Foam Filled Cavity follow up

This video follows a previous clip (about foam) and explains what we did. My thoughts on foam in cavities and the way a tree reacts to the foam are what I discuss in this video.

[@jimj4280]

My dad was the head of the TAMU Plant Sciences Department. He was also the personal arborist for LBJ. He dealt with exactly these kinds of problems. He taught me that you have to work to earn the recovery of injured and hollowed trees. He taught me that you can't cover up holes. You have to clean them out without injuring the cavity walls. Then you must regularly clean out whatever dead matter collects inside. It is a long term commitment that lasts until the hole has completely sealed over. You can help things along by providing good drainage at the base of the tree and minimizing the insects trying to live in and around the tree, but don't allow insecticide to build up in the soil around the tree. A hole pointing to the sky that can't be pruned can be loosely covered with a chimney cover type rain shield, but you will need to make sure there is plenty of space for moisture to escape. Screen can be used to keep out varmints and insects. Dad and I saved many an oak tree using his methods.

[@arboristBlairGlenn]

Good history Jim. Are you still an Arborist? Hope you enjoy my efforts to help others learn more about trees.

[@nchardcrab]

Awesome comment and advice!! After 50 years as an arborist I feel your father's method is absolutely the most practical way to approach large cavities. Specifically, a large cavity at the base of a tree can be tricky to deal with on a short term basis. Taking your time and being committed to sound horticultural practice is the only way to help trees with cavities survive. On the subject of large wounds at the base of a tree, I am a proponent of carefully cleaning out the canity. If the cavity is deep, plunge cutting a port a few inches from the ground for drainage is a great idea. Preforming these procedures requires long term commitment to the tree. To add to your excellent advice, if I may, I learned at technique called bark tracing very early I'm my career. I have seen the long term results of bark tracing. Used properly, I will stimulate cambium growth and help shorten the time it takes for that bark to curl into the hole..

[@highheatrichie]

I have the start of some cavity only a few inches on my American elm it’s like 50 years old and don’t wanna lose it! It’s full of water will defiantly have to get an arborist to look at it!

[@Saint696Anger]

I run into your videos whenever I have real tree problems so I subbed, you give good advice thanks.

[@arboristBlairGlenn]

∵§ain†♣∀₦₲ξℜ∴ thanks for commenting and helping me grow the channel.

[@bluewillow4985]

Thanks for this video. I think you Are spot on in your recommendation. I have a huge beautiful Elm right in front of house that is suffering from several issues. No aborest in my neck of the woods. I am learning alot about trees.

[@jamesb3092]

I must agree with you Glenn. Just using common sense, I’m no arborist. I do have three huge live oaks that have grown down to the ground with 40’+ lateral limbs I need to prune. Hence my video choices and how I have come to watch your videos. You do a great job, very informative! Wish you was close to central TX, I would certainly give you a call. For financial reasons I will be pruning the trees myself. And I have seen some real hack jobs that people have paid good money for as well. Thank you for sharing your knowledge. No idea how close you are to 1k videos but I hope you don’t stop there!

[@Treegurubob]

Great video.... Nice to see this kind of thinking on the tube....

[@arboristBlairGlenn]

Bob Brennan Thanks Bob

[@lubbockarborlogical440]

Good call Blair. The environment for wood decay has basic requirements. Moisture, a food source (wood) and an acting pathogen. I have spent my career spreading the message to my clients that a magical spray, filler, coating or elixir does not exist to prevent the spread of decay in trees. Your video does a great job to illustrate that as an arborist the best thing we can do in regards to decay is to eliminate the environment that is conducive to decay. In other words take a get wet stay wet environment, such as a hollow trunk that has been backfilled with foam and remove the foam to create a get wet dry out environment. This is one variable as to why some desert tree species can live for thousands of years. Great video. Kudos to Shigo.

[@arboristBlairGlenn]

Lubbock Arborlogical I’m fortunate to have met and attended my of his conferences before he died. Dr Alex Shigo was a major influence in my life. His energy was contagious!

[@Floppycats]

thank you for your video - my gut told me not to put spray foam in the cavity in my silver maple as the arborist suggested. just didn't seem right and now i have the knowledge to explain why.

[@MrMerrBear]

So don't fill cavities with foam or concrete. That is clearly understood, but what can be done to prolong life of a tree and keep it safe short of cutting it down?

[@richardb7093]

Sound like the foam was not properly applied.

[@blardymunggas6884]

Silicone perhaps?

[@derekmaynard5619]

Doest seem like that's an answer we will get. It's unfortunate because saving the tree is best.

[@stankochanoff9603]

Good information Blair, I have a client in Halifax that was wondering what to do. I'll pass your video along. Stan Kochanoff, Registered Consulting Arborist, Falmouth, Nova Scotia

[@arboristBlairGlenn]

Many thanks. Cheers from California

[@rln970]

This video answered a question I had about a tree at my former house. It was a silver Maple with a 6' diameter trunk and three trunks. There was a cavity similar to the one you showed. For 22 years, I just kept it cleaned out, but never put any "sealer" in the hole. Since starting to follow you, I had been wondering if I was right. Looks like it was the right decision.

[@arboristBlairGlenn]

Dick Nix cavities are not good but filling them just hides the problem

[@rangerstl07]

I don't work on trees but in my experience with cars and boats... if you try to make it difficult for water to get in, all you do is trap what water makes it inside. You can never keep water out.

[@pcno2832]

The trick is usually to seal the top, but allow just enough drainage at the bottom, but it's tricky. It's always tempting to seal for the sake of sealing, a great example being the bead of caulk that's applied between tubs and tiles, which always turns soggy and moldy after 6 months. With tiles, its easy enough to say "don't do that", but with something as inherently messy and irregular as foam, stopping water from getting in while letting it out if it gets in anyway is a lot harder.

