This thread was prompted by responses I received to an aggressive trunk chop - Because I chopped it so low and branches were growing only in two places, concerns were raised that much of the root system would simply die as there are no branches to feed these particular roots. The responses were based on the fact that specific branches feed specific roots and vice-versa, and that once a branch is cut and no branches left in that line the roots will die from a lack of food. This raised a number of questions in my head as we seem to be pruning trees constantly in a way that would effectively cut roots off from their food supply. For example, I am growing out a new leader on a stump and there are a number of lower branches below my intended first branch that I am using as sacrifice branches. When I finally remove the sacrifice branches, I assume that the roots currently being nourished by these branches will no longer have a food source as only the new leader and one branch will remain and I will not be growing out branches that low again. So I guess I'm trying to get a better understanding on the relationship between roots and the branches that feed them in the context of heavy pruning so that I do not kill off roots needlessly by depriving them of the their food sources.
The Relationship Between Branch Pruning and Need for Roots
- Thread starter dbonsaiw
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NaoTK
Chumono
This is a very species-specific topic. Moisture and nutrients can be stored in the trunk/stem and also move laterally within the stem in most species, so there doesn't have to be a direct root-branch connection. It may take time for this lateral connection to set up, on a juniper for example, so you can get root die back if there is no branch in some species. On a zelkova you can have 0 branches and 0 root matter and the energy within the trunk is enough to regenerate both.
When repotting, some folks say to leave more branches as a way of helping to regenerate roots. However the caveat is you still need enough moisture capacity to supply those leaves. If the leaves wilt they could die and the tree may be lost. The conservative thing is to keep the roots and branches in balance, but more roots is always better.
When repotting, some folks say to leave more branches as a way of helping to regenerate roots. However the caveat is you still need enough moisture capacity to supply those leaves. If the leaves wilt they could die and the tree may be lost. The conservative thing is to keep the roots and branches in balance, but more roots is always better.
0soyoung
Imperial Masterpiece
Like @NaoTK said, it is complicated, and it depends.
Give you this example to ponder.
During the previous year I had made an air layer well above the trunk stub that you see. I harvested that layer by cutting the trunk below the girdle. IOW, there was green bark all the way to the cut going into winter. This is how it looked the following fall after I cleaned away the lifted bark.
A pressure gradient exists in the phloem thanks to gravity. When in leaf, the phloem loaders in the leaves produce an added pressure that is sufficient to push carbs upward into extending stems and etc.
Auxin produced by buds also plays a strong role in signaling that there is life above. Without it, cambium cells die, triggering the CODIT process. Auxin (IAA) only moves downward toward the roots on the polar auxin transport (PAT) stream = a bucket brigade from one cambium cell to the next. Auxin is also in the phloem (just a 'series of tubes') and can be off-loaded anywhere it is needed. This is why the cambium stays alive immediately below a girdle during the season = phloem pressure pushes carbs and auxin up toward the girdle and cells in that region then off load them, use them, and stay alive. During the winter, phloem pressure is low as are auxin levels. Variations of these factors exist across species and even varieties/sub-species.
Thanks to PAT roots can exist. PAT allows auxin to 'pile up'. High auxin levels 'up-regulate' cambium cells so that they can form a root meristem that produces yet more auxin that gets recycled. Going counter to the PAT in the pericycle (analog of the cork cambium on stems). If one removes the auxin flow in the PAT, the cells in the root tip down-regulate and it is no longer a root tip and it proceeds toward death, producing things that will trigger root branching and maybe going so far as to cause the tree's leaves to turn yellow and maybe even fall off.
Google scholar is where its at, especially during the winter months.
Give you this example to ponder.
During the previous year I had made an air layer well above the trunk stub that you see. I harvested that layer by cutting the trunk below the girdle. IOW, there was green bark all the way to the cut going into winter. This is how it looked the following fall after I cleaned away the lifted bark.
A pressure gradient exists in the phloem thanks to gravity. When in leaf, the phloem loaders in the leaves produce an added pressure that is sufficient to push carbs upward into extending stems and etc.
