MISSOULA, Mont. -

This week crews began removing close to 100 'hazard' trees in the neighborhoods surrounding downtown Missoula.

City officials tell they'll then plant around 200 new trees.

The work is part of a long term urban forest renewal plan that's focused on maintaining the health of Missoula’s aging tree population.

We're told most of the trees being removed were planted in the neighborhoods surrounding downtown more than 100 years ago and have reached the end of their lifespan.

"Many generations have enjoyed those trees,” said Missoula Urban Forester Chris Boza. “We need to take the proactive step of ensuring that the urban forest is here for future generations."

We're told the project is costing a little less than $23,000.