[@gillianmartin7578]

I am so pleased to hear your recommendation and the reason for it. Did you know that the EPA is recommending expandable foam to fill cavities to prevent the breeding of mosquitos? See article in August 2018 issue of Tree Industry Magazine on line. Balancing tree health, human health and wildlife interests is an ongoing challenge but as the Director of the Cavity Conservation Initiative, I was deeply concerned about the lack of consideration for cavity nesting birds and other wildlife that rely on cavities for nesting, protection etc. Collaboration between disciplines is vital before releasing recommendations that can have harmful unintended consequences. Departments in government often do not work together as they should. And this is a good example that ecological interests can be forgotten or ignored even by the EPA.

[@arboristBlairGlenn]

Gillian Martin makes sense but not in the best interest of the tree. Mosquitos are indeed a problem.

[@artiewoo7073]

I have an older tree that has holes in it from woodpeckers and such. What is the best way to seal or cover these holes so bees do not build a hive inside the tree? I was thinking of using some screen or mosquito netting and stapling it to the tree. Any suggestions are much appreciated thanks!

[@thomasholmes7070]

Smart advise. Thanks.

[@arboristBlairGlenn]

Thomas Holmes 👍🏻

[@andyinthevalley9900]

Second question, Is there any kind of systemic fungicide/other you can water the tree with to slow the rot down?

[@wilmalloyd]

Cool...but what do you do next with the cavity?

[@kurt.leucht]

Same here. I know better than to fill the hole with cement or foam. But what are the next steps to discourage rotting and to encourage natural growth around it? I have an upward facing cavity in the crotch of a live oak tree. Do I just continually keep it cleaned out of leaves and rotting wood and cross my fingers?

[@jrasche]

I just had a large maple tree that was very rotten Cut down to about 3 feet tall. My husband and I were thinking of just decorating this as your typical gnome house. We noticed on the backside that it is very riding almost going into the center. I started having this idea filling it with foam and then I found your video here. I do want to decorate it as the gnome house but I’m curious if I just dig out the old rot and leave it if it would stop rotting, or slow. Someone suggested I should plant the top of the top of it but I’m thinking doing that would just help it rot faster. Bottom line i can’t afford to have it ground out so I want to decorate it to just to make it look somewhat nice but at the same time don’t want to spend a lot of time doing it if it’s just gonna rot in a year and collapse. Do you have any thoughts on this?

[@inthegulley]

Very insightful. Thanks

[@arboristBlairGlenn]

Where is the “gulley”?

[@bdog792]

I agree with your assessment from firsthand experience. I had same situation with a tree and was told to fill it with foam and cap the foam with tar. It didn't work!

[@arboristBlairGlenn]

B Dog we learn from experiments but a lot of people don't read the results

[@suewhite6827]

Thanks for the video. You have just saved me from making a bad mistake. All everyone says is to foam the one I am dealing with but it just didn't make sense . From my perspective there is not a thing on the market that can stop all water from going down into the hole. From experience I know ants love a rotting tree

[@arboristBlairGlenn]

Important to understand that while there isn’t anything we can do to fix it, we can make it worse.

[@Patty-qd1lz]

So, what did you do with the tree!!

[@AmirHandle]

Thanks for the video. Do you suggest to apply the special wax on the spots right after pruning branches?

[@arboristBlairGlenn]

No, tree sealant is no longer accepted as a procedure. Best to let the wounds dry out

[@MrStupidcessnuts]

Whats your stance on painting a large cut?

[@giorgiobosoni6172]

No Blair, you're absolutely right, I also had to deal with foam sprayed in a large cavity at the base of a 400 years old sweet chest nut. Over here in Europe, this method to treat cavitys, is no longer used in modern arboricultural contest because of the further issues due to such practice.

[@igorsinger3455]

the use of such a foam is interesting from the convenience. But one of the most educated chemist and I know nedostatkm foam. The first is the instability to ultarfioletu The second one is not living tissue friendly substance. But the question of the spread of fungi under any coatings (whether it is cement, construction foam or bitumen) excites me more. I am very late to read and Shoigu at me because his theory has not made such a stunning impression as I was guided by theories (I called them lamiarnymi radial diffusion pathways in living plant tissues). And gribami- let me remind you that the fight against infection of wounds, doctors very long resisted. The main problem is that none of the known fungicide and septic tanks is not stored in the wound is very long (2-3 months prior to the period of decay can a little over). Question is relevant and open.

[@guntherultraboltnovacrunch5248]

Probably his second (or third) language.

[@drew856856]

i completely agree with you

[@3beltwesty]

An old stunted Live Oak is here had this giant Gash back in 1971 . No bark from ground level to 6 ft high. One THIRD of the bark gone on the tree. A limb probably ripped off during Camille and or the Subdivision Bulldozer guys did it. :) Anyway all the middle age tree expert said to cut it down; it never will survive. Any old 85 year guy said it will outlive all of us. Just trim back the living layer with a V trim and keep insects out of it. Anyway it took about 30 years to fully close all that gap up. I never used concrete but did use treated wood scraps, rain shields I moved around. . Chiseled out voids. DID use spray foam is small amounts. The first foam I bought was like late 1970's. Used left over roofing tar too. ***BUT I never did any giant fill the cavity gambit. *** Usually just did where the living layer would cover over in a few years. The real issue with a giant fill of stuff is you cannot know what you are hiding and what is living there. lol :) That tree got to be rather interesting since once the top was closing well the ground area got rot. The last to heal up was the bottom part. To measure the grow back rate use to use the old 1960s 4H club stuff. Draw an reference control 1 inch from the active area. Sharpies fade. Pencil does not. Some folks use to use tiny tiny nails.Anyway a year later the grow back amount is highly variable. Might be 3/4 inch one place and others 1/4 inch and others zero.

[@arboristBlairGlenn]

Trees are survivors!

