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Trees can take a big hit on 'snow days'

Did you laugh at me last Friday when my column showed bluebirds (of happiness) and little spring bulbs? It was sunny and exhilarating weather that hinted at spring – and then the snow came. That’s March in these parts. It’s normal and most Western New Yorkers know how to live with it. A late snowstorm, however, does present some danger to trees, and sometimes to people.

To tap some arborist knowledge about helping our yard trees, I interviewed arborist Jared Webber about what to do right now when a great volume of heavy, wet snow has bent and burdened the branches of all kinds of trees and shrubs. Jared is the second generation arborist owning Bradley Tree and Landscaping, which was started in 1981 by his father, Rex Bradley Webber, and he cares intensely about educating consumers. We talked about what people can do to help their yard trees, as well as some things not to do.

Deciduous trees laden with snow

Some trees handle the weight of snow better than others. Plants have evolved to survive in their native habitats and climates. Jared pointed out that many of our beloved yard trees such as redbuds and Southern dogwoods were not structured to bear heavy snow loads. They have “co-dominant stems”: Their branches grow in tight V-formations. Pressure or weight on branches like that often causes a vertical crack or fracture.

Sometimes a branch breaks or splits off; other times the crack allows decay or rot to begin. A stronger branch structure is a wider-angle connection of branch to trunk, as you might see on an oak or beech tree. That branch can bear heavy snow, ice, and wind storms best.

Understanding branch structure leads to some practical suggestions:

1. Shake off the snow – carefully. Common country wisdom has always been that it might help our trees if we shake the heavy snow off the branches. I specifically remember seeing my young mother doing that, and followed the practice in my own yard (which often results in large plops of snow on one’s head).

But Jared advises: Look before you release the branches in a deciduous tree like the dogwood. “If you see a hint of a vertical fracture, make a note to call an arborist later,” he said. When the branches are again growing upright you may not see a crack starting, and a weak structure and rot inevitably follow. An arborist can install bracing or prune selectively. Early intervention prevents lots of damage.

Buds are also at risk. When branch tips are buried it’s tempting to pull them out to free them. This may be harmless under fluffy snow, but if the tips are under heavy snow or ice, pulling at them can strip off the buds. They are baby buds. Be gentle.

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2. Consider reduction pruning. Any time before leaves appear, walk around your yard and look at the trees around you. Focus on the branch structure and canopies. If your small ornamental tree (maple, redbud, dogwood, crab apple) or your ancient shade tree look solid and crowded on top, it may be time for reduction pruning. The solid canopy, especially when it’s thick with wet snow or ice, acts like a sail: Wind hits it and cracks branches or tips over the whole tree.

A professional arborist knows how to thin the branches, lightening the canopy. This is not a job for amateurs, and the larger the tree the more dangerous it can be (for the tree and for you).

My first lesson in reduction pruning came from Jared Webber’s father, Rex. After a 3-foot diameter tree fell against my house, he reviewed my other trees (some probably planted during the 1800s). A Siberian elm was planted 20 feet from the kitchen door (way too close). It’s now surrounded by a deck, and many foot-thick branches lean over my roof.

With three men and cherry-pickers the Webbers sculpted that tree canopy. The form was lightened and opened, weak branches removed. Light could enter so that new growth would be healthy. That reduction pruning probably added 50 years to the life of that tree (and maybe saved my head).

Blow-overs and other dangers

When high winds follow a heavy snowfall or ice event, many trees blow over – especially those with dense canopies or shallow roots. Mature spruce trees are typically poorly anchored so they are often victims. Jared reminded me that many blow-overs could be prevented if you can get an arborist to do proper staking or other protective measures.

I learned from personal experience: I’d planted three Serbian spruces in a windy location in clay soil near a driveway – best I could manage at the time. When they were about 20 feet tall I saw some roots pulling out of the soil. No way to stake or anchor them because of the driveway. Rex Webber put boulders on the roots to hold them down on the west (windy) side. While we know not to put weight on tree roots, this was the time to do it. Fifteen years later those Serbians are standing tall.

Here’s a serious warning for all who are tempted to un-pile tree branches or whole trees that are downed: certified arborists and tree safety professionals all have stories about people losing limbs (even a be-heading) when branches that were held down suddenly snapped back with enormous force.

Jared remembered a court case involving a 15-year-old worker who was assigned to use a chain saw on tree branches that were under tension. The branches “barber-chaired” (a term referring to the way the tree fibers twist when tension is released). The tree snapped like a rubber band, and the chain saw hit the young man’s face.

Pay attention to what’s going on with your trees. Schedule a tree check-up periodically. When you think a tree might be in trouble, call a certified professional arborist who has insurance - not a friend or relative who is a self-proclaimed expert. And be careful out there.

Recommended websites for tree care education:
TCIA (Tree Care Industry Association)

ISA (International Society of Arboriculture)

* Read Sally Cunningham's "Great Gardening" column from last week:

Bluebirds are house-shopping. Have you noticed?

Sally Cunningham is a garden writer, lecturer and consultant.

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