Emergency crews were called to reports of a fire in Wollaton Park.
A fire had taken hold of two areas in the walled garden of the park, where volunteers have been working to restore the site.
The fire was reported on Monday night (April 22) around 7.30pm.
It was put out and crews confirmed there was no serious damage, and no injuries were reported.
Witnesses who were in the area at the time told Nottinghamshire Live they saw teenagers in the area, which is currently not open to the public, and police have been notified.
Pete Forster, chairman of the Friends of Wollaton Park group, who have been working on the restoration of the walled garden, responded to the incident.
He said: "Thankfully the calls to fire were made, and the services were here in the nick of time, just before the fire caught some trees.
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"I don't think the damage is too severe, but it's still worrying.
"Whoever is responsible, we've just got to find ways of engaging them in a more productive way and give them something to do.
"There are currently security cameras, but it is often hard to track people down afterwards."
A spokeswoman for Nottinghamshire Fire and Rescue service said: "A fire crew from Stapleford Fire Station were called to a fire at Wollaton Park shortly after 7:40pm last night (22 April).
"There were two areas of fire and firefighters used one hose reel and a flexi pack to deal with the incident."
A spokesman for Nottingham City Council added: "I can confirm that at 7.30pm on Monday, April 22, there was a report of a fire in the Walled Garden at Wollaton Park.
"There was no serious damage. The fire service were called and put out the fire. We have notified the police of the incident."
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