Q. Our house was built more than 45 years ago and is near a white oak tree. The oak has grown to a very large tree over the years. One massive limb, perhaps 16 inches in diameter, extends 40 feet to 50 feet over the house. At the trunk, the branch angle is roughly at an angle of 30 to 45 degrees above the horizontal. There are some dead branches and stubs where branches broke off; most looking to be 3 inches in diameter or smaller.
I imagine white oak to be a strong tree. I dont know whether the tree or branch is healthy, but I can foresee increasing possibilities of wind and ice that might cause the branch to fall.
Im hoping you might know of sources of reputable information and perhaps engineered tree surgery.
I can envision cabling this branch back to the main, vertical trunk, but would want some knowledgeable person to consider such a possibility, to propose how it might be done. We will appreciate any guidance you might think appropriate.
A. It very common to construct homes near trees. The problems begin to appear later when the tree outgrows its space and can become a safety issue. It is the reason why I recommend that no shade tree be planted any closer than 15 feet to 20 feet from the house. Massive trees such as oak should be farther away. It all has to do with doing the research to determine what the mature height and spread of the tree will be over time. Harrison Flints Landscape Plants for Eastern North America and Michael Dirrs Woody Landscape Plants are two excellent references for information about the growth rates and mature heights and spread of trees.
This is a job for a certified arborist. To find a certified arborist, call a tree service and simply ask whether they have a certified arborist that can come and evaluate the tree.
White oaks in general do have strong wood, but older trees sometimes can develop issues such as hollowed branches or trunks – die-back from being in an urban environment – or weakened because of construction around the root zone.
A certified arborist will evaluate the tree and look at how much thinning could be done to reduce to load on the tree and also look at branches with poor crotch angles (generally between zero and 45 degrees from the trunk above the branch).
Cabling is usually done as a last resort and will not solve your issues for the long term. Proper pruning and evaluation by a professional to help determine what is best for the trees health will help ensure your tree is as safe as possible. It is usually a good idea to have at least two estimates before committing.
As a final note, dont use anyone who offers to top the tree. No professional arborist would ever recommend that practice.