The Old Castletown Road will shut near the Nunnery next month.
The route will be shut from 9.30am until 3.30pm on Friday, May 24.
It's as workers fell large dead Ash trees near the main gates of the facility.
Ramsey company Manx Roots, which is doing the work, says it needs to close the road because the work couldn't be done safely with traffic controls.
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