How to fix a tree with a split trunk from wind damage

December 15th, 2009

Readers of this blog will know that my favorite tree is my forest pansy redbud, indeed the related posts you’ll find at the bottom of this missive will point to the other blog posts where I have mentioned it. I love this tree because it has spring interest, in the form of the standard pink redbud blossoms, but it also has a somewhat unique purple colored leaf that creates nice interest in the summer as well.

I wanted one of these probably for 2 years before finding and buying one, and then, back in early October, disaster struck! A wind storm heavily, heavily, damaged the tree. Splitting the trunk in two places.

In retrospect going out and looking at the damage, it was bound to happen, the tree had grown so well that some limbs obviously outweighed the strength of their junction with the trunk, it should have had some preventative pruning done, but I was busy being a new dad.

Some people, when a tree is damaged like that, would just cut it down. If they think it’ll never be perfectly shaped again, they don’t want it. I personally think a tree that survives damage will have more character and be more interesting, plus, I did say it was my favorite tree, so I decided to repair it.

When faced with this sort of damage you really have two options, you can try to mend the split, which is possible when it is a 50/50 split or close to and there is still substantial amounts in tact on both sides. Or, if one side is severely weaker, it may not be able to be saved and so you’ll have to trim it up and make it as clean as possible. I had to do both.

The picture above is of the upper trunk split, this one you’ll notice is really severe with no structural integrity left on the right side. Trees do all of their physiology in the thin green moist layer right beneath the bark (xylem, cambium, and phloem layers, sometimes just called cambium) so if there isn’t enough bark area left to sustain the split branch, it’ll die. If you’re a few hours or a day after the damage and the leaves are wilting, you’ll know there isn’t enough cambium left. You might be able to do some heavy pruning so that the remaining foliage is better matched to the remaining cambium, but chances are you just need to cut the limb off.

So, for the damage shown above, the leaves were already wilting and the structure was so obviously compromised, so I cut the limb off, as cleanly as I could.

The above picture is of the lower trunk split. This is the first branching point of the trunk, the first main scaffold branch split off. In this case though the prognosis was much better, the leaves had not wilted in the least (and I was easily 8-10 hours after the storm) there was still structure integrity to the branch (it was hanging parrallel to the ground, not drooping all the way) and the split was probably 40/60. So I decided to fix it.

The first thing I did was some severe pruning to reduce the weight load of the branch. This branch had grown significantly during the summer and really weighed too much, I probably took off 70% of it’s mass. Just so I could lift it back into place as much as anything else.

I temporarily tied the branch up with twine, temporarily for a few reasons, namely because if you tie a tree you choke it. People run into this all the time with birdhouses. They do not want to “hurt” the tree so they use rope, twine, or wire (the worst) to tie a bird house to a tree. Really, the better thing to do is just to nail it. A tree can survive a puncture wound no problem, but if the tree grows into a rope or wire it’ll impede the flow in the cambium layer and choke it.

After the tree was in place I got out my power drill and bored a hole through the tree at the site of the split. Then I went down into my basement and looked through my screw/nut/bolt/nail organizer. In a bin called “toilet parts” I found some large brass bolts, these were perfect. Brass doesn’t rust, and being an alloy of copper it may have some antifungal properties. I put a large bolt through the hole and secured it.

I then drilled another hole a few inches above the split and put a longer bolt through there. I made sure the hole was slightly smaller than the bolt so I really had to shove and pound it in (thus making sure there would be no gap) and then I used a wrench to tighten nuts on both.

My tree was now a cyborg, and the actions I took may seem severe, drilling two holes, but as I said, trees can survive puncture holes no problem. There was another flap of torn bark and I actually brought out my nail gun and put some brad nails into that, more wounds, but the tree doesn’t mind them.

Eventually the tree will grow over those metal rods, incorporating them into it’s structure, and being all the more stronger for it, with no adverse damage, because they go through the cambium layer, not around it.

So, weight removed, gash mechanically repaired, now I had to worry about insects and diseases. I had both a can of tree pruning sealer and a can of natural shellac wood sealer. I had just read an article saying shellac was better than the other stuff and so used it. Shellac is an all natural waxy resin made by insects and used in everything from wood products, to food, to pills. You probably eat a little bit every day, it is harmless, but it seals wood good. Insects and diseases love open wounds and so it was important to seal the tree with something.