Auxin produced by buds also plays a strong role in signaling that there is life above. Without it, cambium cells die, triggering the CODIT process. Auxin (IAA) only moves downward toward the roots on the polar auxin transport (PAT) stream = a bucket brigade from one cambium cell to the next. Auxin is also in the phloem (just a 'series of tubes') and can be off-loaded anywhere it is needed. This is why the cambium stays alive immediately below a girdle during the season = phloem pressure pushes carbs and auxin up toward the girdle and cells in that region then off load them, use them, and stay alive. During the winter, phloem pressure is low as are auxin levels. Variations of these factors exist across species and even varieties/sub-species.
Thanks to PAT roots can exist. PAT allows auxin to 'pile up'. High auxin levels 'up-regulate' cambium cells so that they can form a root meristem that produces yet more auxin that gets recycled. Going counter to the PAT in the pericycle (analog of the cork cambium on stems). If one removes the auxin flow in the PAT, the cells in the root tip down-regulate and it is no longer a root tip and it proceeds toward death, producing things that will trigger root branching and maybe going so far as to cause the tree's leaves to turn yellow and maybe even fall off.
Google scholar is where its at, especially during the winter months.
sorce
Nonsense Rascal
As Above, So Below.
I believe if one could grow a tree in a "perfect" scenario, we would see the top mimic the bottom exactly.
The only reason this doesn't happen all the time, is because there is no "perfect" scenario.
This can't be proven untrue and has proven true in enough instances for me to find this the best starting point for understanding growth.
Enter Crosstalk and how/when pruning top effects the roots how/when, and how/when pruning roots will effect the top how/when.
Also, what we can be actively doing to manipulate this horticultural truth to better suit our design goals.
Base first. Roots first. Support system first.
This is why I am such a large advocate for appropriate air root pruning devices.
It doesn't really matter what the top is doing if the base is in a basket. The roots will be pruned, fork back, and when that entire leg of root is chock full of feeders, yet the tree still needs more root, it will begin to generate them from near the buried base, essentially auto perfecting your radial nebari.
But remember the impossibility of a "perfect" scenario.
Basically, the more "even" the beginning of both top and bottom, the less flawed it's continuation, the less possibility for problems to keep at bay.
A perfectly balanced broom style elm for instance, can almost never be messed up.
Whereas having a rootless log throwing one thick branch up top, creates more of a differential, where that one thick branch will make one thick root that, even in a root pruning device, will become too thick for design before the basket starts working to auto perfect your radial nebari.
Enter the importance of Airlayering to create a good radial nebari on anything with sufficient branching above, "sufficient branching" being a top "radial" enough to correspond with the radial nebari.
Tree species becomes important here.
Again, our friend elm is one of, if not the only tree capable of budding radially around a chop, the best scenario to continue growing a flawless nebari. So top "sufficient branching" on elm is of little concern, as they can mirror a radial layer perfectly.
Where other things need more consideration of what "sufficient branching" above is.
Those pipes and connections.
Enter the Pie Graph, pizza if you prefer.
The smaller the divisions around the pie, the easier it is for a tree to remain ....."fluid".... in it's fluid movement.
A tree with 100 radial roots eminating from the base will be much easier to work, and suppress your stated concern.
A tree with only 4 roots eminating from the base has larger room for error.
It's easier for a tree to reconfigure connections the more divided they are, the smaller the reconnections.
This endeavor IS a race....and what do they say at the beginning of a race?
Gentleman and Danica, start your engines.
The engine in this case is the well divided radial nebari.
An airlayer is that crated, shiny new engine that works better which you get to install later in some instances.
Sorce
I believe if one could grow a tree in a "perfect" scenario, we would see the top mimic the bottom exactly.
The only reason this doesn't happen all the time, is because there is no "perfect" scenario.
This can't be proven untrue and has proven true in enough instances for me to find this the best starting point for understanding growth.
Enter Crosstalk and how/when pruning top effects the roots how/when, and how/when pruning roots will effect the top how/when.
Also, what we can be actively doing to manipulate this horticultural truth to better suit our design goals.
