For tree wood, I had a B&D one which lasted quite a while, but I bent it when a branch bound while I was in an awkward position. I bought a replacement, and its still going strong. This blade is queued up for my next replacement. These are for cutting green wood. Try wood they kinda stink.
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When I am just cutting up tree wood for trash or firewood, I just use a demo blade. I am often cutting eucalyptus, so it ranks right up there with wood with nails on the blade destruction factor.
The true pruning one is when I need quality pruning work with a clean cut, on the tree.
One thing that is important is clearing the gullets. You are only getting 3/4" - 1-1/4" of blade travel, so the teeth in the middle of the cut are full of sawdust, and not doing much. By employing a gently sawing motion into the sawzall, you will get much better cutting results, IMO.