A 5-year-old boy in Arthur has been airlifted to a trauma centre with life-threatening injuries after he hit a tree while riding a dirt bike Wednesday evening.

The collision happened at dusk, around 6:30 p.m. Police say it appeared the boy lost control of the dirt bike.

Wellington OPP said the boy was wearing a helmet at the time. He was riding the 50 cc dirt bike on private property.

Guelph Wellington Paramedics took the boy to a local hospital before he was airlifted to the trauma centre.

The cause of the collision is under investigation.