Base first. Roots first. Support system first.
This is why I am such a large advocate for appropriate air root pruning devices.
It doesn't really matter what the top is doing if the base is in a basket. The roots will be pruned, fork back, and when that entire leg of root is chock full of feeders, yet the tree still needs more root, it will begin to generate them from near the buried base, essentially auto perfecting your radial nebari.
But remember the impossibility of a "perfect" scenario.
Basically, the more "even" the beginning of both top and bottom, the less flawed it's continuation, the less possibility for problems to keep at bay.
A perfectly balanced broom style elm for instance, can almost never be messed up.
Whereas having a rootless log throwing one thick branch up top, creates more of a differential, where that one thick branch will make one thick root that, even in a root pruning device, will become too thick for design before the basket starts working to auto perfect your radial nebari.
Enter the importance of Airlayering to create a good radial nebari on anything with sufficient branching above, "sufficient branching" being a top "radial" enough to correspond with the radial nebari.
Tree species becomes important here.
Again, our friend elm is one of, if not the only tree capable of budding radially around a chop, the best scenario to continue growing a flawless nebari. So top "sufficient branching" on elm is of little concern, as they can mirror a radial layer perfectly.
Where other things need more consideration of what "sufficient branching" above is.
Those pipes and connections.
Enter the Pie Graph, pizza if you prefer.
The smaller the divisions around the pie, the easier it is for a tree to remain ....."fluid".... in it's fluid movement.
A tree with 100 radial roots eminating from the base will be much easier to work, and suppress your stated concern.
A tree with only 4 roots eminating from the base has larger room for error.
It's easier for a tree to reconfigure connections the more divided they are, the smaller the reconnections.
This endeavor IS a race....and what do they say at the beginning of a race?
Gentleman and Danica, start your engines.
The engine in this case is the well divided radial nebari.
An airlayer is that crated, shiny new engine that works better which you get to install later in some instances.
Sorce
Shibui
Imperial Masterpiece
Stuff travels from roots to leaves and also from leaves back to roots.
The most efficient way for stuff to travel is as straight line as possible so that's what trees try to do - straight lines from roots through branches to leaves and this often means that some roots supply most to the branches directly above.
However problems can occur so plants have developed an emergency plan that lets stuff move laterally if the direct route is stopped. Plants can establish new pathways from roots to leaves but it appears that's not always easy. It appears that some species can do it easier than others.
Whether the change is successful can also depend on time of year and the size of the branch/root - how long the leaves/roots can survive on limited flow until full service can be restored.
In my experience the larger the branch or root that's chopped the greater the chances of a corresponding branch/root declining. The closer a branch and root are tied together the greater the chance of decline after chop. That's often hard to pick but occasionally you'll see an enlarged part of the trunk between a particularly large branch and root under it which seems to indicate a direct connection. I suspect this is where the idea of 'live veins' in junipers comes from. I know I can make a spiral shari on the trunk of a young juniper ana all the branches connected will survive so 'live veins' are not something that junipers are born with but probably develop over many years and may be present in old, yamadori trees especially.
Dead sections of trunk will obviously limit the ability for sideways transfer to set up new pathways.
In short, pathways gradually develop in trunks. Trees do have the ability to reroute but that can sometimes take a little time to get the new plumbing sorted. Not all big chops will result in dead roots/branches. Gradual reductions will allow time for new plumbing to establish.
The most efficient way for stuff to travel is as straight line as possible so that's what trees try to do - straight lines from roots through branches to leaves and this often means that some roots supply most to the branches directly above.
However problems can occur so plants have developed an emergency plan that lets stuff move laterally if the direct route is stopped. Plants can establish new pathways from roots to leaves but it appears that's not always easy. It appears that some species can do it easier than others.
Whether the change is successful can also depend on time of year and the size of the branch/root - how long the leaves/roots can survive on limited flow until full service can be restored.
