Looks like a nice tree darn it. Can you reach up there? Is it mushy?

To me it looks like an old wound which is open now. Am I correct there are structures under the tree? I believe it is time to get the tree inspected and see how rotten it is inside.

Looks like a canker of some sort. Cankers are symptoms of some type of fungal, bacterial, or other infection in the vascular cambium, such that the tree is unable to close up the wound. Cankers are areas of dead tissue.

I see those wires nearby and wonder, could they have previously been positioned such that they rubbed against the tree here constantly, and only later were replaced in the position we see here today?

In any case, you're probably going to need to have a sample taken to a plant disease diagnostic lab for positive ID. The yellowish material may be the fungus causing the canker in the first place....but it could also be a secondary infection, taking advantage of some other agent having killed tissue in that area. such trunk cankers are serious as they affect-obviously-the main stem of the plant. Get it looked at by somebody with-at a minimum-ISA certification.

Yesterday I climbed up there on a ladder. Below are 2 more closer pictures. The grayish parts are soft, and must be some sort of fungus. The second one is just a blow-up of one of the icky places. I did call our tree people (2 of whom are arborists) yesterday, and they are going to come in a week and diagnose it, and recommend a treatment. I was wondering if any of you have any further thoughts? Thanks so much for your help -

Jackie

wisconsitom - thanks so much. I will post on here again after the arborist looks at it.

Jackie

IMO, removal of that nice tree would be very premature at this point.

Yeah, I wasn't advocating for removal...just expressing concern. Cankers are serious.

Thanks for that close up!

I don't see any signs of encapsulation yet do you all?

No, and that's just it-cankers kill cambium, so this is exactly why this is a serious thing.

Update - today we had 2 arborists look at our tree. One of them climbed up the ladder with a drill to see how far into the trunk (which is about 30 inches in diameter at this point) the rotten wood went. It turned out that the first 4 inches his drill went through was all fungus (which is now sticking out from the edge of the trunk by about 3 inches), and then it went through another 8 inches of rotten wood.

They said that if we did not want to take down the tree (which they did not think was absolutely necessary, as there was so much healthy wood left), it should be "safety pruned" to take a lot of the weight off it (it is near our house), and then monitored. Interestingly, they disagreed about whether or not the fungus & dead wood should be dug out of the wound.

Any thoughts?

Oh, those wires you see in the picture cannot physically touch this spot on the tree - another branch is in the way, and the wires are even several feet away from it. Pictures do telescope distances sometimes. Both arborists thought that the original wound was caused by a large branch breaking off a long time ago.

That could be. If it broke off "wrong", that is, if the vascular cambium of the trunk itself got torn up in the process, that could start a bad decay pocket. Not entirely sure about that. In any case, I don't necessarily believe there's any benefit to scooping out the rotten stuff. There really is no connection between that material remaining there and subsequent decay. The decay organisms are there whether you see them or not.

The whole thing about whether it is or is not safe to leave the tree standing is largely your call. Sure, something could happen, but it would be my guess that you guys won't be going out and standing under it in the next tornado warning. What I mean is, a little dash of common sense can go a long way towards keeping people safe. I had an enormous silver maple in my back yard for year. True, I did eventually take it down but for literally decades, we worried about that giant thing during high winds and so on. Yet the most that ever happened was a little gutter getting bent up and one time, a limb did punch a hole through my garage roof. I don't see such occurrences as life-changing events. In fact, mostly, that's what home owner's insurance is for. good luck-it's a great tree in a great spot.

Very important -- be sure they do not "top" the tree. I've seen very good jobs of proper thinning and also disastrous "topping" jobs.

IMO, the branches below the wound need little if any thinning since their weight is supported by the trunk below the weak spot.

Jacqueline, I forgot to address the arborists' wanting to "take quite a bit of the weight off it" bit: I would definitely not recommend any amount of heavy pruning on this tree, to take weight off or for any other reason. It will do best if it is mostly left alone. A light pruning-which is not at all what it sounded to me these guys said they'd want to do-could be okay, but I would not go beyond that. And for sure, as Beng says, no topping allowed.

It's your house, your possessions, and your family living underneath that tree (if that is your house we see in the picture), so it will have to be your decision on what to do. If it were my tree and my house, I'd be seriously considering removing it before something bad happened. Your life and your family's lives are too important to take a chance.

You mentioned that the people that came out were "arborists". Were they ISA certified? Some monkeys that have figured out how to start their home-e-lite saw call themselves arborists, but they really aren't (at least not by my definition). What do you know about the expertise of the people you hired?

There's no disadvantage to scooping out the rotten wood, if it's done properly. Removing it might allow you to keep a better eye on what's happening with the tree, if you decide to keep it for a while. You wouldn't want to remove more than what is rotten, because doing so would likely encourage further damage.

Yes, they are both ISA certified, and the senior one of the two is a past President of the Calif. Arborists Assoc. Lots of other memberships in related associations, etc. The company has been in business for 38 years, and we have been using them for 20.

Also yes, the tree is huge, and not far from our house (see pics below). It is over 5-6 stories tall. Family history says it was planted in the 1930s (by my DH's grandfather), so that would make it over 80 years old. I looked up the age of trees, and it said an average age for this type of tree is 80 years, but they found one which is 180 years old.

We are getting 2 estimates - one to take down the tree, and one to do the "safety pruning" they are talking about. Fuzzling.

WInter - impossible to get the entire thing in 1 photo, it is so big - makes my 3 story house look small.

