About 35 years ago, my husband and I invested in a treatment centre for abused teens. It was located on 50 acres of scrub pine forest an hour or so west of Toronto. When we were looking into the opportunity, hubby and I tried to trek through the forest to explore the property. We thought it would be a good idea to at least walk the perimeter and see what we were purchasing. We made it about thirty feet.
You see, it wasn't just densely planted. Fallen trees, thick underbrush, and large areas of knee-deep swamp prevented us from making any progress. It was also disorienting, because once in amongst the trees, we couldn't see the sun, and we worried about walking in circles. Not to mention being eaten alive by mosquitoes. We gave up and turned back, and in the months we lived there, we never did manage to go any deeper into the forest than that.
One day some men with rifles knocked on the door of our log cabin and told us to keep the kids inside, because they were going to hunt wolves on our property. Yes, wolves.
This was only 50 acres of new-growth forest, not old, within a short drive of Canada's biggest city. Canada has about 912,000,000 acres of forest (1,389,968 square miles). Most of it is just as impenetrable or more so, inaccessible by any roads. Stats Canada says 66% of Canadians live within 62 miles of the U.S. border on the south. There's a reason for that, and it's not just the black flies.
My son used to live at the literal end of the road in northern Manitoba. Any intrepid people who live further north have to fly in, and the season and weather can isolate them completely for periods of time. Vast tracts of Canada are completely uninhabited, and in fact, there are parts of the country that haven't even been mapped yet. We can get an idea of what's there from satellite imagery, but no one has set foot there.
Lightning strikes can smoulder and fires can go underground and not show up until days or weeks later.
Just pointing out the scope of the fire-fighting problem.
Also pointing out how difficult a place this would be to invade or occupy.