This maple tree fell on a 23-year-old woman Wednesday morning.

A Calgary arborist says a maple tree that fell on a 23-year-old woman, sending her to hospital,had root damage.

Codie Anderson, a master arborist at ArborCare, saidonly a trained expert would havecaught the signs of rootrot warning that the tree on 25th AvenueSouthwestwas going to fall.

The woman was hit by the tree Wednesday morning following a storm that swept through the city. She was taken to the Foothills Medical Centre with serious, but notlife-threatening, injuries.

Large trees should be inspected every year to make sure they are healthy,Anderson said.

Homeowners can keep an eye out for some signs, such as odd-coloured leaves, that appear on partially broken branches that could come down in a storm. But root damage is common and can be more dangerous, he said.

"Everyone looks up when they're looking at their trees. Looking down is especially important. That's what anchors them, and if there are problems at the ground level, it can affect what happens above."