That taken care of, the last thing I needed to worry about was water. Just like with concrete, water can get in a crack, freeze, and then widen and make the crack worse. Even with the shellac the force of water expanding as it freezes was a potential hazard. What I eventually did, though which is not shown in the picture, is just put a bead of silicone caulk around the top of the crack (but not the bottom) preventing any water from seeping in, but if any does, still allowing it to seep out. Silicone is a neutral and inert substance and the tree will probably grow around it fine, or, after healing has progressed, I can take it out. Another option would be to wrap the tree in some sort of plastic, but that can hold in moisture too close to the bark and promote rot, I think my caulk solution is best.

I’ll post an update next year to show how the tree is doing.

Should you repair every tree? No, you shouldn’t, if there is a safety issue where the tree overhangs a structure or is where people often sit, walk, or play, you should always err on the side of safety. If the tree limbs are too big for you to manage to put back into place, you may not have to cut the tree down, but you’ll need to remove the limb. But, if your tree is not yet too large to manage (mine was only about 10 feet tall) you can try to repair it. It doesn’t need to be a total loss.

53 Responses to “How to fix a tree with a split trunk from wind damage”

  1. Cool Garden Things  Says:

    My dad had an orange tree split after hosing it down with water during an ice storm….don’t ask…he learned his lesson on that one. But he did something similiar but also used some gorilla glue and I wonder if the glue was a bit too much…I have not checked on tree yet.

  2. Mom Taxi Julie  Says:

    I have a landscaping book that calls for Forest Pansy Redbuds. They are kind of hard to find! A local nursery said they have them (although I didn’t see them anywhere when I visited) and they are $100 each. ouch.

  3. Matt  Says:

    Have you done this before or is it an experiment? I’d have thought there would still be a strong chance of infection.

  4. Administrator  Says:

    This was my first time but I wasn’t exactly shooting from the hip, I’ve seen it on TV and read various guides on doing it.

    I sealed all holes made with the shellac.

  5. garden  Says:

    Its great advice but having a metal nut/bolt incorporated into the tree is extremely dangerous to do in case someone tries to cut the tree down in the future with a chainsaw. Old nails and metal wiring is a common cause of very serious accidents to workers using chainsaws. Another option I used before is to put a strong ratchet strap around the tree and tighten. This can normally be removed after approx 2 or 3 years depending on the weight and diameter of the broken trunk.

  6. Joseph Tychonievich  Says:

    I’ll be interested to see how this turns out — keep us updated.

  7. Zack  Says:

    I would use the wind damage as an excuse to prune it.

  8. Administrator  Says:

    I didn’t think about the chainsaw problem, that would be dangerous.

    On the otherhand, I don’t plan on ever cutting the tree down. I’ll just have to remember.

    And I don’t think a strap would work in my case, the limbs were too supple to stand up to that kind of force and it was at a V so the strap would incessantly slip down as it was tightened. Plus, you’re pressing up against the bark, holding moisture against it, etc.

    For a really big tree though, a strap like that is probably your best bet (because it’d be too big to bolt anyways).

  9. LandscapeConnect  Says:

    I never would have thought about the nails in the tree being a safety hazard. That’s something I’m always going to think about when I’m taking down a tree.

  10. martin Wheeler  Says:

    What is the best way to fix a split in the Y of a red maple tree. The tree is 6 years old. Which is the best idea: (1) 6-8 inch clamps coved in thick pipe insulation to prevent bark damage and clamped around the tree 2.wide rachet straps serving the same purpose OR (3.) drilling [a] hole(s) completly through the tree and bolting the tree back together using large washer at both end of the bolts. Should the washer be made of brass due to its anticrossive and antibacteria properites? Could using clamps or straps strangle the tree?

  11. Administrator  Says:

    If you’ve read this post you know my thoughts. If the tree is young enough or small enough that you can use a bolt, I’d use one.

    Anything that is pressed up against the trunk of a tree for long periods of time will wound it and could trap moisture next to the bark which can allow fungal infections to get hold. Even with pipe insulation, as the tree moves in the wind that’ll rub and blister. And any such strapping around a Y will tend to slip down anyways.

    You could try a strap if you don’t want to drill, inspect it after a week maybe. You can always undo a strap (but drilling is forever). For such a young tree though, I think you’ll be drilling. The bark is thin, the branches are supple, I don’t think it’ll stand up well to a strap.

  12. Craig  Says:

    Thanks for the tips – my kids were climbing my favorite tree in the garden yesterday, and split a large branch – I followed your advice, and bolted twice, once above the vee and one right through the middle, and sealed the lot up. I’ve set up a temporary strapping brace, as well as a crutch support for the bough. Now it is wait and see it it works – so far the leaves don’t seem to be wilting, and there was a fair amount of bark that didn’t tear, and I’m really hoping it can be saved. Is there any advice on feeding the tree while it recovers that could assist with the process?

