Thank you for your recent, timely and in-depth
article on the horrors of increasing bark beetle infestations (HCN,
7/19/04: Global Warming’s Unlikely Harbingers). In this report,
changes in beetle life histories were targeted as the principal
effect of climate change. However, rising temperatures and drought
are apt to affect plant defenses as well.
Trees facing
the twin devils of drought-induced declines in photosynthetic
rates, and temperature-induced higher nighttime respiration rates,
are losing the very carbon-based resources needed to defend
themselves (by resins) against beetle attack. Together with the
described changes in beetle life histories, this is a frightening
picture indeed.
Diane W.
Davidson
Salt Lake City, Utah
The author is a biology professor at the University of Utah.
This article appeared in the print edition of the magazine with the headline Trees face twin devils.
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