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Many squirrels become unwanted tree pruners, gnawing off branches and twigs on neighborhood trees.
Ray Chavez/Bay Area News Group Archives
Many squirrels become unwanted tree pruners, gnawing off branches and twigs on neighborhood trees.
Joan Morris, Features/Animal Life columnist  for the Bay Area News Group is photographed for a Wordpress profile in Walnut Creek, Calif., on Thursday, July 28, 2016. (Anda Chu/Bay Area News Group)
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DEAR JOAN: I have a lovely, large sycamore tree in my backyard. The problem is I also have a nuisance squirrel who lives in the yard as well. It nests in a nearby tree.

This particular squirrel has recently started chewing off sycamore branches from the tree. It has stripped most of the branches of 3/8-inch diameter and smaller from a main branch of the tree. Now it is working on another main branch.

It drops six to 12 small branches from the tree each day, although yesterday it was about 15. I’m worried about the health of the tree. At this rate, it will be a bare tree. Any idea why it is doing this?

When I went to pick up all the fallen branches from the Sycamore tree this morning, I noticed that every green leaf has been removed from each small fallen branch. Only the wooden branches remain on the ground.

Bruce Wilke, Danville

DEAR BRUCE: The first thing you should know is that, depending on how large the tree is, this squirrel-led pruning isn’t likely to significantly harm it. The second thing to know is the pruning won’t go on forever.

Your arborist friend is chewing on branches for a few reasons, the most important being dental care. Squirrels and most rodents are equipped with teeth that continue to grow. They have to gnaw on things to keep those incisors from getting too long, and tree branches are a favorite dental implement.

The squirrel might also be trying to capture some moisture. We’re in a drought, as you know, and water supplies for wildlife can be in short supply, even in the middle of suburbia. The sap from the trees branches can give the squirrel a sip of water.

House construction could be a factor, too. Although it’s not mating season, squirrels are adding to their nests and building new ones. The average squirrel will have three nests — a bachelor’s pad, a nursery for newborns and a winter home. It might seem like the squirrel is not taking full advantage of the branches it’s removing, as it leaves most of them on the ground, but it might be a very discerning builder.

As for the missing leaves, these, too, can be used in nest building and also for eating and moisture.

Trying to keep a squirrel out of a large tree is almost impossible. You might try hanging sparkly objects in the tree limbs to move with the wind and cause flashes of light. Your best bet might be distraction, offering an alternative (salt block, beef bones, deer antlers) for the chewing and perhaps a dish of water to help with the thirst.

There are risks associated with putting these things out for the squirrels, as you can attract other, more intrusive wildlife.

It might be best to just let it be for now. It’s not likely the squirrel will completed denude the tree, and the pruning might benefit you in the future.

DEAR JOAN: My vet says I shouldn’t give my cat milk with her dinner. Why? I thought cats loved milk.

Janice C., San Jose

DEAR JANICE: Cats are lactose intolerant, and while they might love milk, milk does not love them. Some cats are more tolerant than others, but it can cause stomach upset, pain and diarrhea.

Have a question for Joan?

Use this form to submit questions. Photos should be mailed separately to jmorris@bayareanewsgroup.com.