  13. Lisa  Says:

    I have a large (approx. 40′ tall) Juniper tree that has a crack in the trunk, starting at the base and going up about 5′. The crack is about an inch wide and almost 10″ deep at the base, 5″ toward the top, til it ends. I really would hate to loose this tree. Is there any hope?

  14. Administrator  Says:

    That is a really big juniper.

    The crack starts at the base, but then terminates at the top?

    Does it start above the ground or below the ground?

    If it starts below the ground you may have a rot or other issue below ground.

    But if it starts above ground, goes for 5 feet, and then stops… that shouldn’t harm the tree too badly. It is technically no worse than what male deer do to trees every year.

    The more important thing is to identify what, if anything, is causing the crack, and try to deal with the cause.

    You could also use the bolt solution mentioned above ti help prevent it from getting much wider or higher up the trunk. You will need to find some very large bolts though.

  15. Lisa  Says:

    I don’t believe the crack starts underground, but I’ll check it out.
    It was suggested to me that I fill the crack with plain portland cement to prevent insects access, but I’m not sure how I feel about that. I think the shellac may be the better way to go.
    I’m also planning on removing two large branches from the side opposite the crack, which is the windward side. This will balance the growth on the tree, I just hadn’t removed them because I like the wild look of the branches framing my view.
    Any thoughts?
    Wish us luck! (Me and the tree)

  16. Bill Fuchs  Says:

    We have a muli-stem paper birch, approximately 25′ tall, 3 major stems. During the ice storm 2 months ago, the one stem bent almost to the ground. Next morning removed ice and snow and it appeared to return to 10′ off of the ground.

    However, during spring cleanup today, I noticed an approximate 12″ long by 1/2″ twisting split that is approximately 4′ off of the ground.

    I like the idea of bolting and am thinking of using stainless steel, as it also does not rust.
    As the split is similar to a tear, should I fill this with shelac or polyeurathane prior to bolting?


  17. Administrator  Says:

    I would not want to put shellac, or especially urethane in a wound which you hope to close. Use it only to seal an area of torn bark that will be exposed.

    I wouldn’t use urethane even on that though because it is not a natural substance and I don’t know how it might affect the tree. The last thing you’d want to do is poison the tree.

    With a tear or a split you hope that eventually the two parts grow together, and if you create a barrier between them you’ll hinder that.

  18. gardener girl  Says:

    What are you guys thinking, putting bolts and straps and shellac on a tree?! I’m amazed at the abuse people put their trees through. The tree will do just fine with a little, or a lot of, judicious pruning, and let nature take its course. There is a lot of good info out there on how to keep a tree pruned for its long term health. BTW, your tree will probably be around a lot longer than you will, and you might consider what someone else would do with it a hundred years from now!

  19. vanrijn  Says:

    I’m lucky enough to have two Forest Pansy Redbuds. I planted them in Fall 2008. Last night we had a severe thunderstorm. This morning I noticed the larger tree (which is more exposed) was leaning. At first I thought it was the weight of the rain on the leaves (it was still raining). But it hasn’t straightened back up. It seems like the canopy may be too heavy for the slender single trunk to hold upright. What would you advise? I don’t want the tree to snap!

  20. Administrator  Says:

    I would prune yours vanrijn. I should have pruned mine as the growth got too heavy for the wood.

    Trees will often end up temporarily bent because of wind storms, but they straighten back up on their own with time.

    It sounds like that isn’t the only factor for you though, your canopy may be too weighty. Best to err on the side of caution lest your tree end up like mine did.

  21. Gordon Oettel  Says:

    We had bad winds last night and discovered our large Locust tree was split down the Y. It’s probably 40+ and a beautiful tree, so I’d rather not lose it. However, it is about 2+ feet in diameter. Is that too large for this bolt application? I could used threaded rod with plates and nuts.? Any suggestions?

  22. Mary B  Says:

    It’s been a year and a half. How’s the tree doing?

  23. Administrator  Says:

    Not well, leaves never grew on the weaker sides of the splits, I ended up cutting them off. Redbuds prefer some shade, and mine is in full sun as well, couple that with a dry july/first part of august, and it isn’t doing too well. Last year the higher foliage shaded the lower stuff, this year with so much foliage being gone, that isn’t happening. It’ll be a long recovery I think.

