We are working to modernize the process of high throughput, low cost paleoenvironmental time series data development using tree rings. Leveraging emerging technologies, our vision is to produce high quality and ultra high resolution image archives to complement entire collections of physical specimens, and to develop open source tools for image analyses and curation.

Climate, fire & savanna tree growth in a long-term burn experiment

In Minnesota, the interaction of fire and climate modulate oak tree dominance in the increasingly rare savanna ecosystem. Our group is working to disentangle the effects of fire and climate on oak savannas using a synthesis of experimental and observational data. We have focused our efforts at Cedar Creek Ecosystem Science Reserve, a LTER in eastern Minnesota where generations of scientists have made seminal contributions to modern ecological theory. Working with staff and scientists at Cedar Creek, we produced a large tree-ring dataset to study fire history, dendroclimatology, tree allometry, oak recruitment, and ecosystem biogeochemistry. This work is supported by the US NSF Division of Environmental Biology, award 1655144.

Figure: historical aerial imagery for 1938 (A) and 2016 (B) of the long-term burn experiment at Cedar Creek. Panels C - F illustrate stand level differences in canopy openness from 1938 to 2016. Source: MHAPO.

Winter climate extremes over North America

With a focus on extreme events and the winter season, we are researching atmospheric circulation and related hydroclimate across North America. Through synthesis of paleoclimate proxy data, modern records, and output from model experiments, we will test hypotheses about recent increases in winter season climate variability and spatial synchrony within a multi century framework. This collaborative project involves a substantial component of tree-ring dataset development in California and around the Lake Superior region, and connects the UMN Griffin Lab with Steve Voelker's team at SUNY ESF, and Simon Wang's Climate Dynamics group at Utah State University. This work is supported by the US NSF Paleo Perspectives on Climate Change (P2C2) program, award 1903504 .

Figure: Composite anomaly map of water year precipitation for extreme wet years in central California, data from PRISM.


GriffinLab & Minnesota Dendro CollectiveDepartment of Geography, Environment & Society UNIVERSITY OF MINNESOTA