The winter of 2014-15 was far from benign, but trees fared quite well. That’s because we didn’t have any really heavy wind or ice storms, which can wreak havoc with trees.
Also, we didn’t have constant temperature fluctuations. Rather it got cold and stayed that way, which is good for trees. Contrary to popular belief, it isn’t the extreme cold that causes tree damage. It’s the changes from cold to warm and back. Extended warm spells are especially bad for trees. They think that the warmth is here to stay and may begin to break dormancy. Then the weather turns cold again and they’re “confused.” The only way continual cold weather all through the winter will harm your trees is if they aren’t hardy in our zone 5-6 climate, or if you’ve planted them on the windward side of your house and they don’t like wind, of if they’re in the shade and they like full sun. In these cases, they were stressed before winter ever started.
Have you checked around the base of trees for girdling by rabbits, mice and other animals? This would’ve been the ideal winter for this to happen. Mice like to eat in private and the amount and duration of snow cover afforded them the opportunity to do just that. Rabbits, on the other hand, dine out in the open above the snow. As a result, trees can suffer from both of these varmints.
It’s bad any time animals feast on your valuable trees. When they eat all the way around a tree, however, the tree is usually doomed. The rodents eat the bark and the tender, tasty layers beneath the bark. These are also the layers that contain most of the tree’s vascular system for transporting water and nutrients up the tree and for transporting food back down to the roots. There is an expensive surgical procedure, called a bridge graft, in which small twigs are grafted all the way around the tree’s circumference to bridge the girdle. Your tree has to be extremely valuable to justify this investment.
Anything I tell you now is like closing the barn door after the horse escapes. But, you can tuck these ideas away for fall when you’re getting ready for next winter. First, be sure you don’t have mulch volcanoes or any mulch right up against the trunk. Be sure there’s no high grass growing close to the trunk. Finally, wrap the trunk in screening or hardware cloth from the base to about a foot above the typical high point of the snow. In summer, be sure to remove this protection to allow the trunk to grow.
Some other problems, which I’ve written about before, include frost cracks caused by temperature fluctuations, winter burn on evergreens caused by desiccation, and salt damage affecting trees planted too close to salt treated roadways, driveways and walkways. Another problem is sunscald, which is actually a canker caused by temperature fluctuations and affecting the trunk. Spring freezes can cause a similar problem that affects the new foliage, and freezing can also damage the roots of some species.
As winter wanes and spring returns, inspecting your woody plants can be one of your first “green thumb” tasks for the new season. If you find any of the problems described above, or any not described above, please call us for a professional evaluation with recommendations for remedying the situation.