It's a common misconception that gardening and ground work come to a standstill in the winter. True, yard work becomes a fraction of what it is during the peak summer months, but there is work to do, and jobs like tree care can be successfully accomplished during the winter. And this work gives you a good excuse to get outside and get some exercise and fresh air. Trees experience a period of dormancy during the winter months, so this is an ideal time to do minor pruning and other small jobs. There are at least four things you can do during the winter months to ensure healthier trees, according to the International Society of Arboriculture (ISA), a nonprofit group that oversees the tree care industry and acts as an advocate for proper tree care.
Chances are that you have some bags of mulch or a bale of hay sitting in a shed or the garage. If so, spread a thin layer around the base of trees, especially young ones or those that are newly planted. Ideally, this should be done during the fall, when mulch is still readily available. But sometimes the bulk piles available at nurseries have not frozen solid or the heat of decomposition has kept them from freezing. If you haven't mulched, you might give it a try, especially if your area encounters a midwinter thaw or is experiencing a mild winter.
Remove dead or damaged branches. This assumes that you can get a firm footing (don't stand a ladder up on an icy surface).
Perform limited greenwood pruning of declining and poorly placed branches. This should be done with as minimal an amount of cutting as possible.
If your area normally experiences a mild winter or if you are experiencing a mild, dry winter where you live this year, the trees could benefit from water. Water where soils and trees are cool but not frozen and where there has been little precipitation. The ISA offers a complete set of brochures that covers many of the basic principles of tree care. Write to ISA, P.O. Box 3129, Champaign, IL 61826. The organization also has an outstanding website that offers much of the same information online. The site can also help you locate a professional arborist in your area.