Winter can be very hard on the trees in your landscape.  Heavy snow and ice, especially when accompanied by strong winds, may break limbs or uproot your trees.  Road salts may also contribute to the damage.  Although you might not be able to eliminate the destruction, there are things that can be done to reduce the risks.

Young trees should be properly pruned as they grow to ensure a sturdy branch structure.  The idea is to develop the weight distribution evenly over the center of the main trunk.  You want to avoid large, heavy, horizontal branches, with unsound crotches, especially those with a ‘V’ shape.  As with mature trees, weak and crossing branches should be cut off. 

Large trees may require proper pruning as well.  Sizeable, thick canopies might need to be thinned. Some trees may require their weak branches to be cabled to enhance their structure and safety. 

Trees are stabilized by their root systems.  Therefore, it is important that you take care not to damage or cut the supporting roots.  Smaller ones with under developed root systems may need to be temporarily guyed.  Additionally, don't allow soil to become compacted  and thereby cutting off nutrients, oxygen and water.

Not all winter tree damage can be prevented.  If your tree has sustained dangerous broken or hanging branches, they should be removed as soon as possible, before they cause more harm.  The idea is to stop them from ripping down the trunk of the tree, resulting in a larger wound.

Heavy snow may be dislodged from branches by gently lifting them up with a hard rake or pole.  If the forecast is calling for a period of above freezing weather, you may be able to just let the snow and ice melt -definitely the easier solution.

Road salt can cause considerable damage to trees, especially white pines and sugar maples and other species.  Calcium chloride and sodium chloride (rock salt) damage roots as they leach into the soil. It also injures leaves (or needles) when sprayed up by passing cars and trucks. Washing salt off the leaves with a hose may help.  If the drainage is good, you can leach out the salt deposits with heavy watering when temperatures get above freezing. 

As a preventative measure, you can plant trees that are more salt tolerant.  Very tolerant species include red cedar, red and white oak, and black cherry.  White ash, black locust, and black, yellow and white birch are also considered to be tolerant.   Encourage local officials to use a more benign mixture with a heavier concentration of sand or grit than salt.