Firefighters in Fredericton are warning students that a popular prank could have dangerous consequences.

Fire crews were called to two couch fires on Graham Avenue Friday night.

Captain David McKinley of the fire department said there have been seven couch fires so far this year.

He said university students are burning their furniture as an end of year tradition.

"It's most common in the spring when classes are getting out and the weather starts getting nice, people get out having a good time, and they get carried away and the next thing you know, there's some old furniture burning up," he said.

But what might seem like a harmless prank could cause serious damage, said McKinley.

The fire could spread, and it could cause damage to the road.

The fires are also expensive, as fire crews have to response to each case, he said.

McKinley said this is an ongoing issue. In 2008, there were 19 furniture fires. 

Since then, the fire department has been working with the universities, city council and local residents to try to educate people on the dangers of couch fires.