“In Coast Range and Western Cascades catchments, where our study streams were located, streams that are small and non-fish bearing have no regulatory requirement for an overstory riparian buffer,” said Kevin Bladon, lead author and assistant professor in the College of Forestry at Oregon State University. “As a result, we observed some warming of the stream water. However, if the geology is permeable — where we have a lot of groundwater inputs into the system — that warm water didn’t persist downstream. As soon as it flowed back into a forested stream reach again, the temperature stabilized.”