In my experience the larger the branch or root that's chopped the greater the chances of a corresponding branch/root declining. The closer a branch and root are tied together the greater the chance of decline after chop. That's often hard to pick but occasionally you'll see an enlarged part of the trunk between a particularly large branch and root under it which seems to indicate a direct connection. I suspect this is where the idea of 'live veins' in junipers comes from. I know I can make a spiral shari on the trunk of a young juniper ana all the branches connected will survive so 'live veins' are not something that junipers are born with but probably develop over many years and may be present in old, yamadori trees especially.
Dead sections of trunk will obviously limit the ability for sideways transfer to set up new pathways.
In short, pathways gradually develop in trunks. Trees do have the ability to reroute but that can sometimes take a little time to get the new plumbing sorted. Not all big chops will result in dead roots/branches. Gradual reductions will allow time for new plumbing to establish.
Thank you for all the info. I will continue to explore this topic as it is something important that I have seriously overlooked. In short, pruning is far more than aesthetics and one must have an eye out for the relationship between roots and branches/trunk before just taking saw to tree.
I'm still at a loss on the exact relationship between roots and branches and how this relationship affects the work we perform. Attached is a JM tree I am developing. After the spring chop, shoots grew no higher than 4" off the soil. I am growing the highest shoot into the new leader and ALL lower branches are being kept as sacrifice branches and will be removed in a year or so. I assume that the leader and the sacrifice branches are currently feeding different roots. When I remove all sacrifice branches, the only branches that will remain are the leader and first branch, so I further assume that the roots that were previously being fed by the sacrifice branches will be cut off from their food sources. Is this the case? Will these roots die? Will the maple tree form new connections to maintain these roots?
The second pic is the tree that prompted this thread in the first place. It was also chopped to about a foot and only 2 shoots grew lower down - one as the new leader and one growing perpendicular to the leader. As no buds were popping higher up, I chopped the trunk down to the new leader and folks expressed concern that there are roots not being fed by any branches, thereby risking die back potentially to the root flare and death of the roots.
It seems I am missing something. How can we effectively remove branches from a JM, thereby leaving only one or two branches, without risking death of the associated roots (especially if we don't intend to grow a shoot from the area the shoot was removed from)?
The second pic is the tree that prompted this thread in the first place. It was also chopped to about a foot and only 2 shoots grew lower down - one as the new leader and one growing perpendicular to the leader. As no buds were popping higher up, I chopped the trunk down to the new leader and folks expressed concern that there are roots not being fed by any branches, thereby risking die back potentially to the root flare and death of the roots.
It seems I am missing something. How can we effectively remove branches from a JM, thereby leaving only one or two branches, without risking death of the associated roots (especially if we don't intend to grow a shoot from the area the shoot was removed from)?
Attachments
BobbyLane
Imperial Masterpiece
maples have rings on the trunk where dormant nodes can push from, even if you chop one to no branches, if you chop to a ring, and it has a healthy root system, it should back bud on old wood like most deciduous trees, the more root power the better. I have personally not noticed roots dying off after chopping a healthy tree, maybe the odd one, but nothing that would make me say hey hold on a min, dont do that
ps always thought that was a conifer thing
its true what Shibui said though about trees having to re adjust. I know that if im hollowing or carving a tree, that roots that may have been directly under a substantial branch may need time to re adjust. trees are more resilient and forgiving than we give them credit for. at least the species i prefer.
This part I understand. My question is about when we will no longer be growing any buds from those rings. In my example, the highest shoot is 4" and that will become the leader. The lower shoots will be removed forever and no lower branching allowed to grow there once the sacrifice branches are removed. Other than the first branch, all branches will ultimately grow from the new leader. So what is sustaining the roots that were fed by the sacrifice branches once they are removed and no new shoots grown from the lower rings?
BobbyLane
Imperial Masterpiece
my understanding is that the deciduous tree re adjusts and begins supporting the new area where foliage is growing. but i can also understand how the odd root could die off. seems plausable to me. no risk no reward right
with no branch under the other side of the cut its also very possible you could get some die back on the side where there is no branch. personally, whenever ive chopped maples, its usually a branch under the base of the cut, its what i prefer on most trees tbh. but thats why its recommended on here to seal the cut, to keep everything alive, or give it the best chance.
looks like you have a branch off to the back?
