Designing Pest-Resistant Forest Landscapes: The Importance of Spatial Pattern.

Research Issue

Defoliating insects damage millions of acres of forested land annually in the United States.  The balance of evidence suggests forest insect outbreaks today are more damaging than ever because of changes in forest composition and structure induced by fire suppression and post-harvest proliferation of tree species intolerant to herbivory.  Our central hypothesis is that landscape connectivity of acceptable host types increases defoliator population connectivity, altering the dynamics and spatial structure of defoliator populations, and thus increasing forest susceptibility to insect pest damage.    

Our Research

We address the above hypothesis by examining spatial and temporal components of forest-insect dynamics for two major insect pests with very different life histories – spruce budworm and forest tent caterpillar – in response to regionally varying forest landscape structures.  Specifically, we are investigating: (1) spatial effects of forest landscape structure on defoliation damage, using a combination of molecular genetic techniques, remote sensing, and multi-scale pattern analyses; (2) temporal effects of changes in forest landscape structure on defoliation damage using dendrochronology, air photos, and aerial survey data; and (3) spatio-temporal implications of different land use policies on outbreak dynamics via landscape-level modeling with LANDIS - a spatially explicit forest simulator.  We are contrasting insect disturbance patterns, impacts, and landscape responses within a 2 million ha “experimental” landscape at the U.S.- Canadian border, containing wilderness plus two contrasting patterns of harvesting (coarse vs. fine).

Expected Outcomes

Our research will provide a general approach to understanding insect-forest-landscape interactions, allowing forest managers to strategically deploy resources to reduce forest susceptibility to defoliating insects.

Research Results

Anderson, D.P.; Sturtevant, B.R.. 2011.  Pattern analysis of spruce budworm (Choristoneura fumiferana) dispersal.  Ecography 34: 488-497.

James, P.M.A; Fortin, M.J.; Sturtevant, B.R.; Fall, A.; Kneeshaw, D. 2011. Modelling spatial interactions among fire, spruce budworm, and logging in the boreal forest.  Ecosystems 14: 60–75.

James, P.M.A.; Sturtevant, B.R.; Townsend, P.A.; Wolter, P.T.; Fortin, M.J.. 2011.  Two-dimensional wavelet analysis of spruce budworm host basal area in the Border Lakes landscape.  Ecological Applications 21: 2197–2209

Wolter, Peter T.; P A Townsend; B R Sturtevant. 2009 Estimation of forest structural parameters using 5 and 10 meter SPOT-5 satellite data. Remote Sensing of Environment 113: 2019-2036.

Wolter, P.T.; Townsend, P.A.; Sturtevant, B.R.; Kingdon, C.C. . 2008. Remote sensing of the distribution and abundance of host species for spruce budworm in Northern Minnesota and Ontario. Remote Sensing of Environment 112: 3971-3982.

Research Participants

Principal Investigator

• Brian R. Sturtevant, US Forest Service- Northern Research Station Research Ecologist
• Philip A. Townsend, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison
• Vanessa Quinn, Department of Biology/Chemistry, Purdue North Central, Westville, IN

Research Partners

• Daniel Kneeshaw, Centre d’Étude de la Forêt (CEF), University of Quebec at Montréal
• Marie-Josee Fortin, Ecology and Evolutionary Biology, University of Toronto
• Barry Cooke, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta
• Dean Anderson, Landcare Research - Manaaki Whenua, Lincoln, New Zealand
• Felix Sperling, Department of Biological Sciences, University of Alberta
• Peter Wolter, Natural Resource Ecology & Management, Iowa State University
• Patrick James, Département de Sciences Biologiques, University of Montreal

For further details log on website :
http://www.nrs.fs.fed.us/sustaining_forests/natural_disturbance/spatial_pattern/