Shelters are vastly overrated, that's what I say. No, I'm serious. Sure, in some cases they may be lifesavers. But in those cases, you've already screwed up, big time. If you've really brought the clothes you should have brought, then you won't even need any shelter or even a fire, except for hurricanes and such lovely surprises, in which case a debris shelter is pretty unlikely to help you. To find reasonable shelter in northern forests, there is no need for chopping stuff apart. Finding a decent shelter under low-hanging branches is typically very easy, and with minimal work that can be done without any tools save your two hands, can be turned into a pretty damn windproof and waterproof shelter from the elements. One doesn't need chainsaws or even big chopping knives for shelter building. Actually, not even any knives. And as said, shelter building should be unnecessary in the first place unless you've screwed up. Don't screw up. But yeah, it's certainly good to practice all kinds of stuff in case you do screw up. In those cases, on the other hand, it's particularly important to consider one's actions carefully. Not much point in wasting time and energy on building a huge and cumbersome shelter when near equal or even better shelter could be found with much less work and risk of injury.