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Girardin, M.P., Bouriaud, O., Hogg, E.H., Kurz, W.A., Zimmermann, N.E., Metsaranta, J., de Jong, R., Frank, D.C., Esper, J., Büntgen, U., Guo, X.J. and Bhatti, J. (2016) No Growth Stimulation of Canada’s Boreal Forest under Half-Century of Combined Warming and CO2 Fertilization. Proceedings of the National Academy of Sciences of the United States of America, 113, E8406-E8414.

has been cited by the following article:

• TITLE: Early 20th Century Climate-Driven Shift in the Dynamics of Forest Tent Caterpillar Outbreaks

  AUTHORS: Barry J. Cooke, Jens Roland

  KEYWORDS: Dendroentomology, Forest Insects, Outbreak Cycles, Synchronization, Disturbance Ecology, Climate Change

  JOURNAL NAME: American Journal of Climate Change, Vol.7 No.2, June 13, 2018

  ABSTRACT: Using tree-ring analysis, we show that the dynamics of forest tent caterpillar [Malacosoma disstria (Hbn.)] outbreaks in Alberta, Canada shifted at the turn of the 20th 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as a result of climate warming, and that any synchronizing strength due to inter-population migration has been superseded by regionalized patterns of periodic forcing caused by weak low-frequency variability in winter temperatures.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 20th 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.