Coffee Hour: Self-reinforcing patterns of fire severity

Friday, January 18, 2013 - 3:30pm to 5:00pm
• Refreshments are offered in the E. Willard Miller seminar room, 319 Walker Building at 3:30 p.m. • The lecture begins at 4:00 p.m. in the John J. Cahir Auditorium, 112 Walker Building at 4:00 p.m.

Self-reinforcing patterns of fire severity in a mixed conifer forest landscape, southern Cascades, USA.

Fire severity in mixed conifer forests in California has increased in the recent decades due in part to fire suppression and fuel build up. This has resulted in more severe fire effects in these ecosystems. 

In 2008, the Cub Fire burned through a watershed with an earlier fire history study (1997) that identified fire severity patterns in the 19th century. No logging had occurred in this watershed so differences in fire severity between the late 19th century and 2008 are related to fire history, vegetation structure, topography, changes in vegetation and fuels since fire suppression, and weather conditions during the fire.

This work tests the working hypothesis that fire severity patterns in 2008 are driven mainly by fire severity patterns in the 19th century. In other words, patterns of fire severity are self-reinforcing and tend to be fixed in place. At the landscape scale, fire severity in 2008 was greatest where fire severity was greatest in the 19th century, on upper and mid-slope positions, and lowest on lower slope positions. This is the same fire everity pattern present in the 19th century landscape and supports the view that patterns of fire severity are self-reinforcing over long periods of time, at least in complex terrain. The lifting of an atmospheric inversion also contributed to fire severity patterns. In Cub Creek, fire severity patterns promote persistence of old forests with a multi-layered canopy in valley bottoms and on lower slopes and young dense forests on upper slopes.

 See attached article below for more background information


About the speaker

Alan Taylor is  a professor of geography at Penn State and the director of the Vegetation Dynamics Lab. He has broad research interests in ecological biogeography and vegetation dynamics, particularly the role of natural and human disturbance and climate variation on forest dynamics. Much of his recent research has focused on identifying the influence of changes and interactions of land use history and climate on fire disturbance and forest conditions in the western United States.