When the trees are bare and leafless in the middle of winter, it's a good time to analyze them for structure, safety, center of gravity, health and flowering. Then decide what pruning you want to do ... but do it when it's the right time of year. Not now.
Look for the following things
1. Is the tree healthy? How you can tell is by looking at the branches to see if many are dead, broken off, and have twig sprouts below dead areas. Healthy branches have twiggy ends with many buds on them.
2. Are there big cavities? Do squirrels live inside the trees? A worrisome sign.
3. Is the tree well balanced? Does it have a good center of gravity? Or is it too heavy on one side, particularly if that side could fall onto the house in a bad wind or ice storm? Also, are some of the branches so much too long that they might break and fall (even if the tree is well balanced)?
4. Is the tree "V" shaped? V crotches in main trunks are generally considered less safe than a single trunk. Sometimes they are wired together to prevent them splitting. The latest theory is that if the diameter of the smaller trunk is greater than 60 percent of the diameter of the main trunk, it is weak. Ditto if there is a crack between them.
5. Would some of the smaller trees, especially flowering trees, be more esthetic and sturdier if some overly long branches were trimmed back and shaped? Also, what if crossing, rubbing or awkward branches were removed? What about branches hitting the house or garage? The central scaffold of the tree that you see now will become its main shape as it grows.
When is the right time to prune trees?
It depends on why you are pruning. For safety and hazard trees, do it as soon as possible. For shaping and improving the tree's future growth, do it in late winter or early spring. Except for "bleeder" varieties, which are trees that drip sap from early spring cuts. These are mostly birches and maples (That's how we get maple sugar.) Most sources say it doesn't really hurt them, but it is disconcerting to see a cut end dripping sap.
To enhance flowering, each species of tree has special requirements. In general, pruning is done after flowering. To increase fruiting, involves the wisdom of the ages. Many books have been written about this, and the old ones are the most detailed.
Summer pruning is usually done to slow growth and keep a tree within the bounds of its space. Early fall pruning is similar to early spring, but "bleeders" are done here.
If this sounds like more than one can know, welcome to the club!
There are trained tree professionals (preferably professional foresters and certified arborists) who know a lot, and consulting them is worthwhile. They are expensive. They should have insurance and wear safety gear. Don't hesitate to ask about these. A guy with a power saw can do a lot of damage if he doesn't know what he's doing.
Needless to say, power saws are dangerous and a homeowner with a power saw can seriously hurt himself, as well.
So look to your trees in winter and decide what needs to be done. Safely.
Ruth S. Foster is a landscape consultant and arborist. More gardening information can be found on her Web site: www.mothersgarden.net.
author: Ruth S. Foster