desiccation. Under ambient conditions, the maximum depth of cold tolerance achieved by red spruce needles in midwinter is barely sufficient to avoid freezing injury at common winter temperatures. Therefore, any perturbation that would decrease midwinter cold tolerance by just a few degrees substantially increases the probability of freezing injury. Laboratory and field experiments have demonstrated that extended winter thaws and exposure to ambient and simulated acidic cloud water increase the freezing sensitivity of red spruce. Repeated experiments have been unable to demonstrate a consistent negative influence of ambient or elevated ozone concentrations or elevated N on cold tolerance or freezing injury susceptibility. Rapid freezing, especially following solar heating of needles, has also resulted in some injury to both current-year and year-old needles, under laboratory conditions. Visible freezing injury and winter cold tolerance appear to be associated with relatively low foliar Ca concentrations. It is hypothesized that Ca leaching by acidic cloud water could increase freezing susceptibility by modifying membrane structure and/or permeability.
- OSTI ID:
- 7162253
- Report Number(s):
- CONF-940894-; CODEN: BECLAG
- Journal Information:
- Bulletin of the Ecological Society of America; (United States), Vol. 75:2; Conference: Annual Ecological Society of America (ESA) meeting: science and public policy, Knoxville, TN (United States), 7-11 Aug 1994; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID RAIN
BIOLOGICAL EFFECTS
CALCIUM
ECOLOGICAL CONCENTRATION
LEAVES
FREEZING
NUTRITIONAL DEFICIENCY
SPRUCES
ALKALINE EARTH METALS
ATMOSPHERIC PRECIPITATIONS
CONIFERS
ELEMENTS
METALS
PINOPHYTA
PLANTS
RAIN
TREES
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