Hollow veteran Linden (400yr+) - recommendations?

POOT

New Member
Location
Oslo
Hi all,

Thought I would make a quick post to get some input for a veteran linden that's hollowed out at in-laws property in the south of France(provence). I don't live in France, so getting the job done is another question for another day. (I'm a landscape architect, but worked a few years as groundman mostly)

Tree has an old steel collar from years back that's cutting into the cambium, and definitely needs to be removed, but there is an open question on whether bracing or cabling (dynamic/static) or another collar would work to keep the trunk stable. There's not much risk to the house, and it's got great growing conditions. They are out in the country and had some pruning done by a gardener recently, and more heavily when the collar was put on, but I couldn't see what was done through the growth while I was visiting.

Tree stats:
DBH - ~2m (6'6")
circumference - ~ 6.25m (20'6")
possibly t. cordata or t. tomentosa

growing conditions: Mediterranean climate- full sun, plenty of available groundwater, moderate shelter from wind in the surroundings


I'm not too bothered by the hollowness, as I've seen a fair share of veteran trees around Europe which get hollowed out with age and start to get more gnarly, but are still healthy just rocking a different look. Still, I also know that the tree needs a helping hand to keep from splitting open - and that the collar needs to come off ASAP (told them to get the work done 2 years back)

I know there are different opinions on how to do tree care, so I'm open to hear what you all think.









POOT
 

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Reach

Well-Known Member
Location
Atglen, PA
My thought would be to get that collar off ASAP, before it completely girdles the tree to death. I’m actually surprised that the tree has grown around it so far without it being girdled yet.

I would have the collar removed by a well regarded arborist, perhaps look and see if the ISA has a presence in the area and find a Board Certified Master Arborist to look at the tree and make recommendations. It’s too hard to make a judgment from a set of pictures on the internet, especially on a tree like that one, but for sure it needs professional help from a truly qualified professional, and not just some guy who says he knows what he’s doing.
 

Tom Dunlap

Here from the beginning
Administrator
Yes, I do know geography!

Contact my friend Erk [Eric] Brudi in Munich. If he can't help you himself he will be able to connect you with the right person closer to you.

This is not an every-day consultation. Lots of reasons to find a well-qualified arborist.

 

POOT

New Member
Location
Oslo
Yeah, my thoughts exactly. I thought they had acted on my advice two years ago, but at least the guy they got to prune it had the sense to not screw with things beyond his pay grade.

These responses are sort of why I posted up here on the forum. My best mate has about 15 years experience in the Toronto area, but this kind of tree requires the specific knowledge of someone who's really worked with ancient trees before. I don't think I've seen any trees this old in Toronto (maybe one or two 250 yr/olds), and not even close for a Linden.

The farm property is actually named after the tree, and the buildings are about 350 years old...so I reckon this tree has easily been around a fair bit longer, given the known growth rates for Lindens up to and beyond maturity. I know aging is impossible at this point, but even in good conditions I think 400 years would be pretty conservative (you can see a 500+year linden HERE), and it's pretty likely they did a hard pruning when they put the collar on back in the day.

Cheers

POOT
 

cerviarborist

Very stable member
Location
Florida, USA
I wouldn't be too quick to blithely remove that collar. It's likely under a lot of pressure with a lot of potential energy just waiting to go somewhere. An arbitrary release could cause a reaction with catastrophic results to what's left of the tree. It's an enviable assignment, and whoever is privileged to work on that tree ought not to be in too big of a hurry to change things without a lot of consideration for reactions and resultant consequences.
 

Tom Dunlap

Here from the beginning
Administrator
My view from 4,555 miles away would be to have a support plan...install bracing in the canopy..use flat ratchet straps around the trunk. use several. slowly loosen the metal band. soak the screws with PB Blaster first. Then turn the fasteners no more than one turn per week. Let the tree realign itself.

I'll put my 4,555 mile view down now
 

27RMT0N

Well-Known Member
Location
WA
I had the same thought. It is very easy to think 'constriction is bad' and generally it is, but this tree seems to have thrived even with the constriction and has no doubt adapted in some way to having that bit of support. The removal of it, especially quickly could have some unintended consequences. ,
 

POOT

New Member
Location
Oslo
I wouldn't be too quick to blithely remove that collar. It's likely under a lot of pressure with a lot of potential energy just waiting to go somewhere. An arbitrary release could cause a reaction with catastrophic results to what's left of the tree. It's an enviable assignment, and whoever is privileged to work on that tree ought not to be in too big of a hurry to change things without a lot of consideration for reactions and resultant consequences.
Yes, I had similar thoughts - even though I know the collar has to come off, doing it too quickly without other braces/etc in place would be a recipe for disaster.