  24. Tall55  Says:

    I have a Moptop robinia that was accidentally cut with a chain saw about half way across the trunk (which is about 15cm diameter) well below the graft. Any suggestions as to what I could put in the gap? I would really like to save it as it is a great shade tree in the summer.

  25. Brian  Says:

    Back in 1965 when I was about 8 years old, my father did something that was unheard of and actually quite clever when after a lightning strike, one of the 12 maples that surrounded the property was split in half. Although the tree wasn’t fully grown, it was mature. My Dad enlisted the help of my handyman uncle and together they pulled the tree back together with a couple of 3/4″ diameter steel bolts with flat washers and nuts. As the years went by, the heads of the bolts and the nuts completely became engulfed by the bark and the tree survived with the other eleven for at least thirty years. Eventually all were felled by wood borers but I’ll never forget how impressed I was with my Dad for saving that tree with hardware and elbow grease! It can be done!

  26. Kevin  Says:

    Am trying to bolt trunk of large red maple. Not fully grown but large and wanting to do what I can to bolt at or near base where split has been growing. Can anyone tell me what type of bolting to use? Do I use a screw bolt or just run through and put on washers and nuts on either end of where bolted thru? Is one better or worse than the other?

  27. Sarah  Says:

    One of my favourite small Japanese maples just got badly split by heavy snow on one of the main(2) branches… am reading this with interest! Does this type of mending work for this type of tree?
    For now I have strapped the tree and am waiting to see what the weather brings.



  29. Rob  Says:

    How’s your tree doing?

  30. Heather Sansom  Says:

    The recent storm gale force winds in Queensland (Australia) has taken out our much-loved 3 metre high Grevillea Orange Marmalade which lines the driveway along with five other shrubs of the same species.

    The force split the trunk ast ground level and carried the broken off section about 10m in the wind. This basically took out the whole of the rear foliage and branches of the shrub, leaving only the front half. Before we could get to it this weekend and try and save it, the winds picked up again last night and have split the remaining branches higher up the trunk.

    I am concerned about how to save my tree/shrub without inflicting anymore trauma to it. What would you suggest I do? My husband wants to repair the trauma from last night and leave the tree the base of the trunk trauma to sort itself out. I have tried to explain that in doing that, it could become diseased as it’s broken off below the surface of the ground, and that by leaving only half the trunk in place, future growth would render the tree top heavy, unstable, or beyond salvageable repair.

    I would like to know the best way to tackle the trunk at ground level. Some of the roots are above ground and look to be in stable and strong condition. If we angled the blade and cut it off just above ground, what are the chances of the tree regrowing from the base?

    I can send pictures via email attachment if this would help? And I thank you for any advice you can offer us to save this beautiful native shrub.


  31. Ed  Says:

    I have a flowering cherry tree that has a split trunk from a wet snow fall in Oct with leaves on the tree. Split is about about 1 foot long at the apex of the main branches. Is there anything I can do to save this tree?

  32. Scott  Says:

    Do you have any follow up pictures?

  33. Bridget  Says:

    How did the Grevillea Orange Marmalade shrub do? I think you could always prune the top of any woody species back a bit every season, so as to decrease the top weight, while the trunk of it recovers some structure.

    Aullwood Audubon Center in Ohio had great luck with steel cable run through drilled holes to plates on a huge old Osage Orange that had some huge “branch-trunks” that divided from the main and were in danger of splitting the tree fully down. The tree “ate” its plates and is much more stable with the cables.

  34. Cindy  Says:

    I have a large ash(can’t get my arms around it) and I noticed it was cracked right down the center of the tree about 3 feet. Is there any way to keep it from cracking any further?

  35. Stefan Vittori  Says:

    Yes, How is the redbud doing? I just read your posts since my redbud was split last fall and I temporarily tied it together. I was thinking to bolt the branches and seal the cracks. Thanks for your tips but I wonder how your tree is doing? Can you post new photos?

  36. liz  Says:

    I have a magnolia tree that totally broke in half is there a way that i could save the other half? by maybe regrow some roots..

  37. David  Says:

    Use nylon fasteners.

  38. Linda Wheeler  Says:

    How is the Pansy red bud doing now? We had one split in similar fashion for upper part and trying to figure out if I can save it.

  39. Ted McKenna  Says:

    I have a 30 foot ash with a split main trunk. The tree service trimmed the tree to reduce the weight, and then about 15 feet up, they tied a twin loop harness between two major trunks, just above branches so it cannot slide down, to hold the main trunk together.