Summer a few years ago. The large evergreen eugenia tree on the right is now gone.

Nice place and nice tree. A shame about it.

If it failed there is the tree close enough to damage your residence?

No chance it is on the city's property in the easement?

Maybe I am not seeing right to scale on my cell.

Sounds like you have done your homework with picking people, then. I wouldn't consider them infallible, but at least you know they have the training and background to have a basis for their decisions and recommendations.

As Tom alluded to, I would want more information on their "safety pruning". Pay particular attention to comments about the need for ongoing followup after the initial work! They were there and we weren't, but I can't help but wonder what they have in mind and whether or not it's really a good idea.

I wish other homeowners would do as much research and put as much thought into their tree's care as you do! Around here the vast majority of people seem to get their trees topped. Almost without exception, these same trees end up falling apart within just a few years. Yet, these same people never really seem to understand that their poor decision making process was responsible for the loss of their trees.

Yeah, is that a street tree? If so, and if you live in a community with a forestry dept, etc....you might not even be on the hook for removal.

Big tree sure-our guys would have that thing down and cleaned up before lunch. But I digress: Is this tree by any chance on city (street terrace) property?

It is not a street tree. Just weird angle in the photo. It is planted on our lot about 2 feet from our lot line in one direction (next door neighbor), and about 15 feet from another one (sidewalk) in another direction. There are huge street trees on our street - 100 year old black walnuts. Our scarlet oak and one of the street tree walnut trees actually are touching their highest up branches.

Here is a picture showing our tree on the right, and the black walnut street tree on the left (and another black walnut street tree beyond that one):

Here is a picture of their high up branches touching - again, ours is on the right:

Not only branches are touching, that utility pole seem to be pretty intimate as well

Yes, the tree grew up around the utility pole (we have pictures of these trees taken in 1905, when our house was new and the trees were 7 ft tall just planted saplings). PG&E is pretty good about not harming the trees when they have to do pruning.

Jackie

I just don't know what to say at this point. "Safety pruning"...man, I've been at this for decades....and I don't know what that is. I envision a series of pruning cuts to reduce overall size of tree, something in the old days called drop-crotch pruning, which is a legitimate technique, but really, I'm not at all sure safety, let alone this tree's health, would be enhanced one itty bitty bit by doing so. I think I'd just have a "crown cleaning" and call it a day. Don't stand under the tree during tornadoes, don't place your hammock directly under that wound....and go on with life. And let the tree go on as well!

UPDATE - we got a quote from the tree company. $15k to take the tree out, or about $10k to "safety prune" it, which they said needs to be done once a year. We are getting a second opinion - an arborist from another company is coming to look at it in the beginning of April. I am not saying the first company is wrong, but we were shocked at those numbers, particularly the on-going theoretical cost of keeping it "safe".

Jackie

I agree with your sense of shock. I imagine Cali costs are probably considerably higher than what I'm used to seeing around here but that's just plain high. Even the removal cost is far higher than I would have expected.

I support your decision to seek more opinions. I would rate either of those numbers as out of the question. At that rate, I think I'd sooner live with the associated risks, which is a viable option regardless.

Thanks wisconsitom - so nice to hear that our reaction was reasonable. I'll post on here again after the next arborist looks at it.

Jackie

Yeah, that's just way too high, and like you say, with ongoing yearly costs.....it's just not reasonable. And I still don't know what their "safety pruning" consists of. I've been an arborist since 1980. Never once heard that term.

Ridiculous. At those costs, I'd simply leave the tree alone and save a fortune.

UPDATE April 16: OK, it is now 6 weeks after my first post. 6 arborists from 4 firms later (most of who did not charge for visits or opinions), the fungus has been identified (by UC Berkeley, UC Davis, and the State of CA forestry dept, - and all of the arborists agreed) as inonotus andersonii, common name "canker rot". Accd to what the arborists told me, and what I found on line, rots & kills oak trees, and can cause failure of main limbs AND TRUNKS. Drattt!

We did hire an arborist who only assesses risk - does not do tree work. He used a ressistograph to drill into the main trunk 2 feet below the wound. Found bark and sound wood the first 5 or so inches, and then hollow or rot the next 6 inches (which was as long as his fancy drill). He did a report for us and recommended that the tree be taken out. He said that, because of the area of rot, and the closeness of our next door neighbor's house, he thought if the main trunk failed the 80' tree would fall in the direction of their house,and land on and squash our neighbor's one story house. Double Drattt!

So, we are getting another bid to take out the tree. I am so unhappy - we really wanted to save that tree. We even had 2 specialist technicians from a nationwide firm who do some sort of sonic investigation of trees, and can produce pictures of cross sections of the trunk using sound, come and look at it. I asked them to give me a quote to do their fancy sonic investigation at the base of the tree (where they normally do it), and also above and below the wound. After I sent them the risk assessment arborist's report which identified the fungus, they told me it was not worth the large cost of doing their investigation, as that fungus is very very bad, and the tree was a gonner.

So, I only have one question for anyone on here who knows about this fungus (trying to make myself feel better) - is it as bad as they say in oak trees?

Thanks for all of your assistance again - this has been a real education which I would rather not have!

The only good news is that we have ANOTHER scarlet oak in the back of our property, which is sort of leaning over our fence and going above another neighbor's garage. The risk assessment arborist said it is not diseased, but recommended we take out two major limbs which are going sideways, to better distribute its weight. We are getting a big to do that too.

Jackie