Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens)

Laboratory experiments have verified that acid-deposition-induced calcium (Ca) leaching reduces the foliar cold tolerance of red spruce (Picea rubens Sarg.) current-year foliage, increasing the risk of winter injury and crown deterioration. However, to date no studies have shown that ambient losses in soil Ca have resulted in increased winter injury in the field. In 2003, a year of severe region-wide winter injury to red spruce, we measured the nutrition and winter injury of current-year foliage and bud mortality for red spruce on two watersheds at the Hubbard Brook Experimental Forest in Thornton, New Hampshire: (1) a reference watershed that has undergone considerable Ca loss attributed to acid-deposition-induced leaching and (2) a watershed that was fertilized with CaSiO3 in 1999 to replace lost Ca. For all crown classes combined, winter injury was significantly greater (P = 0.05) for red spruce on the reference watershed than for spruce on the Ca-addition watershed. Differences in foliar injury were particularly evident for dominant and codominant trees. For these crown classes, red spruce on the reference watershed lost about 75% of their current-year foliage to winter injury, about three times more than foliar losses for the Ca-addition watershed (P = 0.01). Patterns of bud mortality followed that of foliar injury. The only difference in foliar cation nutrition detected was a significantly greater concentration of Ca in red spruce foliage from the Ca-addition watershed relative to spruce from the reference watershed (P = 0.001). Differences in Ca concentration, foliar winter injury, and bud mortality that occurred coincident with watershed Ca treatment provide the first evidence that ambient Ca depletion is associated with elevated winter injury of red spruce trees.

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Effects of chronic N fertilization on foliar membranes, cold tolerance, and carbon storage in montane red spruce

Canadian Journal of Forest Research ◽

10.1139/x02-059 ◽

2002 ◽

Vol 32 (8) ◽

pp. 1351-1359 ◽

Cited By ~ 41

Author(s):

Paul G Schaberg ◽

Donald H DeHayes ◽

Gary J Hawley ◽

Paula F Murakami ◽

G Richard Strimbeck ◽

...

Keyword(s):

Cold Tolerance ◽

N Fertilization ◽

Picea Rubens ◽

Control Plot ◽

Membrane Stability ◽

Red Spruce ◽

Freezing Injury ◽

N Addition ◽

Cell Membrane Stability ◽

Induced Changes

We evaluated the influence of protracted low-level nitrogen (N) fertilization on foliar membrane-associated calcium (mCa), sugar and starch concentrations, membrane stability, winter cold tolerance, and freezing injury of red spruce (Picea rubens Sarg.) trees growing in six experimental plots on Mount Ascutney, Vermont. For 12 consecutive years before this evaluation, each plot received one of three treatments: 0, 15.7, or 31.4 kg N·ha1·year1 supplied as NH4Cl. In comparison with trees from control plots, the current-year foliage of trees from N-addition plots had lower mCa concentrations, higher levels of electrolyte leakage, reduced cold tolerance, and greater freezing injury. Levels of mCa, membrane stability, and cold tolerance did not differ between N treatments, but trees in high-N treated plots experienced greater freezing injury. Although no differences in carbohydrate nutrition were detected in September, foliar sugar and starch concentrations from trees in N-treated plots were higher than control plot trees in January. We propose that foliar mCa deficiencies reduced cell membrane stability, decreased cold tolerance, and increased freezing injury for trees in N addition plots relative to controls. Declines in mCa may also help account for increases in respiration previously measured. Because soil, root, and mycorryhizal conditions were not evaluated, it is unknown how treatment-induced changes in these compartments may have influenced the alterations in foliar mCa and physiological parameters measured in this study.

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