[@tubeloverforsure]

What you are saying seems to make sense. Let me ask you a question. I have a small tree in my yard that has a gap or opening on its side of the main trunk about 3 feet off the ground. I cleaned out all the rotting material and dirt from inside the hole. I found some termites inside and destroyed their tubes and killed the majority of them by using a flat piece of metal to dig them out. Then after I cleaned out the hole the best I could I sprayed black pruning seal inside the tree to coat the good wood to help protect it. I checked today and the pruning seal coating is dry and hard but my hole in the tree is still there. Should I just allow the hole to remain open so it will continue to be dry inside the tree? I am kind of worried some bees or ants might try to build a nest inside the exposed hole. Do you have any suggestions? I am thinking the smart thing is to NOT put anything in the hole and just allow the opening on the tree to close by itself over time if it ever does. What are your thoughts? Thanks...

[@arboristBlairGlenn]

tubeloverforsure while the hole is a problem, covering it up does not help. In theory, sealing up a wound should protect it but the decay will continue under the covering. Sorry, no good answer here.

[@heinkristen1]

I have a very large maple tree two huge main trunks on one large base, it has a cavity that looks very simular to the one on this tree near the base. It is very close to our house. should it be cut down? It has never been filled with anything, the tree seems otherwise healthy and provides a ton of shade for our house, but I worry if it will fall. We have called a few people to look at it but I don't know their advice is trust worthy, they are willing to do anything you want them to even if it is not good for the tree like topping it was a suggestion of one company. I wonder if they will suggest anything to get me to hire them for a job. please any advice?

[@chrisreimers84]

This was very helpful. Thank you. I have a cavity in pretty good sized tree and it is catching and holding a lot of water. Would it make sense to siphon it out occasionally? I've only recently started looking in it because some sort of white growth (about the size of a fist) started growing just above it. We've had a very wet summer thus far here in Arkansas. I've watched more youtube videos than I want to trying to figure out what the white matter is and can't so I'm figuring it is some sort of fungus. Thought I would ask you what you would do before removing the white blob, siphoning, or spraying the white thing with some sort of homemade fungicide made of natural stuff.

[@arboristBlairGlenn]

The white growth sounds like a lions mane fungus. As for the water, it’s not a good thing but don’t drill a drain hole. If you want to try and syphon it out, fine but the problem is still going to decay. The fugal organism is deep in the tissue of the wood. Sorry

[@chrisreimers84]

@@arboristBlairGlenn Wow. Thanks for the quick answer. So, I'll tear off the fungus and leave the water in the hole.

[@arboristBlairGlenn]

Chris Reimers kzbin.info/www/bejne/Z6auloF5fNeGotk

[@chrisreimers84]

@@arboristBlairGlenn My wife looked up Lion's Mane we found out it is edible. I'm going to take a closer look. Supposed to be good for the brain; I could use some of that. Thank you for the video! This one is pretty small so I don't think I'll be eating it but this is good to know. :) Btw, the tree is right next to a seawall and seems very much alive (lots of leaves). I'll keep an eye on it and when I think there is a chance of it falling, I will cut it down.

[@RichardRoy2]

I've heard of various approaches, these among them, which I tend to agree with you on. Decay depends on bacteria, I'm thinking. So, what if you use a disinfectant for an attempt to halt decay, followed by an oil or wax to keep the opening from drying completely out. Which, I'd think would also be a desire. Not completely clear on that. Or would it be better to allow it to dry out,after the disinfectant, then apply a wax coating. At least till the wound grows over? I know something as severe as this is not very apt to grow over, but if you're making large cut backs, it takes longer to grow over, so...?

[@arboristBlairGlenn]

Nature returns to the soil. Can we slow it down? Maybe. But in the end, it all goes back into the earth. So many things have been tried without success.

[@buddybuddy905]

Thank you

[@rcmen231]

Can you carve out some wood from the crotch cavity so that water would have a way to drain out? Like instead of having a pocket where water can pool, maybe cut an opening so that water can run out some way. This may harm the tree in terms of cutting a piece out but at least there would not be a pool of water where fungus can grow and do more damage. What do you think about this idea?

[@arboristBlairGlenn]

+rcmen231 It is better to have the water sitting and drying out than cutting into new tissue. Dr. Alex Shigo explains this quite well in his books.

[@rcmen231]

Cool thanks.

[@richardfederico1672]

This is a tough one to call and there are not too many good options here. I guess the best option is to leave it open like you said, but most people aren't trying to save the tree when they cement or foam holes so much as they are trying to keep unwanted pests from making a home in it. Parents don't like their kids running in the house screaming that a raccoon came out of the hole in the tree. It seems to me that a big hole means the trees days are probably numbered, eventually the heartwood is going to be eaten out and rotted further up the tree causing the branches to become compromised. This is dangerous depending on the situation and location to people or passer-byes. So there are many things to consider including species of tree, expected life of the species and whether or not to just cut it down and plant new. If the tree has an invasive bug or borer, then you can try pesticides and be committed to managing the hole, but I don't know too many people so committed. So hypothetically with all factors considered, maybe a combination pesticide treatment, then foam fill with a shell like material or tree tar applied over foam to cap and waterproof. Not perfect, but maybe the best compromise.

[@arboristBlairGlenn]

My comments on what to do are not my ideas or thoughts. These are well researched studies on why you don't fill cavities. Arboriculture is a science based on research and evidence.

[@TheCablebill]

@@arboristBlairGlenn executive decisions are based on circumstances wherein the scope of the science being cited could be inapplicable. The science can only forecast what would likely happen to the tree over time given various treatments. It cannot determine which of those outcomes are relatively more desirable for the tree owner. Perhaps we should ask the tree what it wants. Maybe it's grumpy about kids swinging on its limbs and it will demand a fence.

[@arboristBlairGlenn]

buymeacoffee.com/blairglenn

[@jamessanders6910]

So - the question comes down to what DO we do???? This offers no solution!

