PRUNING YOUR TREES IN WINTER
Pruning trees is always a conundrum of sorts. When is the best time to do your tree pruning? It, of course, depends on where you live and what hardiness zone your trees occupy. Since this is a blog for the North Country of New England, I'm going to assume these are the folks I'll talk to now. If you live somewhere else, refer to the Extension Office of the Land Grant University of your state (usually titled, "University of_state name_").
My personal opinion is that the best time to prune is in the winter. However, there are a few things that you have to think about before you make this decision. In mid-winter the snow may be deep; temperatures horrendous; and your spirit, unwilling.
This pruning is usually termed, "late winter pruning", but in late winter the sap is already beginning to run in trees like maples and birch (think maple syrup and birch beer. Both are tapped in February and March.) And, there are those that feel cutting hard, frozen wood can damage the cells, making it difficult for the cut areas to heal properly. Another complication is that severe pruning can cause a flush of growth the minute temperatures rise. If it's a blooming tree that may flower, and you consequently get a hard frost, you can picture the next step. The new growth will be damaged and your fruit curtailed. So, we wait until March and April.
The reason winter is a good time to prune is that you can see what needs to be done when there are no leaves on the branches. The shape of the tree becomes obvious. You can also, quickly, pick out the broken branches.
As you can see, this is not a really simple decision. I personally wait until a warm "January Thaw" type day (whether in January, February, or early March), and get my tush out there!
I have found an absolutely wonderful site at Texas A&M that explains a TON of stuff about pruning. Go to this page and LEARN!!!