I'm just hoping to find the right people for the job, and Tom has helped a bit with that, since the French ISA directory is pretty slim - which is strange for such a big country.
 

cerviarborist

Very stable member
Location
Florida, USA
I met many competent arborists in Italy at a tree biomechanics workshop I attended there about three years ago. When it comes to veteran trees, you're really looking at a very small pool of highly qualified people, and many of them are accustomed to having to travel to work on subject trees.
 

cerviarborist

Very stable member
Location
Florida, USA
You may want to reach out to Dr. Bruno Moulia, affiliated with Université Clermont Auvergne and INRA, Institut national de la recherche agronomique. Tree Biomechanics and how trees react biologically to loads, is his field of study. He may be able to assist you himself, and he would likely also be able to be a referral resource.
 

KTSmith

Well-Known Member
Am I seeing that the tree is a set of stump sprouts? Tilia grows quickly in the open. I expect the stem ages here and on the Romanian example are inflated by at least a factor of two. Most folks think their large trees must be old. Some are and some are not.
 

POOT

New Member
Location
Oslo
Am I seeing that the tree is a set of stump sprouts? Tilia grows quickly in the open. I expect the stem ages here and on the Romanian example are inflated by at least a factor of two. Most folks think their large trees must be old. Some are and some are not.
No, not stump sprouts as far as I could tell when I was there in person, though it seems like there was heavy pruning some time back since there are no large lateral branches. I know aging trees is difficult, but I also know that once Lindens hit maturity (~120yrs), and many other trees for that matter, the growth rate is slow even if conditions are good. I've seen bigger girth close to 10m on some veteran Oaks in England (800yrs+), but for a Linden the best information I've seen indicates that a diameter of this size would be fairly old.

Can't say for certain on the Romanian example, though I know they did coring studies and only afterwards increased their estimate of the trees age from 400 and change to over 500. Maybe they are fudging it for tourism, but not my call.
 

KTSmith

Well-Known Member
Thanks Poot, your experience with Tilia in Europe is deeper than mine. I humbly defer. Actually, it was the Romanian example that set me off. No dendrochronologist would give an age plus/minus anything. Part of the central dogma of dendrochronology is the absolute assignment of the year of ring formation. I know, I'm used to error bars around mean values for, say, chemical composition. Dendro folks don't do that.
 

cerviarborist

Very stable member
Location
Florida, USA
I'm with KTSmith on the tree appearing to be an enormous trunk with a lot of johnny come lately epicormic growth, perhaps due to retrenchment. Regardless of what one chooses to call it, you've got lots of toothpics poking out of a big potato. The idea that there's any branch material strong enough to cable together to protect the trunk from splitting would seem a remote hope. Cabling together Chia growth would no more likely hold a chia pet together.
 

POOT

New Member
Location
Oslo
I managed to get a pic from winter 2013 which makes things a bit clearer and another from 2018 showing front side.

There seems to be big enough branches for cabling in some places, but I'm not sure what the best course of action would be in any case beyond dealing with that collar. Looks like the left side had a large branch taken off to shave weight, maybe when that collar was put on.Girth is probably exaggerated a bit then since the tree seems to have started splitting a long time ago. Might even be another missing section?

However the pruning has been done since, there definitely a lot of sprouting right now. IMG_0136.JPG
 

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KevinS

Well-Known Member
Location
ontario
My view from 4,555 miles away would be to have a support plan...install bracing in the canopy..use flat ratchet straps around the trunk. use several. slowly loosen the metal band. soak the screws with PB Blaster first. Then turn the fasteners no more than one turn per week. Let the tree realign itself.

I'll put my 4,555 mile view down now
I was along the same lines but I’d look at needed pruning, weight reduction, etc If needed before supporting and then loosen her belt off.
As for the pressure I’d bast that tensioner bolt with penetrating oil for a week before I wanted to bring out a wrench. If it unthreaded that would be safer (imo) than just cutting the belt.
 

Daniel

Well-Known Member
I wouldn't be too quick to blithely remove that collar. It's likely under a lot of pressure with a lot of potential energy just waiting to go somewhere. An arbitrary release could cause a reaction with catastrophic results to what's left of the tree. It's an enviable assignment, and whoever is privileged to work on that tree ought not to be in too big of a hurry to change things without a lot of consideration for reactions and resultant consequences.
Makes sense. Put another one on before you let this one off. It looks like they are made to be loosened.
 

Tom Dunlap

Here from the beginning
Administrator
Until a final decision is made Id be up there with some pieces of rope tying things together. maybe a flat ratchet strap or two down low. work towards a final plan while the temporary supports buy you time
 

saucerboy

New Member
Location
Eu
There´s a fairly new certification project aiming at harmonising skills and knowledge recognition in veteran tree management in Europe. It´s called VETcert and on their website www.vetcert.eu you can find a list of french veteran tree specialists both on practising and consulting level. I´m sure they would be happy to help.
 

cerviarborist

Very stable member
Location
Florida, USA
You know, I can't really tell from the photos and video, but I can see significant wound oclusion near one of the trunk voids, which has gone all the way around to the interior. If there is enough of that inside, I wonder whether there may be sufficient vascular transport in the interior of the trunk to service the canopy and roots regardless of that girdling strap. Trees tend to be so ridiculously overengineered that they can lose a lot of functionality and still keep ticking. The wily old ones even more so, since they've sustained a scratch and a black eye or two in various dust-ups over the centuries.
 

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