NASHVILLE (AP) - A study by the U.S. Forestry Service finds that trees in Tennessee's urban areas provide the state with environmental benefits valued at nearly $640 million a year.

According to the study's findings, reported by WPLN-FM (http://bit.ly/GSTgHx), shade trees save the state about $66 million a year. That's mostly savings in heating and cooling expenses as the trees protect rooftops from the summer sun and block cold winds in winter.

The state's urban trees also store and remove from the air more than $570 million worth of pollutants each year.

The study is meant to set a baseline for measuring the future health of the state's urban forest.

Tim Phelps of the state Forestry Division says knowing the economic value of trees helps make the case for planting and protecting them.