Coast Live Oak (Quercus agrifolia) dying in Los Angeles

Tepary

My Coast Live Oak has seemingly been dying a slow death for the past four or five years. Each year, more and more leaves seem to be drying up. I have taken some photos of the tree and leaves and posted them here. The tree has been at the top of a hillside ever since I can remember (about 42 years) and I would hate to lose it. I live in the Brentwood area of Los Angeles about two miles from Santa Monica. I can see the ocean from our hillside (altitude about 600 feet).

Any advice will be greatly appreciated!

Thanks.

-Robert












Not sure what I did wrong in this post.

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second-gen_monkey

is that scat (poo) on the underside of the leaf? or did you get that from the floor?

i think you have a bug problem. couldn't tell you what kind though, sorry.

now that you got the pics though, one of the other guys on here should get it pretty quick.

Tepary

All photos are of leaves that are hanging on the tree. I can take a closer shot of the underside of the leaf if that will help identify the disease/insect.

Thanks for your reply.

Jeffrey Lovstrom

Get a certified arborist out there to check for GSOB (golden spotted oak borer). You are in the range of concern for this.
Jeff

Tepary

Thank you but they want to charge very big bucks for just coming over. Is there any way I could photograph "telltale" spots on the tree that would identify GSOB?

-Robert

Tepary

I forgot to ask. The oak tree is up against a large pine tree. The two are competing for space and are actually touching each other. The dead leaves on the oak are worse next to the pine. Could that have a bearing on the oak problem?

second-gen_monkey

t'was my thought but i can't see any bark damage in the pics and didn't want to throw a wag (wild ass guess) out there.

tepary, if you can locate the beatle's burrow (a tiny hole on the twigs or branches) and hold a cigarette or smouldering paper near the entrance you may be able to choke out one of the little suckers for a positive identification.
you'r looking for a small larva coming from the hole. white-ish yellow with a large head with two small pin-like mblack mouthparts. might look a little flat. 3mm wide by about 20mm long.

actually here's a site that has good pics.

CISR: The Goldspotted Oak Borer

Jeffrey Lovstrom

The exit hole on the trunk will be shaped like the letter 'D'.
Jeff

Tepary

Thanks. I inspected from the ground up to about seven feet off the ground and didn't see anything like a hole. I was a teenage entomologist so I am familiar with beetle larvae. I have embedded several more photos of the tree and some close shots of a few different leaves. Hopefully someone here might see something suspicious.
Thank you both for your help.

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Jeffrey Lovstrom

Dude, I see a big problem at the base of the tree. Did you change anything lately? Did you raise the soil around it. I don't see a flare, You need to dig down and find the root flare. It looks like a pole in the ground, any mushrooms around?
Jeff

Tepary

The tree is right at the edge of a hillside. About six weeks ago I filled in dirt on the lower side of the trunk by building a small retaining wall. There are no mushrooms around the base but the soil is a little on the damp side. The dead leaf problem has been going on for more than two years, though.

When it stops raining I will take a photo from down the hill looking up at the oak tree to show the base of the tree on the lower side.
-Robert

Jeffrey Lovstrom

I think you need to get Drainage back in play. I would do it before I see mushrooms, tho. That tree is getting drowned. Get that planter bed wood out of there.
Jeff
Pull some soil away from the base.

Jeffrey Lovstrom

Start here and go in reverse. If you think about it, the tree will be fine if you leave it alone and don't make changes.
I cannot believe you cannot get an arborist out there to look at it without spending big bucks. Maybe you did not try too hard, they are out there.
Jeff

Brent Ferris

Usually smaller companies will come out for nominal charge or free; big companies like to charge.

And there is some root flare Jeff - it wouldn't cause the insect problem, just exacerbate it.

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