%0 Journal Article
%T Early 20<sup>th</sup>  Century Climate-Driven Shift in the Dynamics of Forest Tent Caterpillar Outbreaks
%A Barry J. Cooke
%A Jens Roland
%J American Journal of Climate Change
%P 253-270
%@ 2167-9509
%D 2018
%I Scientific Research Publishing
%R 10.4236/ajcc.2018.72017
%X Using tree-ring analysis, we show that the dynamics of forest tent caterpillar [<em>Malacosoma disstria</em> (Hbn.)] outbreaks in Alberta, Canada shifted at the turn of the 20<sup>th</sup> century from cyclic, synchronous behaviour 1850-1910 to complex, asynchronous behavior 1910-1993. This shift in dynamics coincided with the emergence in 1910 of a latitudinal gradient in outbreak stability and periodicity reflecting a similar gradient in the periodicity of winter temperatures. We postulate that the synchronizing strength of winter temperatures has diminished as a result of climate warming, and that any synchronizing strength due to inter-population migration has been superseded by regionalized patterns of periodic forcing caused by weak low-frequency variability in winter temperatures. We speculate that a decrease in polar vorticity at the start of the 20<sup>th</sup> century led to increased meridional jet stream flow and more frequent arctic weather anomalies, resulting in a loss of synchronous decadal periodicity in outbreak occurrence. These changes in insect disturbance probabilities, including rising uncertainty, have profound consequences for forest disturbance risk management.
%K Dendroentomology
%K Forest Insects
%K Outbreak Cycles
%K Synchronization
%K Disturbance Ecology
%K Climate Change
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=85270