AmeriDendro 2013 registration is open: follow the link on the Overview page.
Spatial and temporal interactions between Spruce beetle outbreaks, fire, and climate in a remnant isolated spruce-fir forest
Presented by Mr. Christopher O'CONNOR on 14 May 2013 from 11:35 to 11:55
Type: Oral Presentation
Session: Dendroecology I
The Pinaleño Mountains of southeastern Arizona contain the southernmost spruce-fir forest in North America. Contemporary disturbance events in this forest include bark beetle outbreaks in the 1950s and late 1990s, endemic defoliator and exotic aphid outbreaks in the mid-1990s, and a stand-replacing fire in 2004. Using dendrochronology, we reconstructed the disturbance events and stand dynamics that followed the last stand replacing fire in 1685, and examined relationships among stand composition, climate, fire and insect outbreaks. Spruce beetle outbreaks tended to lag spruce establishment by ~40 years and were significantly correlated with persistent drought events. The area occupied by Engelmann spruce and corkbark fir nearly doubled in size from 1880 to 1950, coinciding with the first wide-spread outbreak events. Increasing size and severity of outbreaks appears to have been influenced by host range expansion due to fire suppression and host water stress during persistent 20th century droughts.