There used to be a very significant number of Canadian firefighting float planes based along the St. Mary's River in Sault Ste. Marie, ON back in the 80s and 90s. During the summer months the size of the fleet on hand was substantially reduced and I presume many of the aircraft were tasked with firefighting duties in the endless northern forests. I would regularly see them from the deck and pilot house of ships of which I was a crew member whenever we were passing by the Soo. Assuming nothing has changed since then, I imagine the crews assigned to those planes are being kept very busy right now battling the blazes in the Province(s).
On a related note, I saw a (smaller) fleet of very similar firefighting float planes docked on the shoreline of Inarijarvi (Inari Lake) in Finland well above the Arctic Circle when I spent the summer of 2000 bike touring and mountain climbing in the Scandinavian Arctic. Finland rivals Ontario and Quebec when it comes to having an abundance of lakes and endless forests and, given the scarcity of roads in the northern regions of those locales, firefighting float planes are obviously a very effective tool with which to battle the blazes.