© 1991 Heron Publishing—Victoria, Canada
Winter desiccation and injury of subalpine red spruce
Graham T. Herrick and Andrew J. Friedland
Environmental Studies Program, Dartmouth College, Hanover, NH 03755, USA / Received April 3, 1990
Summary
Montane red spruce (Picea rubens Sarg.) in the northeastern United States has undergone a decline during the past two decades. One symptom associated with
the decline syndrome is the episodic browning of first-year foliage in early spring. To examine the potential role of winter
desiccation in this browning, the water relations of red spruce foliage in a subalpine forest on Mt. Moosilauke, New Hampshire,
USA, were monitored from January to May, 1989. All sampled trees lost water during the winter and the first-year foliage on
some trees turned brown in early spring. The relative water content of first-year shoots during the winter was a significant
predictor of spring browning; red spruce trees that showed browning had desiccated faster and reached lower relative water
contents. Damaged trees also had more closely packed needles and lower cuticular resistances to water loss. The first-year
shoots had a significantly lower average relative water content than older shoots before and after browning. Cuticular resistance
to water loss decreased with elevation. Sun-exposed shoots lost more water than shaded shoots because of solar heating of
needles. Winter desiccation can occur before the decline-related spring browning of red spruce foliage.
