While we haven’t had much snow again this winter, I want to forewarn you of a post snowstorm practice that is unsafe for you and your trees. I’m talking about knocking snow off the evergreen trees and shrubs in your yard.
As I drive around after snowstorms, and see people doing this, I’m always tempted to get out of my truck and warn them that this practice is not a good one. Instead, I’ll use this forum to sound the warning.
Some people use their hands to shake branches. Others sweep the snow off with brooms. The real scary practice is whacking the branches with a snow shovel.
Nature built evergreen trees (technically conifers) to carry heavy snow loads. Their soft wood is much more resilient than hardwoods. That’s why hardwoods lose their leaves in winter – to lighten the weight on their branches and discourage snow from sticking.
Notice the shape of your evergreens. They are cone shaped. While snow build up may cause the branches to droop more than they normally do, they will spring right back when the snow melts and the added weight is removed. As it melts, the snow slides off the branches naturally, just as it does in the woods.
If you try to help evergreens shed snow faster, branches are apt to break when they snap back into place, rather than returning to their natural shape gradually. Also, your shaking, sweeping and beating action can cause an avalanche of snow to fall on you.
Removing ice can also cause injury to you, as well as damage to the tree. Ice falling from the upper branches can injure you as you stand under the branches. The stress to branches from removing ice can also cause them to crack internally. This is called radial cracking, and was quite widespread in Rochester after the 1991 ice storm. When you look at a branch cross section, it will look like a sliced pie. Cracks radiate out from the center but never reach the edge or the bark.
The next time you feel sorry for that poor, snow-covered evergreen in your yard, remember how nature designed it. Watch the snow gradually melt and slide from its branches and the branches return to their natural positions. It can actually be relaxing.