[@arboristBlairGlenn]

James Sanders it’s not about what we can do. It’s about recognizing that we can make it worse. Best to just leave it to dry out or stay open. Study Shigo.

[@Creator_Veeto_PAEACP]

arboristBlairGlenn that was the most profound lesson you have taught me.

[@phillipfranklin9353]

@@arboristBlairGlenn problem is that the hole in the crotch that you opened up by removing the foam will collect water and be open to pests. Hence , with a crotch area that has become water holding / retraining has to be remitted / treated . any suggestions ? FYI, I have seen other videos that still recommend foam . kzbin.info/www/bejne/m5e2Z2iMht53kNk

[@arboristBlairGlenn]

Phillip Franklin I’m quoting Dr Alex Shigo on this information. As the tree develops further, all cavity fillers crack and allow water in. At least an open cavity will evaporate. The big issue is about hiding a problem. Decay will continue regardless. A hidden cavity becomes “out of sight, out of mind”. I have opened many foam filled cavities full of insects and full of decay.

[@phillipfranklin9353]

@@arboristBlairGlenn I know. Cavity fillers are a bad idea. the only solute I have come yup with is a roof over the crotch thereby stopping water from getting into the spot. I am thinking of using foam board . TY for your response and help.

[@cynthialaw933]

@arboristblairglenn, My question is, If insects entering an old cavity where moisture and decayed wood is present are a concern, would it be wise to apply an insecticide? And if yes, which one would you recommend?

[@arboristBlairGlenn]

Cynthia Law I can't legally recommend insecticides. Not really a fan unless absolutely necessary

[@scooter2d2]

@@arboristBlairGlenn can you suggest food grade diatomaceous earth to control the ants?

[@timkirkpatrick9155]

I have experimented with using foams many decades ago and concur about not using them. They do no good and can accelerate damage. The sole exception was one tree which had a very ugly void and was positioned such that removing it immediately would not have been possible. A public event was scheduled in the very near future where the tree would have been missed and was very visible. We did a foam cosmetic make-up job, complete with paint to make it look healthy. Removed some weight above the void to reduce risks and came back 45 days later and removed the tree. The cosmetics were good enough that people thought it was fixed and objected to the removal. Some days you can't win for losing!

[@arboristBlairGlenn]

Tim Kirkpatrick great example Tim. Where are you from?

[@timkirkpatrick9155]

Blair, I come from central New Mexico (Albuquerque area) I live at 6700ft.

[@timkirkpatrick9155]

I am in central New Mexico, Albuquerque area. I live at 6700 ft elev..

[@daviddemitruk3819]

If foam is still used, would it help to seal (exterior construction sealant) with sealant in the areas where the foam edge is next to the tree bark as an attempt to keep the hole dry? You would probably have to re-seal occasionally.

[@arboristBlairGlenn]

"Sealing" a wound or open cavity doesn't work. Even a tight seal in a growing tree is ever changing. Best to leave them open to inspect. Study Shigo's work

[@rickreno2492]

The lumber yard sells 30 year silicone caulking !!!

[@daviddemitruk3819]

If the tree i living in an area that gets a lot rain, won't the hole rot out, and maybe rot out the inner portion of the tree? What about termites getting into an opening like what we have discussed?

[@n0sr3t3p]

would putting a "wick" in the hole, to induce a capillary action, help keep the hole dry?

[@arboristBlairGlenn]

Interesting idea but the seasonal rainfall will still add water so my guess is, I don’t believe it would do much. There was a conference I went to years ago and the speaker stated in a cavity that stays wet, is better than wet/dry/wet/dry because under water it becomes an anaerobic condition. Then the question of mosquito breading spot came up.

[@optyman]

What about filling with tar compound? They sell these in cans or could use some sort of roof tar to keep insects and moisture out.

[@arboristBlairGlenn]

No

[@genegoodman5233]

I’ve got a tree that is similar and want to know how to keep water and trash out. If is stands full of water and freezes that will split my tree. How do you help save the tree?

[@arboristBlairGlenn]

Gene Goodman a cavity does not heal. It grows around the decay. It should dry out in the summer if there is no rain. A bit of plastic covering may help if you can adhere it in a way that allows you to open it up on the summer to dry out. No good answer here, sorry.

[@wilmorris4225]

Well I need to close a large hole that gets honey bees regularly and it is in an apartment complex so I need to make sure this doesn't happen anymore. My thought is to screen and stucco over the hole. I see that you make no recommendations but the hole HAS to be plugged. Due to the positions and angle of the hole, I don't think water is going to be an issue. What are your thoughts?

[@arboristBlairGlenn]

Wil Morris just staple on a screen but leave it open to dry out

[@joncozzi1701]

I agree 100% ! Those arborists were dead wrong. If you know who they are you should send them this. Great work as always!

[@arboristBlairGlenn]

Thanks for commenting Jon

[@billquillin1952]

I completely agree with you! Left alone, trees have an amazing ability to heal themselves of injuries. Hiding a problem doesn't help. Preaching to the choir, aren't I?

[@arboristBlairGlenn]

Bill Quillin remember that trees don’t “heal”. They absorb the wound and grow around it. The term compartmentalization is used. The hope is that new stronger tissue will be able to grow faster than decay spreads.

[@billquillin1952]

arboristBlairGlenn I was kidding a bit. By the way, I love your videos. I learn from each one.

[@lovera3878]

I would like to leave my wound alone but carpenter ants took up residence. As I mentioned above, perhaps after I keel the ants and control their access to the tree with tanglefoot the tree will be able to heal properly.

[@Thetimecapsuletx]

What would happen it the foam was sprayed over with a sealer to keep the water out?

[@arboristBlairGlenn]

It’s not a repair and sealing the water out does nothing positive. Sealing up n the moisture leads to mold and fungus. Hiding the problem inhibits future inspections.

[@rezaasadi5773]

I think u are absolutely right

[@arboristBlairGlenn]

Thanks but it’s not my conclusion. Dr Alex Shigo talked about this many years ago.

