Need advice: concrete patio too close to a large tree

[phil2006]

Hello,

We recently hired a contractor to install a new concrete patio, but I think the patio is too close to an existing tree (it is basically touching the trunk), and I'm hoping someone here can provide some advice.

While installing the patio, we added dirt to the area surrounding the tree, in order to raise the level of the concrete patio. The idea was to create a "step up", so that the concrete wouldn't be poured as close (vertically) to the roots, and therefore the roots would be less likely to break the patio if they continued to grow (although they may not be growing anymore - this is a very large and very old tree). Basically, the natural level of the tree is more in line with the lower section of the patio, rather than the upper section where the concrete is currently surrounding the tree. Hope that makes sense.

So, while we did consider the potential impact of the tree on the patio, we didn't necessarily consider the impact of the patio on the tree. I didn't know that putting concrete so close to the tree could harm it or even kill it, so I'm looking for any possible suggestions for preserving the tree.

I've attached some photos below that illustrate:
- the front of the tree, and how it's now surrounded by concrete
- the back of the tree, and how it supports a load (along with the nearby retaining wall). There is no concrete on that side of the wall.
- the type of leaves the tree has (photo taken in summer before leaves fell off)
- the general landscape and size of the patio
- the "step up" in the patio described above
- a photo from the day before the concrete was poured, showing the preparation of the area and the "step up"

I'm hoping someone can help me with:
1) Can anyone tell me what type / species of tree this is based on the photos?
2) If left unchanged, is the current situation detrimental to the tree's health?
3) If so, then is it too late to fix it? Has the damage been done already? The concrete was poured on 11/10/2020.
4) If not too late, then what can be done? Having just installed this patio, we obviously don't want to remove the entire thing. Would removing the concrete within 5 feet or so of the tree and replacing it with gravel help?

Thank you for your help, sincerely appreciated.

 

[benjo75]

That's a bad situation. The tree will probably start to decline. The roots don't like to be covered up. They need air and water. The concrete is already set. Best case is the roots start breaking the concrete very soon. If I wanted to save the tree I'd remove enough concrete to give the tree some room.

 

[Raintree]

Looks like a white oak, not all pics are viewable. Hire an arborist to visit and assess. Removing concrete from root collar and compensating for feeder root system loss should be focus. Expect to see upper canopy decline in 2 to 4 years. Mature oaks don't take well to construction damage.

 

[phil2006]

That's a bad situation. The tree will probably start to decline. The roots don't like to be covered up. They need air and water. The concrete is already set. Best case is the roots start breaking the concrete very soon. If I wanted to save the tree I'd remove enough concrete to give the tree some room.

Thanks for your reply. When you say "remove enough concrete to give the tree some room" - any idea how much space is needed? Would 5 feet suffice? And can it be covered in gravel?

 

[phil2006]

Looks like a white oak, not all pics are viewable. Hire an arborist to visit and assess. Removing concrete from root collar and compensating for feeder root system loss should be focus. Expect to see upper canopy decline in 2 to 4 years. Mature oaks don't take well to construction damage.

Thank you for responding.

Does that fact that it's a white oak help? I understand those are more durable trees.

Do you think it's too late to do anything about it, now that the concrete has been there for about 6 weeks? Is the damage done and the upper canopy decline will happen regardless of what I do next? In other words - should I save the $ I would spend repairing the concrete for cutting the tree down in a few years?

And when you say "remove concrete from the collar and compensate for feeder root system loss" - what do you mean by that exactly? I'm thinking of removing the concrete within a 5 foot radius of the tree, and replacing it with gravel. Would that suffice?

Thanks for your help, and I've fixed the photos that weren't working earlier.

 

[benjo75]

Like Raintree said get an arborist to look at it. I don't think 5 ft would help much but it would be better than nothing.

 

[MacAttack]

Based on my old tree service days, that concrete would likely kill the tree unfortunately. Like others said, covering the roots is bad. I know it's too late now but if you were dead set on having a concrete patio there, you should have removed the tree and stump.

 

[jerrycmorrow]

Rule of thumb is don’t seal the ground or pave the surface within the drip line. Also, don’t add more than 6” of soil on top the roots every year. Get an arborist

 

[phil2006]

Like Raintree said get an arborist to look at it. I don't think 5 ft would help much but it would be better than nothing.

Thanks. If 5 feet wouldn’t help much, how many feet do you think would? And do you think the damage is already done after 6-7 weeks, or can it still be fixed?

 

[phil2006]

Based on my old tree service days, that concrete would likely kill the tree unfortunately. Like others said, covering the roots is bad. I know it's too late now but if you were dead set on having a concrete patio there, you should have removed the tree and stump.

Thanks. What’s the benefit to having removed the tree first vs seeing how it does now (hoping for the best but understanding it likely won’t do well), and then removing the tree if and when it becomes unhealthy?

 

[benjo75]

It probably hasn't done too much damage since it's winter and the tree is dormant. Unless they damaged the roots by cutting them. Soil compaction could be an issue. In your last pic, the entire root system looks to be covered. I've seen oaks live with concrete all around them but it's very rare. It's hard to say exactly how many feet of concrete need to go but the more the better. Assuming your really want the tree to live. If you don't mind either way then wait and see how it reacts. Once it starts to decline it will probably go ahead and die though.

