A week of 50 degree weather has New Yorkers talking about spring, but I say they're tempting fate. Or at least pushing their luck with Mother Nature. It's still 11 days till spring officially begins, and it's not unusual for April storms to dump a load of snow just when we've let down our guard. It's often these late storms that bring the heaviest snows, and those can do the most damage to trees and shrubs.
So what can you do?
First, anytime there's a build-up (6 inches or more) of snow on a tree or shrub, go outside and shake it off. Six inches of heavy, wet snow can split a shrub or tree open. It may break the crown of the plant, splitting the woody stems, or it may simply bend the branches out of shape. Even the latter can severely disfigure a tree or shrub and require pruning or cabling to resume its original shape. Evergreens suffer most from this kind of damage since their foliage helps catch and hold the snow.
Deciduous trees are vulnerable, too. Acute branch angles are weaker than branch angles of 90 degrees. Tree branches are strong, but as a general rule damage occurs when the weight of snow or ice exceeds 40 times the weight of the branch itself. (No, I don't expect you to go outside and weigh the snow.) Some pre-snow, preventative pruning to remove highly acute branch angles (less than 45 degrees) will strengthen the overall structure of your tree and leave it less vulnerable to this kind of damage.
And finally, shallow-rooted trees can be pulled over by the weight of wet snow. This isn't something you can treat retroactively, but by making sure your trees are well and deeply watered, you'll encourage the development of deep roots that provide adequate anchorage. Twenty inches of wet snow was more than the shallow roots of this poor conifer could handle. Pulled those roots rights out of the ground. It hurts just to look at it.