When Trees Don’t Know They’re Dead.

Last week a neighbor of mine called me up to ask how likely it was that their 4 year old (or so) crab apple tree was dead.  Sometime over the course of the winter cute fuzzy bunnies had decided that the tree’s bark was tasty and decided to eat it.  Naturally they ate it all the way around the circumference of the tree with the exception of a strip about an inch wide.  At this point you’re probably asking yourself why the neighbors suspected the tree might be alive.  The reason they were calling me was that the tree was leafing out–  so they figured that maybe the tree would make it — that maybe, just maybe, it wasn’t as bad as it looked.  My answer — Sorry, the tree is dead, it just doesn’t know it yet.  As a rule of thumb you can have up to a third of the circumference of a young tree girdled and the tree has a decent chance of growing out of it.  More than that and, though the tree might live for a few years, you’re dealing with so much damage to the vascular tissue that you’re just putting off the inevitable by not cutting it down.  A tree with as much damage as my neighbors tree had was just going through the motions.

When bark is eaten what is destroyed is the phloem — the tissue which carries the carbohydrates made by the leaves down the plant’s stem.  The cambium — which creates new phloem and xylem — is also destroyed.  But the xylem — the innermost tissue which transports water and nutrients up the stem — is left largely intact.  So girdled trees will flush out in the spring (using resources provided by the xylem), perhaps even two springs, but ultimately the tree will succumb.

But there is an up-side!  Girdled trees will be under a lot of stress.  Stressed trees tend to flower heavily — so enjoy the show first, then cut down the tree.

25 thoughts on “When Trees Don’t Know They’re Dead.”

  1. This happened to me at a commercial property I maintain. The maintenance dept plowed snow basically a ramp for the rabbits to girdle a crab apple tree. It flushed out in the spring but did bite the dust the following year.

  2. It is possible to save the tree by using a bridge graft. You basically restore the cambium layer in a bridge from the two damages sections. And you have nothing to lose trying.

  3. Good Point Jade. I admit that I think bridge grafts are ugly — but they do provide a chance for survival, especially for a relatively small tree.

  4. When working in a landscape crew,I was told to remove a tre that had been nearly girded. Ithad been damaged a couple years ago and the top 2/3 had died. But since the bark strip seemed to show new growth, I transplanted it to my home. I pruned out the dead wood and turned it so you didn’t see the huge scars. It lived for many years as a stunted but cute little tree.

  5. I girdled five invasive Chinese tallow trees (Sapium sebiferum ) on our property. The only one that died was the one we also topped at about 15 ft tall. The others grew bridge grafts and are still doing well two years later.

    We really need to re-girdle and then top them all. Maybe later this year…

  6. (Sorry about the preceding blank.) While you’re on this subject, could you, perhaps, also talk about permanent dormancy. I experienced it when I was a greenhorn at a nursery after mishandling bare-root crataegus, but I also accidentally (and quite fortunately) seemed to have done it to a crepe myrtle too close to my property back in January. It hasn’t quite died, but it has no leaves while the others here in Atlanta are about to flower. Thanks.

  7. Because I manage fruit trees for a living, and mostly those irressistable to rodents apple trees, I see many many girdled trees. On my sisters property in N. coastal CA I actually saw several old apple trees that had been girdled up 4 ft of trunk by goats but continued somehow to survive years later, although I don’t expect anyone to believe it. I really can’t figure out how nutrient is getting to the roots! The trees are in partial shade right by the ocean the there’s not much evaporation going on.

    I’ve also occassionally seen trees build a bridge from where they’ve been girdled right to wood- even when the girdle is completely around the trunk and a couple inches wide. Such trees eventually heal completely

    The point is, many professionals think they can predict exactly what will happen because of what they’ve read and a few experiences of observation, but the real world often contradicts the literature.

    1. Hi Alan,
      From reading your post about the goat bitten trees, I think you’re saying no one did anything to save them, they just healed on their own. Is that correct ?I hope so, because rodents girdled my apple tree (4-5 feet) this winter, and since it’s such a long space I don’t think a bridge graft would work, even if I knew how to do it right. My husband wants to paint some black “tree wound” stuff on it, but I’m hesitant. Some sites say do, some say don’t.
      Thanks for any advice ! Gail on the coast of Maine

  8. Unless you know for sure that a tree is no longer viable to keep around you should leave it alone. If the tree is young you can always move it to a new location.

