A couple thoughts on how having a few tricks in your wedging knowledge toolbox can really help.
1) Carry and occasionally use a metal wedge. It will drive and convert a lean more powerfully than any plastic wedge. You do have to have the discipline to keep your chain away from your wedge. But you absolutely should be doing that anyway.
2) Have two types of plastic wedges. Soft ones work well in cold weather. Hard ones that break easily in the cold work well on warmer days.
3) Spend a little more and get some plastic wedges that have a metal reinforcement on their butt, they'll last a fair bit longer.
4) When stacking wedges, don't put them directly on top of each other. They will drive easier and in some cases it’s the only way they'll continue to lift if you angle them about 70 degrees. When lifting like this, the decreased friction from less contact aids significantly.
5) Don't limit yourself to one technique, or deny yourself another technique. If a game of logging thing comes your way, consider it thoughtfully. But don't lock into anyone’s 'my way' when you can utilize another way advantageously.
For instance, does "the theory is that each size wedge provides a given amount of lift to overcome lean" have merit? As a basis to start from, yes. And if you don't have that tool bag of knowledge full, you can usually get by. But understand that there is more to life and that how you use that wedge, what type of wedge etc make the "given amount of lift" a substantial variable, (which is of course; physics).
On the West Coast, with larger diameter trees, the need for a cutting technique that better lends itself to wedging, use of jacks and so forth, the game of logging hasn't caught on.
Did I mention on smaller diameter trees that because of their size are difficult to wedge, using a back cut first, then securing your wedge(s), then the face cut without jeopardizing holding wood, then driving the tree over?
And another big caveat for all of this, what is the weight of the tree/snag you're dropping? No substitute for experience, eh? (I speak Canadian, eh).
