I'm a bit curious as to it's classification. Isn't Canada absolutely riddled with trees? I fired up Google Earth and there's huge swaths of green where I can't so much as find a single road.

That's a fact jack. You can go 100 miles north of Montreal, start walking north and you will be lucky if you hit a logging road or a hydro line. You could walk for weeks...and you will not hit any settlement till you come to the end of the arboreal forest and start walking on muskeg.

So what counts as a "continuous forest"?

No idea. La Verendrye in Quebec is a park that is 12,589 square kilometres. And it's pretty much in the middle of the bush to begin with. Wood Buffalo in Alberta is massive ... 44,807 km2. In perspective, that is a park the size of Denmark

I note there's a link to the full paper in the article, but the implication is it's not just a definition of area, but of time. Pretty much all of the forests in North America are 'new growth'. They are not original and contiguous, and you would see big gaps and changes if you could observe a time-lapse view over the last century or two.

What's the difference between new growth and old growth. Trees are trees, right? Yeah, the rain forest being old means there's a far greater variety of plant and animal life because they've had the time to evolve. New forests only harbor species that move in. But this article doesn't get into that. The problems it brings up is that wooded areas being as patchy as a teenager's beard opens it up to erosion and loss of animal life, and the problem can be alleviated by planting new trees.

Planting new trees is definitely a good thing, but it does not replace the benefits of old growth forests. Old growth provides a level of bio-diversity and stable ecology built up over many centuries, if not millennia. Trees take a long time to grow and become forest, and it takes a lot longer for forest to become a stable and diverse ecosystem. New growth, with it's relatively homogenous flora, is particularly susceptible to disease and destruction from prolonged drought and fire- conditions that are amplified as climate changes (which, like a feedback loop, is itself amplified by the destruction of old growth forest).

Sounds like aquariums, scaled up a bit.

Still, old growth is what? 200, 500 years? Sounds like a flash in the pan.

From what I understand large parts of te Amazon and South America used to be farmland until the farmers, were, uh, disposed of ala the conquistadors etc