PARENT SESSION
Contributed Oral Session 24: Disturbance Ecology: Management; Response to Fire
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 516 D, Level 5, Palais des congrès de Montréal
Human-drought-fire-interactions in Ozark forests.
Muzika, Rose-Marie*,1, Guyette, Richard 1, Voelker, Steven1, Stambaugh, Michael1, 1 University of Missouri, Columbia, MO
ABSTRACT- Forests are influenced by the interactions of human population density, fire and climate. Quantitative relationships among these factors can be used to address questions of human forest interactions that could reveal how human population density influences the relationship between drought and wildfire. Models developed from such relationships could help explain if wildfires result from climate conditioned fuels and drought-inspired human ignitions. We examine the evidence and logic in human-climate-fire interactions and their effects on forests during stages in fire regimes. In fire regimes with few lightning ignitions the effects of drought on fire occurrence are often not realized without human ignitions. For example, in the Ozark Highlands, the extent of wildfire is highly correlated (r = -0.44, p = 0.004) with drought (PDSI) during periods ( years 1850-1890) with abundant anthropogenic ignitions but weakly correlated (r = -0.15, p = 0.014) during periods (years 1700-1849) with low human population density. While there is no necessary causation, logic, or connection between drought and the number of incendiary fires, there is an association. For example, drought (PDSI) is significantly correlated with the number of arson fires in Missouri: r = -0.76. Additionally, fire suppression has increased stand density (numbers of trees / ha) that have caused increased susceptibility to pathogens and dieback from inciting factors such as drought. Reduced fire disturbance combined with episodic logging events have combined to create a more vulnerable and single cohort forest structure.
Key words: fire, drought, forests, dendrochronology