Being a new climber and living in Canada I am wondering about the strength of a limb while climbing in the winter. If the sap has left and the tree is frozen does the limb loose it's strength. Would like to hear from some northern arborists. Thanks T

I've been thinking about this too, as I live in northern Minnesota (Bemidji). We don't get nearly as much snow as you probably do (nothing beats the lake effect), but we get plenty of cold.

I'm a relative neophyte at climbing, but as a forest ecologist I do a lot of reading about trees. Here's what I get out of reading Shigo, and some of the literature on cold tolerance in trees: Cold dry wood is a bit stronger, but not enough to matter, and dry wood is dead wood that we don't want to climb on anyway. Tentatively: Cold wet wood that is sound is probably not affected much by freezing, but freezing water can open up flaws in the wood and make them worse.

That's what I've been able to find in the books, but there isn't anything in the way of direct engineering testing that I've been able to dig up. In any case, I'd also like to hear what the northern arborists have to say about the matter; they're the ones who actually have to get it right in their day-to-day work. The postings about winter climbing that I can find on the arborist sites seem to be more about keeping the climbers functional (warm & dry, with reasonable manual dexterity) than about any special concerns about branch strength.

Any arborists and/or winter climbers out there who want to weigh in on this?

another note: watch out for falling clumps of snow!!!! they can knock you out or shock load your setup if its a big enough slump of cold wet snow...!!!!