EDMONTON -- Free Christmas trees are available in Alberta and Saskatchewan this weekend, for a good cause.

The Nature Conservancy of Canada is hosting tree harvesting events on Saturday in central Alberta and near Saskatoon in an attempt to get rid of invasive spruce trees.

The trees aren't native to the Saskatoon area and their presence could actually damage the habitat for other plants and animals.

Anyone can go and cut down a free spruce tree at a property near Saskatoon that is owned by the conservancy.

In Alberta, the harvest is done and people are invited to a property in the Red Deer River area to pick up a free blue spruce tree.

The free tree harvest comes as holiday shoppers face higher costs for natural Christmas trees at retail outlets.