What are those green bags on Cornwall trees?

Cornwall Parks Supervisor Scott Porter shows off new slow-release watering bags the city is using for municipal trees during a presentation to the Cornwall and District Horticulture Society on Tuesday, Aug. 13, 2019. The bags allow for a more effective tree watering during summer while saving on staff time. (Newswatch Group/Bill Kingston)

CORNWALL – In your travels around Cornwall you may have seen green plastic bags at the base of some city trees.

They are part of a watering experiment by the city’s parks and recreation department.

The large plastic bags – there are 20 being used right now – clip around the tree and have microscopic holes that allow a slow release of water.

During a presentation to the Cornwall and District Horticulture Society Tuesday night, Cornwall Parks Supervisor Scott Porter said it’s a more effective way of watering during the very hot weather.

A sudden blast of water during traditional watering either runs off or evaporates in the heat, Porter explained, but the slow-release bags allow the trees to suck up most of the water over a six to eight hour period.

The bags also save on staff time where watering of trees is required three times a day. All the workers have to do is fill them up and go on to the next job.

The reusable bags cost about $30 each.