[@rezaasadi5773]

@@arboristBlairGlenn Thanks anyway

[@tonysmith7283]

Rigid foam doesn't move as the tree grows and flexes, also it is not uv stable, consequently concrete would provide a plug which can be maintained as the tree grows over the plug. It would require periodic inspection. Another technique which provides air circulation is metal flashing nailed over a blind pocket.

[@arboristBlairGlenn]

Read Dr. Alex Shigo's work on cavities and why you don't fill them. Very enlightening

[@NoctilucentArts]

I found your video researching my problem. It's a cavity at the base of an old apple tree, which will obviously be filling with sitting water (I'm in Portland, OR). I was actually thinking of building a little roof over it to shed water and stapling a screen over it to keep debris out. What are your thoughts about a coating of spray tar inside - to coat the surface, but not trap water like foam does....?

[@arboristBlairGlenn]

Study Dr Alex Shigo’s work on the subject. Best not to coat it. Sound right but studies have shown that doing so is of no value

[@dustinflores2367]

I currently have a customer with a huge hole like that right at the main Y of the tree, I’m debating on weather to fill it with a mesh screen and flex seal, but I’m not sure if that would be better or worse for the tree. I know airflow can help prevent a lot of disease so I’m unsure

[@arboristBlairGlenn]

Dustin Flores generally best to just leave it alone

[@dustinflores2367]

Thanks Glenn ! That was my gut feeling but I don’t have the knowledge you have so that’s why I asked! Thanks so much for your knowledge and teaching. Great videos to learn from

[@General_reader]

if you don't like foam, then what method do you recommend?

[@Deke1]

chainsaw, cut tree down!!

[@jasonsejkora4578]

Depending on the severity grafting a lattice work over the wound can work. I've seen it done in orchards to save 100-year-old heirloom apple trees. Looks pretty neat after a few years when it looks like a zipper. Takes time and consistency but if it's a 150-year-old tree on your property you probably are in for the long haul anyway.

[@jerrybear3081]

was going to do this to my hickory tree. not sure what other options there are the tree fills with water and the water oozes out the side of the tree two feet bellow the crotch. im afraid i might need to cut it down. i will keep watching your videos to find a solution, thanks.

[@arboristBlairGlenn]

Jerry Bear no good solution to decay but it is important not to hide the problem.

[@TheCablebill]

How is that tree today?

[@stevetenhundfeld952]

I would have cut a notch in the pocket to allow the water to escape. when i cut a limb.I cut i flush with trunk usually takes three cuts and a little chipping . the bake will then grow back and cover the cut with time. What are your thought as to my methods?

[@derrickbooth8070]

+Steve Tenhundfeld Drilling a hole and inserting a pipe would be better. You never want to make your cut flush with trunk. Just outside the Branch Bark Ridge is where you want to make your finale cut if done properly a healthy tree should have no problem closing the wound.

[@arboristBlairGlenn]

+Derrick Booth read up on the research about why drilling is not correct

[@arboristBlairGlenn]

Leave it alone. Read Dr Alex Shigo's research

[@jrapanut0]

I do too agree I've did too years ago ( 10-15 ) thought that was was a great Idea, because I hated working on tree's with concrete ! over the years I have learned through experience. What a bad Idea Like you mentioed it will not dry and here a great Video to prove it..

[@lanceburke6236]

Crazy to me what people will do. I agree totally, remove useless plug. On a smaller pocket on base of tree I was thinking of removing any rot, wash and thoroughly dry. Not sure what to cover it with. Like too seal it without plugging it!!?

[@arboristBlairGlenn]

Lance Burke best to just leave it open

[@karintetzlaff.averbeck.5895]

Have you ever built a small roof over a cavity, that would keep water out but allow air flow?

[@arboristBlairGlenn]

Seen it tried but to no positive benefit

[@rjcbr1191]

​@@arboristBlairGlenn Sounds like a great idea not only practical bur with a little creativity attractive. So ​ arboristBlairGlenn, if at first you don't succeed etc.

[@rjcbr1191]

Your idea is great! I want to build a fairy garden environment in my modest sanctuary and protecting these cavities fir the tree as well as small animals is a creative solution. I think.

[@kurt.leucht]

I don't get it. A roof would keep rain from falling directly in from the sky, but how would a roof keep water from running down the tree bark and straight into the hole? Are you thinking about sealing the roof all around the hole or something? I don't get it.

[@acmilancrazy]

I know this is really old at this point, but I'm doing research on whether or not a specially formulated foam could be helpful to do what the original arborist was hoping for. My question is, do you think that the end results could be better/different if the tree cavity was first sprayed with a hydrophobic coating, and then filled with a *closed cell* foam (rather than open cell, which absorbs water - you could also paint the foam to match the tree to seal the foam further) that perhaps also contained some sort of natural insect killer? I was thinking that adding a hydrophobic agent that drives out water could also be good to mix in to the foam recipe. Been thinking about trying to formulate some sort of foam like this that's specially designed for trees with this sort of issue...just wondering if you think it's possible that with the right ingredients, a foam could actually be helpful to a tree (even if only used temporarily, as part of trying to heal the rot). Also not sure if a hydrophobic spray used on recovering wood inside a tree would hurt the tree or prevent it from healing...would love to hear thoughts!

[@arboristBlairGlenn]

Well, if you read Dr Alex Shigo’s work on the subject, he concluded through extensive testing and dissecting of trees that there isn’t any cavity filler that resists decay or insects. Now you can try but unless you take the decades of testing to come to an accurate conclusion, then my understanding of the subject is that it won’t work. Seems to make sense but decay always wins. We used to seal wounds with tar, that also has been proven to be of no value and in some cases, makes things worse.