    Let things happen.

  9. I should have elaborated that apple and pear trees with much more than a half of the bark girdled around the circumference of the base will most often live and completely heal, over time- sorry, but I’ve seen this hundreds of times in my nursery and elsewhere. As long as there’s a decent strip making a bridge the roots will be adequately served for survival.

    I don’t have much experience with other species getting girdled, but I’ve intentionally girdled maples all the way around and had them build a bridge and repair the damage and survive until I came back and did the job again 3 years later.

  10. Many times trees will survive girdling IF they are planted near others of the same species. Root grafts will supply girdled trees with root nutrition. The more evolutionarily remote trees are from one another, the less likely they are to form root grafts.

  11. Thanks Linda, that’s a thought that hadn’t occurred to me. I wonder if those surviving apple trees girdled by goats had roots grafted to other species.

    You are a very astute diagnostition!

  12. @Shawn – I’ve long encountered problems with crapemyrtles when dealing with them while dormant. I go as far as telling people don’t plant them between Sept 1 and bud-break in the spring. Many growers won’t dig them until bud-break anyways. I’ve gotten B&B early in the spring and would often see 50-75% end up in “permanent dormancy”, where they are scratching green, but will not break dormancy. To this date I’ve never lost a crapemyrtle when dug after bud-break.

  13. @Shawn and @Ed – there really is no such thing as “permanent dormancy.” It can be extended, which is the case with many new transplants. If the crown is left alone (which it should be after transplanting), the plant will put its resources into new root growth. When a sufficient root system has developed, buds will break.
    This underscores the reason that it’s important NOT to top prune after transplanting. This forces the plant into budbreak, resulting in a new crop of leaves and a poorly established root system that can’t support them.

  14. Linda, that’s different than what I was taught a couple of decades ago. Then it was that pruning could extend dormancy as the tips signal the roots to begin growth and removing branch tips delayed signalling, thus delaying the beginning of root growth and reducing growth over all.

    The species I grow (mostly prunus and pomes) don’t begin rapid root growth until buds are already growing.

    Carl Whitcomb’s experiments, which I believe began the whole debate about the value of pruning back transplants, didn’t show a better survival rate or more growth of unpruned trees- only an equal growth and survival rate of heavily pruned, moderately pruned and unpruned trees transplanted bare root.

    He advised against indiscriminate pruning, not because it slowed growth or reduced survival, but because it deformed trees without apparent benefit.

    I’m guessing you have some more recent research I’m unaware of and hoping you can direct me to it.

  15. Whitney — Trees tend to flower heavily under stress as a last ditch attempt to reproduce before they die.

  16. Alan, I should have answered your question before — My answer is based primarily on experience in growing and planting trees over the last 15 years. Trees can handle being planted without pruning and will “self prune” if need be. So I guess that means I agree with Whitcomb. I’ve never seen any advantage to pruning before planting — so why do it?

  17. Sorry to comment on such an old post but I’d just add that if the trunk is girdled low enough to the ground that covering the trunk up to where the cambium is intact would allow the tree to grow new roots from the callous tissue that forms there. The tree could even be air-layered after new roots are established to lower it into the soil again…of course that would be difficult on a very large tree but on a smaller young tree it wouldn’t be that hard. Or you could expose the roots that had grown downward and have a tree on stilts.

  18. Eric, I’ve seen trees that have done this – ones that have been planted too deeply and have had to grow a new root system. It works okay as long as there’s not a great demand for water – but the new systems are generally not robust enough to supply water under conditions of high evaporative loss. So the leaves show chronic drought stress every summer when the water deman exceeds the ability of the poor root system to supply water.

  19. I girdled several 3-4 inch invasive cherry laurel a few months ago as well as 3 young oak trees and they are all still alive and well. I wanted them to die. I did about 6 – 8 inches all the way around. One of them I went back and hacked off another layer. To one of them I applied Roundup at the base and it didn’t mind at all. It is still out there waving merrily in the breeze.

  20. hi, I have a very important question.
    we have 5 apple trees which have been eaten all the way round the base. im pissed. can I cut above the root base (root stock) and then take cuttings of the top of the plant and graft them back together for the next year??? anyone ever done this???? pls help me out lads

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