    The harness flexes in the wind but holds the trunk together so it can repair itself. Watched on windy days and it works.

  40. Cj Spitnale  Says:

    I have a 3 year old, wisteria tree that got twisted and cracked in middle of trunk near base and another spot in the branches. What do you think would be the best way to save it, if we can? We have heavy wind come through couple weeks ago blew it completely over. :(

  41. Dawn Richter  Says:

    My redbud has a 3 inch split at the v junction.
    I also did not trim it because it looked so healthy but knew i had to soon. When I went to trim saw the split wild. I trimmed it back drastically and tied the split end to a branch above. All of the leave look healthy yet. How is yours doing?

  42. Administrator  Says:

    Tree died awhile ago, it never bounced back and I replaced it.

  43. Dan  Says:

    LOL… sorry but thats funny.
    I am researching how to “fix” a tree crack.
    Some of the sites say buy this and do that…. while others say do nothing, tree’s have been managing this process for millions of years.

    I guess this serves as a good case study…thx

  44. eleen  Says:

    What is the best option to fix a mango tree. The tree is 50 years old. and there was Y around 1 meter from the ground and the tree is split and one half is broken and that was the bigger half. It was not due to wind but the weight of mangos on it. Now there exist a comparitively smaller half but split from ground till Y. What can I do to make it survive?

  45. Rick Wood  Says:

    I have a Globe Willow Tree that has split do to wind damage. I cut some pieces of garden hose, then inserted steel cable thru the garden hose. Steel cable has a tension strength of 800#. I made a loop with the cable, used a come-a-long to pull the Trunk together as tight as I can. I can see splits in the trunk. I have pruned the top one half of the tree. Should I apply some type of Sealant or something in combination. We love our tree, would hate to loose it. Damage is 2 years old. Tree still alive. Help! We live in Western Oklahoma. Very Windy! Thanks, Rick

  46. Rick  Says:

    I have a 20 year old pecan tree that’s about 30′ tall. It has a split in the main V starting at the V and moving down about 3 feet. I will attempt the strapping and also drill 2 holes in the center with large bolts and washers to try and secure it. The tree is still alive and is a great pecan producer. The crack has been there for about 2 years, but it progressively getting worse. Seeing how it’s next to my driveway and house, I’m looking at losing a vehicle or two along with the front corner of my roof if I don’t do something. I hate to cut it down, so I’m attempting a save. If anyone has input, let me know.

  47. Carol  Says:

    During a severe storm, the whole top of a soft maple tree, that came up in our yard 2 years ago, broke off about 3 feet from the ground where I had it staked. All that is standing is the trunk of the tree without a top. Can I prune the broken trunk top & seal it so it can regrow some branches? I know it won’t be as nicely shaped as it was but the little tree has sentimental value to us because of a grandchild born the month we found it growing in the yard so we would really like to save it.

  48. Cindy  Says:

    Help, a windstorm split our very huge and old willow oak where the trunk divides. We got the heavy branches off so the tree would not split and fall on our house. Now we are wondering if we can save the tree. It may be over 100 years old and provides shade and much beauty. Any advice?

  49. Twoertree  Says:

    Do you have a picture after all this time? How did your tree do with the repair you made?

  50. Dale Athanas  Says:

    I have a dogwood that was damaged by heavy wet snow. It had a weak fork to start with so it was easy to see why it broke. The branch was still attached. This tree had a lot of skinny branches and I didn’t think it could survive any more New England winters. Decided to cut it down. Than decided to try to save it. Drilled two holes through the forked section and installed a stainless steel bolt. Had pretty low expectations. That was two years and two winters ago – both bad winters. The repair has held and branches appear to have knit. This year (2015) the tree has exploded with new growth and has turned into a beautiful specimen. I also repaired a broken branch on a Harry Lauder Walking Stick tree with wood glue and a temporary support rope – much to my amazement, that worked too.

  51. Sue B  Says:

    My beautiful Japanese fern tree split in storm today. Because the growth is perfectly ,naturally rounded should I cut this 20 ft tall down and start over or is there some way to save it?

  52. Mike V  Says:

    Snow load caused a 12 foot tall fruit tree to split 60/40 at the upper trunk. I cut off the large branch (40% side) above the split. What is best for the tree? Should I completely trim off the 40% flap exposing the heart of the tree or reattach the flap with screws or some other means to protect the interior?

  53. Administrator  Says:

    They make a spray, sort of like a liquid bandaid, to help protect open tree wounds like that. Find it here.

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