[@arboristBlairGlenn]

Follow up, that tree fell apart

[@guerraarmy]

I used a cardboard box to fill the hole then I spray foam. After the foam dry, I sprayed flex to seal the foam and keep water out. Update 4 years ago and my oak tree started to heal it self and somehow the foam is getting push out. It may be case by case. keep in mind the arborist for some reason used to recommend concrete. what is your thought? I'm in Texas.

[@arboristBlairGlenn]

I’m a student of Dr Alex Shigo who spent his life studying this. Final determination, filling does nothing positive. Best to just leave it be.

[@TheCablebill]

How is your tree today?

[@guerraarmy]

I remove the foam on 1 oak tree it seems it is healing didn't see bugs and water. Inside tree was dry

[@koholohan3478]

I know you typically discourage trying to fill cavities. I saw a case where it worked perfect...probably rare that it works. The tree near my work had a couple large trunks removed from the main trunk down low. They filled it with cement and the only reason I know that is because there is a tiny peep of grey cement is the middle of a big circular scars, about to close up, and there is cement a little on the ground where it dripped while they were patching it.

[@arboristBlairGlenn]

Kalista Hall the point here is the cement did not "fix" anything. It just hides the future decay making it impossible to assess

[@koholohan3478]

Yes, I understand. It would had probably healed over the same without the cement. It usually probably doesn't go that well

[@arboristBlairGlenn]

Kalista Hall Tree's don't "heal". The grow around a wound in a process called compartmentalization. The decay continues under what appears to be a closed wound.

[@koholohan3478]

arboristBlairGlenn and I'm sure that being complete encapsulated within a tree once it is dead causes a lot of havoc for you guys when you eventually have to remove the being.

[@arboristBlairGlenn]

Kalista Hall sometimes it does

[@robertgreen2288]

Just returned from New Hampshire we were on a trail hike when we had noticed a landslide had occurred. The trees were at all different angles

[@arboristBlairGlenn]

robert green you never know what you are going to find, unless you take the time to look.

[@rubybackert3612]

I find it interesting, one arborist says to fill with urethane not polyurethan, another says not to. One says don't cut into the good tissue around the decay another says to cut a v-shape to let water drain. Who's right? I have a tree on the property I just bought that has had this ivy on it. (I'm working on getting rid of that) but there is a hole that is deep and holds water. I did get almost all of the water out of the hole and because it was going to rain I covered the hole over and secured it so no more water would get in. Next day I removed that so the hole could begin to dry out. Made some sense to fill hole but seeing this video I don't think so. What to do?

[@arboristBlairGlenn]

Dr. Alex Shigo was the Arborist who studied these questions and has written many books on this and other confusing issues with trees. I had the honor of seeing him speak many times and I have read his books. His work has changed many aspects of this field and cleared up a lot of ideas about how trees react to these treatments. His jobs b with the US department of forestry lead him to dissect thousands of trees.

[@peterservon9370]

Foam CAN keep water out if applied correctly. Urethane foam has 10% elasticity. Foam will degrade over time when exposed to the environment, and should be readdressed when necessary.

[@arboristBlairGlenn]

Sorry, not a solution

[@varunsharma4817]

I think you should use this urethane foam mixed with some sort of medicine or some bug repellent and moisture desiccator.

[@arboristBlairGlenn]

Varun Sharma listen to the video

[@unalgenis2326]

Hi Blair, my name is UnaI from Turkey. Have an idea crystal clear Plexiglass and silicone sealant we can cover cavity and rain can't go in also we can see in cavity. First we can clean and disinfect rot then we can apply tree vaccine paste.

[@ctuan13]

So having watched most of your videos concerning treating cavities on trees. It's clear that filling the cavity with any material in an attempt to seal it off is a terrible idea. However, in crotch areas of the tree with an open cavity, what if a plate was fastened using loose rope that was several inches above the actual cavity entrance, simply serving as a sort of "roof" to prevent rain from entering and filling the hole? Would that help at all?

[@arboristBlairGlenn]

ctuan13 you can try to keep the water out but decay will still win.

[@DrewanNicholson]

Thank you for this video. I was considering doing this, now will not

[@arboristBlairGlenn]

Drewan Nicholson 👍🏻 kzbin.info/www/bejne/aHzJhYR6drxmq6M

[@jimbob5013]

The most effective way to eliminate water from entering tree cavities, would be to erect very large umbrella type covering it is very time consuming, but most effective.

[@arboristBlairGlenn]

Jim Bob uhh, ok then

[@DragonsBreathCreations]

So, I have a large, narrow cavity in the 'crotch' of a 70 year old grand oak tree that was created by a termite colony. The trunk is about 6' in diameter and the cavity is possibly 12" in diameter. The termites have been eradicated, but cavity goes down at least 4 feet and tree appears to be solid otherwise. Here's a strange thought... What about planting another small oak in the cavity and and having them grow together over the years, thus filling the cavity naturally? Thoughts??

[@arboristBlairGlenn]

Dragon's Breath Creations creative thinking but not a good outcome. Decay is still decay. Planting in the decay does not eliminate or slow it down.

[@arboristBlairGlenn]

Dragon's Breath Creations send me photos. [e-mail]

[@andrewmarker4157]

Ok, I have several cavity trees on my new property, with that video I won't be using foam. Thanks for insight 👍

[@arboristBlairGlenn]

Cavities are bad but we can make them worse

[@derrickbooth8070]

That's exactly what I did for a customer. Told him you can't keep the water out it just needs to be able to dry. However I nailed a piece of wire mesh over the hole to keep out debris and using a small dia. 1.5' long drill bit around the trunk under the cavity to determine how bad this cavity is and how safe the tree .

[@MrSandcrab1945]

So, I was on my way to buy foam for my tupilo tree. Noe (I have second thoughts.

[@josephsawatsky]

So what do you do with a hole Just leave it I dont want wasps in ours

[@arboristBlairGlenn]

The question is not about “what you do”, it’s about what is best for the tree. Filling just hides the problem. Being able to inspect the cavity gives you the feedback for educated decisions.

