Care of large oak trees

Mashara

We inherited a dozen large oak trees when we bought our house. I think the previous homeowners had a service come out to fertilize them once a year. My husband was thinking of contacting an arborist for them.

I was wondering how you care for your large trees and how much you budget annually. Also, I'm really up in the air over whether we need an actual arborist or whether the tree service would be sufficient. After all, these trees were here before the house was built and have survived to us. That said, three trees across the street have lost decent size limbs (15-30 feet) the last two summers. 

Oh yeah, here's a pic of the base of one:

 

~NB~

Since I am a Certified Arborist, I monitor the health of my own trees. Would I trust a "tree service" to do this? NO. I wouldn't expect a tree service to be competent to offer health and diagnostic services at all, I wouldn't trust them to be competent to perform structural pruning. I value education, and I don't give anyone who identifies her/himself as a "tree service" much credit. IMO, if they were educated, or had the required knowledge, why wouldn't they pass the test to be Certified?

I would trust a "tree service" to cut up a tree after it had fallen down, or to grind up a stump, and to clean up the debris, only because those things don't require any specialized knowledge beyond operating the machines. Because of that, I'd also expect them to be less expensive than a Certified Arborist.

I'd try to contact the previous owners and ask them for the name of the Arborist they used, and what type of services she/he performed for the them. I'd ask if they had asked for the tree to be fertilized, or did so at the recommendation of the Arborist. Personally, I don't feel fertilization is an essential service for a mature shade tree, but I do feel that a thorough risk evaluation is, and that it should be done ASAP. If the Consulting Arborist (a specialized segment of arboriculture) finds decay in large scaffold limbs, she/he will recommend cabling or pruning (Consulting Arborists may or may not perform those services). Ideally, you'd hire a Registered Consulting Arborist who would climb the tree to examine it (once again, not all Arborists or RCAs are qualified as tree climbers). You would also turn to a Consulting Arborist to appraise the trees, in case you did have a limb failure and property damage down the road. If the appraisal is higher than $500 (and it will be), you should carefully read your homeowners insurance policy to find out if tree failures are covered for more than that... if they aren't (and most of the time they aren't) you should have the trees insured.

For diagnostics, preservation, health care, structural pruning, risk assessment, and appraisal, the bare minimum qualification I'd require is CA. It would be the starting point. After that I would make sure she/he had all the specialized training necessary in the areas I mentioned.

http://www.asca-consultants.org/directory/search_Results.cfm

 

TarHeels&Rebels

Not that my opinion's really necessary after NB's, but...

Tree services are jokes.  Like she said, ONLY use them to cut down fallen trees or stumps.  Most of them have zero education and routinely recommend horrible practices like tree topping.

I've never heard of mature trees being fertilized or really needing any care if they're in good health.  

Mashara

Thank you  both so much for your replies. I rarely frequent this board and forgot to check back soon! Anyway, the previous homeowners didn't use an arborist but paid a tree service to fertilize the trees annually. I'm reassured that they might not need that kind of routine but will look into having the trees assessed. Thanks!