Forestry Seminar at NAU

What: FGSA Forestry seminar: John Guyon, Forest Pathologist, USFS, Forest Health
Title: Aspen dieback in the interior west.

When: Wednesday, March 3rd at 4pm

Where: Room 317 of the Southwest Forest Science Complex (Bldg. 82) on the NAU Campus

Abstract: Various authors have been discussing “aspen decline” since the 1970’s, but more recently events have led to increasing interest in the status of aspen forests. In the 1990’s some ecologists called attention to the apparent decrease in aspen forest coverage, while others argued that aspen forest actually increased in coverage over the longer term. Forest succession and damage to young aspen sprouts by grazing animals have been cited as critical agents in this purported decline. More recently, almost a million acres of aspen forest have shown dieback symptoms ranging from Canada to the Mexican border. The abiotic factors and biotic agents involved in this dieback vary, but drought stress, within the context of a warming climate seems to be an important factor in this dieback from several areas. Recent surveys and monitoring efforts have been conducted in Utah, Nevada, Idaho, Montana, and Wyoming, Colorado, Arizona and elsewhere. In some areas the phenomenon SAD (sudden aspen decline) has been reported, but in others SAD doesn’t not seem to be prevalent. The most important damage agents in the interior west are 3 insect borers and 2 canker diseases, and 4 out of these 5 agents have been historically more prevalent on drought stressed trees. Two aspen bark beetles are a primary cause of damage in Colorado, and appear to be increasing in occurrence in Utah. Physiological studies of aspen drought avoidance mechanisms may offer some insight into why dieback is occurring and help to explain observed patterns of dieback. Additionally, the concept of a forest decline used by plant pathologists may offer a useful framework for explaining the mechanism involved in aspen dieback and decline. Recent climatic modeling efforts predict a substantial reduction in aspen range if current climate trends continue.

If you would like to meet with John Guyon during his visit please email me at:
tjz4@nau.edu

All seminars occur on Wednesdays from 4:00 to 5:00 PM in Room 017 of the Southwest Forest Science Complex (Building 82) on the campus of Northern Arizona University. A reception for the speaker with snacks and beverages is held in the lounge area immediately outside room 017 from 3:30-4:00 PM. Students are also invited to the post-seminar discussion from 5:15-6pm. No parking permit is needed for any vehicle with state, federal, or tribal license plates in the lower Southwest Forest Science Complex lot. Others can get a free permit from the School of Forestry administrative office (Forestry room 116) prior to the seminar.