Do Open Grown Oaks Indicate Former Savanna?

One method for identifying former oak savannas is identifying open grown oaks. However, some of these large, open-grown trees have established post-settlement. Further complicating the ability to identify former oak savannas is the lack of historical records at some sites, making human impacts of logging, farming, grazing, and oteher disturbances unknown.

Authors of this study conducted in central Iowa hypothesized that tree recruitment would be related to site history, and that the open-grown oaks which would be seen as indicators of savanna habitat may have established post-settlement.

Of the results, the most notable may be that the open-grown oaks on this site were established post-settlement. The open-grown characteristics likely developed as the result of a savanna-like landscape being maintained through grazing and possibly periodic fire.

For a summary of the study's results and implications for management, you can view or download a PDF version of "Do Open Grown Oaks Indicate Former Savanna?"

This research brief for research managers summarizes the following peer-reviewed publication:

Karnitz, Holly, and Heidi Asbjornsen. 2006. Composition and age structure of a degraded tallgrass oak savanna in central Iowa. Natural Areas Journal 26:179-186.