Cowling Arboretum ===
Since 1970, acreage has been removed from cultivation in sections. The Arboretum has approximately 800 acres (320 ha) of restored and remnant forest, Cannon River floodplain, bur oak (Quercus macrocarpa) savannah, and tallgrass prairie. The Arboretum is divided by Minnesota Highway 19 into the larger Lower Arb to the north (so-called because it includes the Cannon River valley) and the smaller Upper Arb. Pedestrian trails are located throughout the Arboretum, as well as the school's cross-country running and skiing courses, and a paved mixed-use bicycle/running trail in the Upper Arb.
=== Sustainability ===
The College Sustainability Report Card, which evaluated 200 colleges and universities with the largest endowments in the United States and Canada, Carleton received a grade of A−, earning the award of "Overall College Sustainability Leader". A wind turbine located near the campus generates the equivalent of up to 40 percent of Carleton's electrical energy use; it is configured to sell …
