Sioux Lookout.
On a second reading, I find the MNR's public description for its Twin Otter rather curious.
"The DHC-6 Twin Otter is equipped with tundra tires so it can land and take off from anywhere, making it useful for services where airports are not available"
I can't say I've ever seen a MNR aircraft equipped with what I would call "tundra tires". Besides, since most of northern Ontario is either forest, boreal or water, I'm not sure where they would intend to land that isn't at least a gravel runway.
"Each of our six aircraft can also be outfitted with water tanks to assist in wildland fire suppression"
I think every one I've seen has had amphibious floats, and I don't know if amphibious+water tank floats is a thing. Since moving their main maintenance centre from the river-based location to SSM airport, I imagine most if not all of their fixed wing fleet is amphibious.