A strict cordon remains in place and there is currently no public access for vehicles or walkers to Glenmore Forest Park or Loch Morlich.
Homes and businesses, including campsites and a ski resort in the Glenmore Forest Park area, have been evacuated as a safety precaution.
A “very high risk” wildfire warning remains in place across the central Highlands, eastern and southern Scotland until Friday.
Assistant chief officer Henderson added: “The conditions which contribute to wildfires remain present across large parts of Scotland.
“We urge everyone to enjoy the outdoors responsibly and do everything possible to reduce the risk of fire.
“Please do not light campfires, use disposable barbecues or have any naked flames near dry vegetation. It only takes a small spark to start a wildfire that can spread rapidly and have a significant impact on communities, wildlife and the environment.”
First Minister John Swinney paid tribute to the people tackling the wildfire in the Cairngorms during a visit to the scene.
He said: “That’s been a combined effort led by the Scottish Fire and Rescue Service, but involving land managers in the locality, involving organisations like the RSPB and the Cairngorms National Park and also Forestry and Land Scotland.
“It’s got to be a combined effort to make sure that we have the skills, the expertise and the resources to make sure such circumstances can be tackled and the great natural beauty of Scotland protected.”
