Big Sycamore Tree... Big Problem?

Help and Advice from the Help Desk of the Master Gardeners of Contra Costa

Client's Request for Information and Advice:

I live in central Contra Costa County and have a very large Sycamore tree in my front yard. I would guess it's height at 40 to 50 feet. It has an 8 1/2 foot circumference, and many large branches have grown over my house. I am not sure how old it is, but my guess is that it is at least as old as the house, which is 65 years old. It was here when I moved in, which was 35 years ago -- and it was very large then.

The tree has received water from the lawn that surrounds it, although I am now cutting back to watering only every two weeks due to the drought, which I understand should be sufficient for the tree. It has not been pruned except occasionally to keep it out of the power lines. Large roots are visible on the surface of the lawn. I believe the only fertilizer it has received would have been when the lawn was fertilized, which hasn't occurred for probably ten years.

Sycamore tree branches over roof

My question concerns the branches that are growing over my house. Are Sycamores of this size safe growing over a house, or should I have those branches pruned back?

I hesitate to contact a tree pruner, as I am not confident that they would give me an accurate, unbiased answer since it would be in their interest to suggest that pruning was necessary.

MGCC's Help Desk Response:
Thank you for contacting the Master Gardener Help Desk.

You are right to be concerned about your tree, especially during the drought. Trees on residential properties can add value to the property, provide a pleasant setting for the house, neighborhood and community, shade from the hot summer sun, and a “sense of place”. There would no doubt be different neighborhoods without our trees. Because of these factors, homeowners taking good care of their trees are usually amply rewarded.

Your Sycamore tree is probably a California Sycamore (Platanus racemosa), a widely planted residential tree for its beauty and shade which can live for over 150 years. While generally easy to get along with, Sycamores do have their problems at times, namely Anthracnose and Powdery Mildew (see http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/sycamore.html). Overall though these are usually minor irritants to the homeowner if the tree is properly cared for, e.g. watering to maintain its health, and some pruning to provide for appropriate growth.

However, our research find that Sycamores are known to experience a phenomenon called "Summer Branch Drop". More information about this phenomenon can be found at this link from the Journal of Arboriculture. (http://bit.ly/1HormZb) 

While Master Gardeners can provide advice and appropriate references on the care of your Sycamore, we are not professional arborists, especially for significant concerns such as yours. From the pictures of the overhanging branches, it would seem that an assessment of the health and well-being of your Sycamore by a professional arborist is appropriate. While the cost of professional consultation is not insubstantial, the payback in peace-of-mind and protection of your investment in the tree and house could be substantial. So, in spite of your misgivings about the motivations of a tree service company, we would strongly advise that you have your tree inspected and evaluated by a certified arborist, probably a consulting arborist to provide a neutral 3^rd party evaluation. Certification of arborists is by the International Society of Arborists (ISA). Some certified arborists are independent consultants while others are associated with specific tree care companies. While the independent consultant's consultation is probably close to a given fee, you should be able to request an estimate from any tree maintenance company for their proposed work. UC provides some advice on dealing with contractors and consultants at this link (http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74125.html).

ISA Certified Arborists in our area  can be found at this link http://www.isa-arbor.com/findanarborist/findanarborist.aspx. Once on line at the ISA page, to find an arborist in our area, use the Search by location function. Choose United States from the pull down menu, then type in the zip code and radius of interest (25 miles should be more than ample) and search again. This will bring up a list of certified arborists who work in our area as well as distinguishing who that are associated with and/or an independent consultant.  My search found that there are many certified arborists to choose from in our area.

It appears that the tree has been receiving reasonable cultural care. Fertilizing established trees is usually not necessary. Your watering schedule may be sufficient, but we recommend that you speak with the arborist about caring for your tree during the drought as well, especially since you have exposed roots.

I hope that this information is helpful. Please do not hesitate to contact us again if you need further assistance.

Help Desk of the Master Gardeners of Contra Costa

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Note: The  Master Gardeners of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/

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