Natural Resources - Bark Beetle
Issue: Widespread Piñon Mortality in Northern New Mexico
Background
Piñon-juniper woodlands
occupy about 9 million acres in New Mexico. Decades of above-average
precipitation have allowed piñon and juniper trees to
proliferate in what were formerly sparse woodlands and grasslands.
Excessive tree densities coupled with several years of winter
drought have resulted in piñons being moisture-stressed
and vulnerable to attack by bark beetles. These bark beetles
have a high reproductive capacity and under optimal conditions
can produce up to 4 generations per year. Even healthy trees
can be overcome when “mass attacked” by large numbers
of bark beetles. While piñon mortality across all age
groups has been increasing over the past 3 summers, the cumulative
effect on the landscape is now noticeable to even the most casual
observer.
Current Situation
Thousands of dead and dying piñons now dot the piñon-juniper
woodlands of northern New Mexico. This summer, the visual impact
of the fading crowns reached startling proportions. While ground-checking
by Forest Service entomologists revealed piñon ips, Ips
confusus, to be at epidemic levels, the drought-weakened condition
of the piñons is a predisposing factor. Some juniper mortality,
a direct result of the drought, was also observed. The Forest
Service has provided information on this subject in a meeting
with officials from the Town of Cochiti Lake, at a public meeting
in Los Alamos, and on numerous telephone calls from affected
landowners. An article entitled, “Why Are So Many Piñons
Dying?”, written for the children’s journal, Amigos,
(circulation 17,000) is in press.
Piñon mortality viewed from Highway 285, 6 miles from
Ojo Caliente, NM.
Prognosis
Due to the cause and scale of the mortality, little
can be done to save the woodland piñons. Homeowners or
managers of developed recreation sites can use an insecticidal
spray on the trunk and larger limbs of uninfested high-value
trees as a protective treatment. On larger trees, this can require
the services of a professional applicator. The loss of so much
piñon could shift the woodland species composition to
greater numbers of junipers. If the drought persists, more junipers
and trees at higher elevations could also be affected. An increase
in ponderosa pine mortality from other species of bark beetles
has already been documented during the Forest Service’s
insect and disease aerial detection surveys this summer. Thinning
can improve tree vigor in the long term, but the green slash
generated by such activities can serve as ips breeding material
if not properly handled. Plans for increased awareness about
the impact of drought and insects on our forests include press
releases, continued literature dissemination, and additional
participation in public forums.
Contacts
Southwestern
Region
Regional Office
333 Broadway SE
Albuquerque, NM 8102 |
Debra Allen-Reid, Entomologist |
(505) 842-3286 |
Douglas Parker, Entomologist |
(505) 842-3280 |
Terry Rogers, Entomologist |
(505) 842-3284 |
Regis Cassidy, Regional Silviculturist |
(505) 842-3480 |
|
