Climate and disturbance factors affecting shifts between grassland and forest biomes over the past century within the upper Midwest

Project Leader: 
Research Partners: 
Dr. Brian Palik (USFS Northern Research Station); Dr. Shawn Fraver (University of Maine); Dr. John Almendinger (Minnesota Department of Natural Resources); Dr. Kurt Kipfmueller (University of Minnesota); Dr. Michael Falkowski (University of Minnesota)
Project Fellows: 
Science Themes: 


This project aimed to quantify the range in variability in forest dynamics and climate responses for range-margin populations of Pinus banksiana and Picea mariana so as to generate management guidelines for conserving these forests on the landscape in an uncertain climatic future.  These species are the cornerstone for several upland and lowland habitat types on the western edge of the Northeast CSC and are particularly vulnerable to future changes in climate and disturbance regimes.  This project took advantage of extensive dendrochronological and forest community data to determine the drivers and future dynamics of key demographic processes for these tree species.

Preliminary Results

Detailed dendrochronological reconstructions of the age-structure and growth patterns of range-margin Pinus bansksiana forests indicate largely uneven-aged populations that have recruited in response to low intensity surface fires followed by favorable climate regimes. Results highlight the importance of early season moisture surpluses, as quantified by precipitation/potential evapotranspiration, to long-term recruitment and survival of this species at this portion of its range.  Successional patterns for these range margin Pinus populations indicate a shift towards oak-dominated woodlands with little to no conifer component and indicate the potential for regional decline in this forest type with fire suppression and shifts towards drier climate conditions. Assessments of the impacts of a rare, stand-replacing fire event on range-margin peatland forest habitats also indicate the potential for phase shifts following such events.  In particular, Sphagnum peat was consumed to down to the water table in many tamarack-dominated areas experiencing high severity fire impacts resulting in loss of tree cover and a shift to cattail-dominated habitats.  These dynamics may become increasingly common in light of predicted increases in drought for this portion of the NECSC with forested peatland communities respresenting one of the most vulnerable habitats to climate change impacts in the region.  Moreover, assessments of forest regeneration in areas impacted by eastern larch beelte in these lowland communities indicate little to no tree regeneration in areas not experiencing follow up seeding treatments.  These results suggest this the recent outbreaks of this native bark beetle may compound drought impacts on these systems.

Stakeholder Need Addressed

The deliverables from these projects address stakeholder needs related to developing forest management and conservation strategies that confer resistance and reslience to climate change and disturbance impacts.  In addition, work is identifying conservation priorities as it relates to potential refugia for spruce-fir obligate bird species. Beyond scientific publications, projects are focused on developing management recommendations at spatially relevant scales for assisting natural resource management decisions related to climate change impacts in the region.  These recommendations are integrated into on-line platforms and shared via continuing education offerings, including workshops and field tours.

  • Gill, K.G., A.W. D’Amato, and S. Fraver. 2016. Jack pine stand recruitment and development in Central Minnesota. Presentation and discussion panel  for Sustainable Forests Educational Cooperative Fire in Minnesota’s Forests workshop, Grand Rapids, MN. December 1, 2016
  • Gill, K.G., A.W. D'Amato, S.Fraver, J. Almendinger, N. Aaseng.  2015. Structure and dynamics of range margin Pinus banksiana populations in Minnestoa, USA. North American Forest Ecology Workshop, Veracruz, Mexico. June 15, 2015.
  • D'Amato, A.W., S. Fraver, J.B. Bradford, and B.J. Palik. 2015. Salvage logging within the context of interacting disturbances in sub-boreal pine systems. Symposium on the Ecological and Sivilcultural Consequences of Disturbance and Salvage Logging on the Sustainability and Biodiversity of Forest Ecosystems. Powdermill Nature Reserve, Rector, PA. May 31, 2015
  • Gill, K.G., A.W. D'Amato, and S. Fraver. 2015. Structure and dynamics of jack pine forests in central Minnesota. Sustainable Forests Education Cooperative Wildlife and Forest Research Review. Cloquet, MN. February 24, 2015.
  • D'Amato, A.W.  2014.  Long-term structural and compositional development of fire-origin red pine forests in north-central Minnesota.  Lake States Fire Consortium Webinar Series. November 20, 2014.
  • D'Amato, A.W. 2014. Developing forest adaptation strategies for northern forests in an uncertain future.  Northeast Climate Science Center Fall Webinar Series.  October 1, 2014.
  • Gill, K.G., A.W. D'Amato, and S. Fraver, 2013. Quantifying the range in variation in climate response and stand dynamics within range-margin jack pine (Pinus banksiana) populations in north-central Minnesota, USA. Graduate Climate Conference, Wood's Hole, MA. November 2, 2013.