'Problematic trees' along the river near Tromode Bridge will be removed this week.
The Department of Infrastructure says the work is required to protect riverside structures and reduce the risk of fallen trees causing damage.
It comes ahead of future flood alleviation works in Douglas.
Temporary traffic lights will be in place on Wednesday at the junction of Johnny Watterson Lane, Ballafletcher Road and Tromode Road so the trees can be felled safely.