 

[ElevatorGuy]

It shocks me how stupid some people are. Why didn’t you remove the tree prior to the patio installation?

 

[benjo75]

I've done things I shouldn't have done while when it's something out of my specialty. As arborists we're constantly on the lookout for trees and things that can help and hurt them. I've planned my house and all my shops around my trees. But if I were to start working on someone's airplane, the mechanic would come by and run me off. Doesn't mean I'm stupid. Just out of my element a bit.

 

[MacAttack]

Thanks. What’s the benefit to having removed the tree first vs seeing how it does now (hoping for the best but understanding it likely won’t do well), and then removing the tree if and when it becomes unhealthy?

It's a tough situation because not everyone is an arborist that would automatically think "hey Id better consider whether this project will kill this tree", and concrete guys are certainly not generally tree experts. If it were me, I would have known from past experience that a concrete pad would kill it eventually, removed the tree and stump, and then avoid having a dead tree to remove. Not trying to be insulting or anything, I saw this situation many many times, trees surrounded by blacktop in a paved driveway etc. We'd charge them thousands for pruning deadwood, fertilizing, injections, and then eventually charge them more money to cut it down. If your tree dies you'll have a hole in your patio and it will be impossible to remove the stump without destroying the concrete around it. Maybe you'll be lucky and the tree will hang in there.

 

[phil2006]

It's a tough situation because not everyone is an arborist that would automatically think "hey Id better consider whether this project will kill this tree", and concrete guys are certainly not generally tree experts. If it were me, I would have known from past experience that a concrete pad would kill it eventually, removed the tree and stump, and then avoid having a dead tree to remove. Not trying to be insulting or anything, I saw this situation many many times, trees surrounded by blacktop in a paved driveway etc. We'd charge them thousands for pruning deadwood, fertilizing, injections, and then eventually charge them more money to cut it down. If your tree dies you'll have a hole in your patio and it will be impossible to remove the stump without destroying the concrete around it. Maybe you'll be lucky and the tree will hang in there.

Understood, and I didn’t take it as insulting, was just curious is all. I’ll do what I can now to mitigate the damage, and if the tree does die, hopefully we can find a way to convert the stump into a bench or something so there isn’t a gap in the concrete.

I wanted to have the best of both worlds - the tree and the patio - and admittedly wasn’t educated on the impact to the tree. Will do what I can to save it, but if that doesn’t work will have to cut it down.

Thanks for your help

 

[phil2006]

Thank you all for your help so far. Spoke to the contractor and he’ll come back out on Thursday and cut away a 7’ radius around the tree. Will also call around tomorrow and see if I can get an arborist to come out before the contractor gets here.

a few more questions if you guys don’t mind..

1) anything specific I should be asking the arborist? I’ll try to have one come out and give a general opinion regardless, but at this point the only thing I can think of that would change the course of action is “don’t bother, it’s already dying”.

2) once the concrete is removed, any recommendations for how to fill the space? The patio is 4” thick, and I was thinking landscaping fabric + 2” of mulch + 2” of gravel. Is that a good idea or is there a better alternative for the tree to get what it needs?

3) as I monitor the tree’s health over the years, any suggestions on what to look for? Obviously a lack of leaves on the branches is one thing, but any additional signs would be helpful

...in the event that it can’t be saved, I would be bummed - my wife and I do like the tree. We would likely try to keep the stump and convert it to a bench and figure out a way to make it look nice. Hopefully it doesn’t come to that.

thanks again for all the help

 

[MacAttack]

Since the tree is there and you'd like to save it, and the patio is already there, Id ask the arborist their opinion on the best way to try to get water and nutrients to the root system. I have no experience in something like that, but perhaps some type of irrigation and nutrient boosting with fertilizer injections in the ground and / or tree itself.
Let us know what he says and good luck!

 

[JTM]

Out of curiosity, what are those holes for before the concrete was poured? Also, good luck. I’m surprised that the concrete guy even did this.

 

[phil2006]

Out of curiosity, what are those holes for before the concrete was poured? Also, good luck. I’m surprised that the concrete guy even did this.

Most of the holes are there because the edge of the patio is on a very steep hill, and there was concern there wasn’t enough load-bearing soil there. So, a small retaining wall was built along the
to fix that, and these holes were also dug as an additional measure - I assume so that to more of the weight of the concrete slab would be away from the edge of the hill.

Interestingly, we got estimates from a lot of contractors (some big expensive companies and some smaller shops), and pretty much all had the same approach for the hill / slope (retaining wall + holes).

And...not a single one mentioned anything about not being able to get close to the tree. Perhaps one of the others would have brought that up during the actual project (obviously the company we chose didn’t), but none brought it up during the estimate phase.

 

[ElevatorGuy]

Of course they said nothing about the tree, They wanted to sell you a patio. The tree removal cost will go up now due to the patio being in the way of the landing zone. I doubt the tree lives no matter what you do at this point. Once it dies and starts to decay underground the patio is going to crack around the base of the tree.