# Spray foam for a cavity in a tree ??



## Dadatwins

Customer called today wanted to know if it was ok to put some expandible spray foam in a tree cavity. She is worried about bees or something making a nest in the hole. I know usually we are told to leave cavity alone but was wondering if anyone ever heard of this. Customer wanted to use foam from home depot thought it sounded almost like perfect solution but wondered about harm to tree? Have not seen tree or size of hole. Customer says its a little bigger than the size of grapefruit. Any ideas????


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## MasterBlaster

*I've never liked doing that*

I would prefer to just leave it alone. If your worried about bees/whatnot, then keep em outta there.
Chunk it full of dishwashing detergent/water mixture every other time you mow the lawn. That will cut down on critter infestation, and I don't think it hurts the tree. 

What say you, GM?


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## OutOnaLimb

I have never personally used the "great stuff" foam on tree cavities, but my mentor back in Atlanta was big on it. I dont see how it would cause more decay in the tree, its just basically a man made compartmentalization right? I know that it used to be common practice to pour cement down tree cavaties. This however becomes a nightmare if you ever have to come back and remove the tree. I did a big water oak in Laffayette La. after huricane Lili hit two years ago. Sheesh, some knuckle head ten years prior had hauled up about 10 bags of quickrete and a garden hose and filled up the cavity. I think we ate up 3 chains getting that thing down.

Kenn


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## okietreedude1

ive seen it around here. it looks kind of funny unless its painted brown to match the bark. even then, it looks silly. i have a lg silver maple in my front yrd w/ hollow limbs that the birds like and ive thought of using there just to keep the dumb things out. havent done it yet, but its been a thought.


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## Guy Meilleur

*Foam-filled cavities*

Pros: Lessens twisting of stem which lessens cracking.
Lightweight
Cheap and Easy

Cons: Restricts air movement, but...when bark grows over a cavity, that restricts air movement, but is that bad?

I've seen trees where customers had used it after lightning strikes etc. Resonance testing showed no rapid growth in decay.
I'd use it if I thought twisting and cracking was a big problem (that could not be mitigated by reasonable reduction but ordinarily I like cavities to be open.


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## Kneejerk Bombas

> _Originally posted by netree _
> *No. It's a sponge that holds moisture in an area that should be allowed to dry out. It's also a nice springboard for wood-eating insects to get started. *



It is not a sponge at all. In fact it's a good waterproofer. Like Guy said, it'll make an air tight seal which should slow many wood decay processes.

I've done this a few times in the past. After you inject, it bulges out. Then when it's dry, you take your hand saw and cut it flush. On a light barked tree like White Oak, it matches great, otherwise you could paint it.
Upon revisiting the sites where I did this, all of them were attacked by wildlife. I figure all my work paid off because now the critters have insulated homes.


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## jmchristopher

I believe the stuff is formaldehyde foam, and actually is pretty harmless. In a small cavity it should make next to no difference to the tree, and if it makes the client happy, why not? The color of the stuff is obnoxious, as the okie pointed out. Black paint looks fine after a while. I'd recommend she set a dam made out of cardboard to help keep the stuff tidy as it expands. ( which it does like crazy)


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## alott

It's a lot better than cement when you cut in to it later , nothing like sinking the dogs in and sparks start flying, there goes another chain!!


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## kevintree

For those wanting to dry it, it is now avaiable in black

Kevin


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## Dadatwins

Thanks for clearing that one up 

I figured this would be a confusing one. I am going to contact homeowner and see if I can look at tree. Might try it out if conditions are ok. To the folks who have used it any prep involved ? I am guessing remove standing water if any, loose debris, ect. ?


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## OutOnaLimb

> _Originally posted by netree _
> *No. It's a sponge that holds moisture in an area that should be allowed to dry out. It's also a nice springboard for wood-eating insects to get started. *



The Great Stuff foam is a polystyrene foam that does not draw in water like a sponge. It basically expands to the consistency of the foam found in most cheap ice coolers. And since it expands at an overwhelming rate, the maximum area of the cavity will be filled and sealed off to moisture. Which is better? Maybe sealing a little moisture that the tree will naturaly absorb, or allowing large ammounts of water to collect and sit over the years causing more decay? As for the color yeah it is about the same color as Zing It throw ball line, but I think some one said it now comes in black.

:Monkey:


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## xander9727

I would only recommend or use it to keep critters and/or insects from taking up residence. Definately use the black.


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## MasterBlaster

> _Originally posted by Dadatwins _
> * She is worried about bees or something making a nest in the hole. *




So?


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## Trees Company

This is a joke right? Never use foam in a tree. The moisture from the tree its self will rot it out. Is this for real or what. You can never use it! I cant count the amount of times that I've seen trees killed from that stuff. Where they could have recovered but didn't because the foam makes a pefect hide out for insects.


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