[@natassha4275]

i agree with what you have mentioned but what or how would you fix cavities like these .... im in south africa and have my own tree felling business not quite as large as yours over there but trying to work my way up to your levels and learning slowly if you are interested i have a facebook page KSV TREE FELLERS if you see any faults in my work please comment on the page thanks for the awesome videos thumbs up.

[@pcno2832]

If there is right right way to fill such a cavity with foam, this obviously wasn't it. But I'm picturing the use of an insecticide-fungicide foam, with some kind of flexible sealer sprayed into the cavity first, the foam next, cut to a smooth graded surface to allow water to run off, then an outer layer of sealer, finally, weep holes at the bottom, filled with a porous material hostile to insects that would still let any water drain out. Has anyone made foam filling work?

[@arboristBlairGlenn]

PC No the theory is good but if you read about Dr Shigo’s experiments, to date, best to leave alone. Future inspections are not possible if filled with anything.

[@tappakeggaday1]

I think I have watched a few of your videos today,The fiasco with the iron giant. I understand wanting to keep trees and I know when you come across trees like they are trussed up like christmas turkeys I know your first thoughts are " oh god what did I do to deserve this"...I know there were a lot of old schools of thought when it came to trying to save a tree but honestly when you have that kind of core rot going on in a tree wouldn't it just be wiser to cut it down and grind the stump out and plant a new tree for a new generation? Everything dies, rusts or eventually breaks down to its base components. And no i'm not advocating just going out and cutting down trees for no reason but when it comes to a judgement call on something like this wouldn't it be better to take the tree down instead of a high wind come up one night and lay one of those ton branches in a bedroom?

[@arboristBlairGlenn]

This tree is not a hazard to any structure

[@peterservon9370]

Yes. You do not want water getting in behind the foam. That would be true for ANY material you use to block the cavity from infiltration. What do you suggest? Don’t expose a problem without proposing a solution.

[@arboristBlairGlenn]

That’s the whole point of this video. There is NO solution. But you can makes things worse. Study Shigo’s work and you will see

[@DanaKaempen]

This was great info - thank you for posting it. I was considering filling in a minor, shallow hole that was left in my tree as a result of pruning off a decent-sized limb. But after seeing this video, I'm not so sure it's a good idea. Clearly, foam is not the way to go for all the reasons you showed & explained. I just wonder if I should be applying anything to minimize water and "stuff" accumulating in the hole. Would that brush-on tar work?

[@arboristBlairGlenn]

According to the research, no. Best to just leave it be. Putting tar on a wound can trap moisture and speed up decay. Decay will occur but you can make it worse.

[@Daniel08353]

So many certified arborist say it’s good and helpful to use expanding foam, what I’ve always question this, since I know, water will see through it.

[@arboristBlairGlenn]

The expanding foam keeps bees from building a hive, and keeps animals out. It does not help reduce decay, fungus, water or insects. I don’t like it because it prevents inspection. Not any positives from my experience. I have seen so many foamed cavities full of problems. I have seen it used to reduce mosquito breading in water deposits so for that, maybe.

[@weekendhomeprojects]

I couldn’t stop itching...ha

[@marttoor]

Well i think you are absolutely right, it seem to do more harm than good!

[@AG-yj1jv]

Has anybody tried a LIVING PATCH? While it is a good idea to create something (with materials that won't break a chainsaw years from now) for the living bark to form around instead of curling inwards, trying to stopper up a tree altogether may not be a good thing. In Northern Ireland 30 years ago, I remember a news story about hollow trees. Researchers had studied all the massive trees on a bunch of estates over a period of years/decades. They found that the trees that were able to withstand the worst wind storms storms without breaking, were the ones that were hollow, and so could bend and sway -- trees that, previously, might have been slated for removal. So...Dead, rotting wood inside a tree is NOT a problem. HOWEVER...Critters that kill more of the living tissue ARE. Another vital point is that trying to stop rot of exposed heartwood only leads to water and bugs getting in behind it. The Encyclopedia of Trees and Shrubs warns against either drilling drsinage holes or using ferrous wires or fasteners. Soooo....why not create a living patch, grafted from a layer of livng wood removed from the trimmed off branches of the same tree? Then one could wrap the area with tied-on mesh to prevent critters from gnawing it? Thoughts?

[@arboristBlairGlenn]

I have seen efforts to add grafted small limbs to bridge bad areas. Not seen long term results

[@aliciasmith3440]

Glad I found this, seen a guy use foam. Know not to now.

[@arboristBlairGlenn]

Just hides the problem

[@jimearl6795]

We are looking for a remedy. Do you offer any solutions? No!

[@arboristBlairGlenn]

You clearly didn’t understand. We can’t always “fix” a tree. BUT, we can certainly make things worse! Be safe my friend.

[@henryholliday1]

and this is why I have no more trees lol if it looks rotten it is gone and here in NY there are dead black pine trees as far as the eye can see from the southern pine Beatles and we also have dwarf pines that only grow here on long island NY

[@Mutlap]

others say the foam enables the tree to grow over the damaged area.

[@arboristBlairGlenn]

Mutlap still others say the foam hides the decay and prevents you inspections. Foam does not keep out moisture nor prevent insects and decay. That is the same theory that has been used for the last hundred and fifty years using cement.

