We have a birch tree that has taken a turn for the worse and may be dying. I believe it was planted in 1960 when our house was built. We have had problems in recent years with a neighbor who fed the squirrels a gourmet diet. They are ground squirrels. The neighbor, who has moved, was on the other side of the yard from this tree and we have ground squirrels there, too.
The reason I think the squirrels are to blame is that most of the time when we go out the back door, they are under this tree and scoot up the birch, then jump over to one of our cypresses. You can see the damage on the cypresses where the squirrels land and hang on.
Most of the branches on our side of the birch tree have broken off from the jumping and that is where the damage began. But now the whole tree looks bad.
I don't see any other obvious problems such as sap leaking or bulges. We would like to save this tree as it provides welcome shade on the south side of our house.
Helen Jones, Sacramento
According to UC Master Gardener Liz Haines, the weight of the squirrels may have snapped some branches, resulting in dieback. However, the squirrels are probably not the main problem with your birch tree.
In the Sacramento region, the life span of a birch tree is approximately 25 to 40 years. Yours is 52 years old. Decline will often show in branch dieback or leaf drop.
The birch root system is extremely sensitive to fertilizers and herbicides including weed-and-feed products as well as mechanical damage.
Lack of water and dry soil will also cause decline. The natural habitat of birch trees is the forest where they grow alongside creeks and streams.
To determine the soil moisture, push a long screwdriver into the soil, working outward from the trunk to the drip line under the leaves. If the screwdriver does not easily penetrate the soil, then the tree must be irrigated.
Lay several lengths of soaker hoses, working outward from the trunk to the perimeter of the tree under the drip line. Attach a garden hose to the soaker hose and let the water drip for several hours until the screwdriver will easily slip into the soil.
If your tree is in a lawn, remove the grass from around the trunk out to the drip line and replace it with a layer of fine bark mulch or chopped red cedar bark. A bender board around the perimeter of the mulch will prevent the mulch from working into the lawn.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties.
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