North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Lee, why don't you summarize the research you site so we can discuss it here?  I've read in the literature of instances of bark injury on apple trees that have been pruned and temps dropped below -25 F. within a couple weeks.  I've done extensive pruning on multiple varieties of old apples without any problem when temps around -20 followed within just a few days, but I've never worked where temps get lower then this so I only can speak of my own experience.

I should have mentioned in my post that I start with the oldest apple trees in Dec and usually don't prune any stone-fruit at all until Feb, trying to prune it as late as practical in terms of doing my rounds.  But in the process I have pruned peaches and plums preceding what I call very cold weather (we sometimes get our coldest weather in mid to late Feb.)and I've always gotten away with it.  I've also seen plenty of stone-fruit badly rubbed by bucks as late as mid-Dec and unless the trees are completely girdled they always seem to survive.  These wounds are worse than anything I'm going to do to any tree I'm pruning.  I realize the difference between anecdotal observation and research, however.  I also know that evaluating research and the scope of its meaning can be tricky and the researcher is not always the best one to do it.