[@erlinglea4122]

thanks for info so best just to leave it and no foam

[@arboristBlairGlenn]

No foam

[@erlinglea4122]

@@arboristBlairGlenn thanks

[@billclark4301]

Had tried this technique on a hard maple planted. As a dedication to a first born child in 1955.N.W. IL carpenter ants and dead wood I shop vac to sound wood. Approx. 20" dbh. Dried interior walls using hair dryer. O-nite. Only 3" thick cylinder wall. Ant kill spray for residual. Foam. Approx. 3' vert. Callous x 3.5" w.. No sign of ants following spring/ summer. Tree was not pruned correctly when young and only 24' from house, so cabled in triangle since narrow crotch toward house. Then summer storm split 32' vert.tear,but cable saved new vert.striated cedar siding,triple lam.shingles,plyw.soffit/cedar fascia, and tempered triple pane windows. Still leafing out like a Pollard 16' look. Wanted to see how long the uv and ants to destroy the "barrier." Now the 2nd year I see insect holes in very powdery foam surface. If a photo is desired before I cut into the "patch" job,I will forward photos. [e-mail] Thabk you again for all your insights. At 68 I still enjoy climbing thru our acreage of woods. Sincerely, Bill

[@greatitbroke]

I agree with you its really stupid. Only 2 pound foam will keep out water and you cant buy it in a can or from a box store. Its idiotic to say the least.

[@lyndacrockett5362]

I purchased my home 5 years ago it has three 15-year-old oak trees in the backyard less than 15 ft away from the house. I knew when I bought the house I will eventually have to remove these. Now I'm getting ready to paint and dug a trench around the slab. I found roots coming from one of the trees embedded inside slab. Looks like they pump some concrete in there at the corner of the house where the tree roots entered the slab meaning they knew about this before they sold the house. At any rate the roots are only as big around as my thumb at least the ones I can see. I cut the roots and called an arborist because in my city you can't remove an oak tree without the permission of an arborist and a permit. The local arborist came over and said oak tree roots inside your slab can do no future damage to your home or plumbing and therefore refused to allow me to take out this dangerous tree. I had to call another arborist from far away. I took pictures of the roots in the slab and sent them via text message to the company before they came. I also told them I'm taking out this tree whether you agree or not so don't waste your time coming if you don't intend to help me or you're more concerned about the tree than you are about my house. Don't get me wrong I love trees. How the city could allow a guy to build a new house within 15 ft of new trees that he put in that can grow upwards of 30 ft is beyond me. Either way the arborist number one treated me like a criminal. All three trees are absolutely covered in carpenter ants. But they look like healthy trees I don't see any damage or holes or dryness anywhere.

[@arboristBlairGlenn]

Smart decisions can prevent a future problem

[@mikeharrington5593]

Don't give me problems, give me solutions !

[@arboristBlairGlenn]

To come up with a solution One must first understand the problem. What I “give” you Is knowledge. What you do with the knowledge is up to you.

[@rubybackert3612]

You need to go a little further on some solutions to the holes you were dealing with. Please add what you would do next after cleaning out the dirt and leaves, etc. Thanks.

[@arboristBlairGlenn]

That’s the problem. Not much more you can do that doesn’t make things worse or of no value. Sorry

[@arboristBlairGlenn]

Dr Alex Shigo (Wikipedia) Early in his career, the first one-man chainsaws became available. These enabled him to prepare longitudinal sections of trees, which allowed him to study the longitudinal spread of decay organisms within them. A major discovery from this work was that trees have ways of walling off decaying tissues, which he named Compartmentalization of Decay in Trees (CODIT). This led to reassessment of arboricultural practices such as pruning techniques and cavity treatments, which showed that many then current practices (such as coating cuts with tar) actually promoted decay or were ineffective. The ANSI A-300 Pruning Standard reflects his recommendations.

[@gristlevonraben]

I hope to find how to fix it properly

[@arboristBlairGlenn]

Sadly, there isn’t any thing we can do to “fix” it. But we can make things worse.

[@gristlevonraben]

@@arboristBlairGlenn I guess so. lots of people on youtube that repair trees are using concrete instead of foam, but some parks are recommending foam. seems like the concrete tree repairs are doing okay over time.

[@arboristBlairGlenn]

Gristle Von Raben only way to know is to dissect the trees. I have quite a few videos on what I find. Theory’s are one thing but seeing is believing.

[@gristlevonraben]

@@arboristBlairGlenn ok. I just have a pretty maple tree and hope I can stop the decay and that's why i asked. Maybe one day someone will invent a compound, like they do with human bone implants, that trees will stick to and can be used to seal them up. have a great weekend, Sir.

[@arboristBlairGlenn]

Gristle Von Raben 😊

[@rickreno2492]

I vote Blair for city arborist !!! He’s the Best !!!

[@arboristBlairGlenn]

Rick Reno thanks but that is not a job I care for

[@jenniemikita5151]

Your not saying what we should do?

[@arboristBlairGlenn]

Sorry, but there is no “fixing” a cavity. Leave it alone.

[@andyinthevalley9900]

You keep saying to leave it alone so you can do future inspections which are not possible if filled with anything. Then why even inspect if you will just keep leaving it alone?

[@arboristBlairGlenn]

Because the tree is on someone’s property and the future liability or decision to remove can be evaluated. In other words, filling it does not help. Leaving it open is not a repair, just a way to inspect.

[@General_reader]

Couldn't you just tar the foam once it's dry??? Making sure bulge is large enough to allow water run off.

[@DavidEspenlaub]

I disagree with some of your comments. Foam will keep out leaves and prevent pooling. It will not keep it dry inside. Nothing will. The tree can absorb some moisture. The presence of the plant does not necessarily mean the moisture level was harmful. It surely was better than 3 or 4 inches of leaves and water.

[@douglasreid6480]

The joint is a natural feature of the tree. Natures remedy is that it fills with water and becomes tannic acid that prevents decomposition.

[@arboristBlairGlenn]

It is more about decay not forming in an anaerobic state.

[@lovera3878]

I was about to plug a hole. But I see that by doing do the moisture will stay in. I will kill the ants vacuum or blow debris away and keep an eye on it. So many schools of thought. They all sound great. I will use tanglefoot to keep ants away and see what happens

[@arboristBlairGlenn]

carlos lovera good luck

[@readysetsleep]

A classic from 1997 kzbin.info/www/bejne/iGeUnql9nK2Dh80 I didn't even know they had urban forestry rangers back in the 1990s, and they they used foam too..