Editing CanVec-inspired relations is always a challenge - I mean, just look at https://www.openstreetmap.org/relation/1100815 :)
It looks like iD didn't flag anything up here (which is not entirely a surprise).
One thing that you may be able to do immediately after the edit is to check affected relations with JOSM's validator - I wrote https://www.openstreetmap.org/user/SomeoneElse/diary/406398 a few days ago in another context, but it should work here too.
There's also the more general check that was mentioned above - https://tools.geofabrik.de/osmi/?view=areas&lon=-63.76396&lat=44.62007&zoom=13&baselayer=Geofabrik%20Standard&opacity=0.95&overlays=duplicate_node%2Csingle_node_in_way%2Cduplicate_segment%2Cway_in_multiple_rings%2Cintersection%2Cintersecting_segments%2Cring_not_closed%2Ctouching_rings%2Crole_should_be_inner%2Crole_should_be_outer%2Cinner_with_same_tags%2Cways%2Cduplicate_node%2Csingle_node_in_way%2Cduplicate_segment%2Cway_in_multiple_rings%2Cintersection%2Cintersecting_segments%2Cring_not_closed%2Ctouching_rings%2Crole_should_be_inner%2Crole_should_be_outer%2Cinner_with_same_tags%2Cways .  That won't show issues immediately but it will check everything, and is also useful to do.
As for the best way to make CanVec relations "editable by humans", that's probably a question for https://community.openstreetmap.org/c/communities/ca/95 .  Where I've encountered similar things (not in Canada) I've tried to isolate bite-sized pieces of natural=wood from the monster relation and attack it that way.
That will also allow you to update OSM to match changes since CanVec was imported at https://www.openstreetmap.org/#map=20/44.6587018/-63.8351248 , that's 14 years ago.  A glance at the underlying imagery suggests that it's all either more or fewer trees, and there isn't a great correlation between "natural=wood" in OSM and "lots of trees in imagery" - there's some, but not much.
Best Regards,
Andy
 