In Wisconsin and much of the upper Midwest, oak savanna with an intact groundlayer has long been considered extremely rare and imperiled. More recent consideration of the nature of oak savanna and its restorability suggest that large areas could be relatively easily restored by thinning canopies and reintroducing fire. Savanna plants’ adaptations to fire and high light levels, at first glance, seem to make them also tolerant of the warmer conditions expected in the future. To more deeply explore the potential effects of change climate on on-going and proposed oak savanna restoration projects we selected five areas in southern and west-central Wisconsin and for each generated climate projections at the 1/8th degree scale to address issues relevant to oak savanna restoration. 1) The ability to conduct prescribed burns with few equipped and trained crews is limited by the number of days within parameters. Will projected changes in temperature, relative humidity, wind speed, and other factors allow for increased use of prescribed fire? 2) In what way will changes in weather patterns, such as summer droughts, limit the growth of forest species and favor savanna species? 3) How might differences in soils, ranging from sand to loamy silts, interact with climate to affect savanna restorations?
Results/Conclusions
The models reveal a complex story, with variation across sites. Summers will be warmer (2-4 C by end of century), drier or about the same, with more rain as convective storms, and droughts may be shorter and affect smaller areas. These changes should have some effect on savanna vegetation, especially on deep well-drained sands, but that effect may less on other soil types. Drier falls may increase the number of fall burn days. Because of increased spring precipitation, there may be years in the spring with very few burn days. Overall, the projected climate changes should not inhibit savanna restoration and may favor it.
