Over the last several years, natural resource researchers and managers are using new computer modeling tools to understand the role that protecting tree canopy plays in protecting water quality. What they have found is that trees and the canopy that their leaves create are important to protecting water quality, even if the trees are not next to a lake, river or stream.  Trees and forests serve watersheds by preventing erosion, filtering contaminants before they enter a waterway, absorbing rainfall and snow melt, recharging aquifers, and slowing storm water runoff.