 The Dubuque region is relatively far south for the white pine to thrive.White Pine Hollow, part of the Driftless Area, is a patch of north-facing algific talus slope land, a subset of dolomite karstland with many sinkholes, caverns, and other sharp changes in elevation.The conifer population may have established itself here at a time when the climate of Iowa was colder than it is today, and this grove could be a relict of what was once a much larger population.