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BobbyLane
Imperial Masterpiece
Heres one of my examples
and if i remember, i did lose a root on the right side, but that could also just have been a result of ground growing who knows.
the wound almost healed too. the radial root system pretty much remained intact.
ps pretty sure Brian has a shohin trident thread where he chopped to one branch with nothing underneath.
its not uncommon or shrouded in mystery
and if i remember, i did lose a root on the right side, but that could also just have been a result of ground growing who knows.
the wound almost healed too. the radial root system pretty much remained intact.
ps pretty sure Brian has a shohin trident thread where he chopped to one branch with nothing underneath.
its not uncommon or shrouded in mystery
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Bonsai Nut
Nuttier than your average Nut
I agree... and I will also add this is where seasonality comes into play - particularly with deciduous. In your zelkova example, the tree will respond very differently if you do the work as the buds are just starting to swell in the spring... versus wait and do the work after the first push of growth has hardened... versus do the work in the late summer. Same work, same tree, but depending on the time of year you may be successful... or you may kill the tree.
I have definitely killed many more trees by over-pruning or otherwise stressing/killing roots, than by doing the same to the foliage mass.
why didn't it bud all along the top cut, or did it and you kept only one?
Going through the other post, perhaps I misunderstood what was being conveyed. It seems that the message was more about the trunk dying back in the absence of branches than about the roots dying in the same scenario. That is, pruning a tree so that only one branch remains (and no more shoots allowed to grow) will risk the trunk dying in the areas not being fed by branches. I assume that in my first example, by the time the sacrifice branches are removed, there will be more branches higher up in the trunk all around preventing the trunk from dying back. In my second example, because no new shoots are growing, there are areas of the trunk not being nourished by branches and will likely die back (thereby ruining what I intended for that tree). It appears I may have learned something.
Your guess is as good as mine. I was expecting branching higher up and just didn't get them. If I had to guess, I would say that my off-season repotting weakened the tree. My other big box maples that I did the same to simply died. This one seems to have powered through at the cost of only growing lower branches. Other than a weakened state, I'm not sure what happened here. I lucked out here as that's what I wanted, but I will pay much closer attention to the health of the tree before repeating this type of blind chop.
Cajunrider
Imperial Masterpiece
For me Root and Top is a seesaw game dictated by time of year, weather, and amount of energy reserved already in the tree. Too much of an imbalance and the game will end with the tree dead. In between there is a lot of fun for us bonsai peeps.
oh, it's that one, the double chopper. Well, I guess you never know for sure.
I like this thread because I used to try the sumo bonsai, and now I wonder if deaths of first chop were due to being dead on one side all the time. The callus would start at the new leader junction and never heal 2/3 for the next chop. There also was a dumb old tutorial I found about widening trunk via uprooting, cutting with a knife halfway up, inserting a rock or stick and replanting while callus closes the gap. I still have one of those, but what a long process, longer than letting it grow.
The bonsai techniques we find on the internets is perfectly logical until we find it isn't.
Shibui
Imperial Masterpiece
I'm not sure of the technical details of sap flow paths but from experience I see it as an interconnected network of pipes or veins with the vertical pipes stronger than the lateral interconnectors. Sap paths between strong branches and strong roots expand the most direct pathways but there's still some connection to the rest of the network through lateral connections. When either branch or root is taken out the main flow paths reduce in size but the smaller interconnectors still take sap to other parts of the tree. Over time those small paths can expand into larger ones to allow increased flow.
In the case of your maple the tree should be able to start using the bypass interconnector circuits to reroute sap flow after the sacrifice branches are removed so most roots will still connect to the upper tree.
Just be wary of removing lots of large close together branches in one go. Not sure if there's less lateral interconnectors close to branches or something else but when I've chopped branches close together the result is often the chops merging into a single large dead section. Removing branches all round a trunk and not allowing room for sap flow has killed the top of a couple of trees.
Most problems seem to occur when we chop really like the second tree. Imagine the vertical pipes and some lateral connectors in that trunk. Now sap from the left side roots needs to cross all the way across the trunk through the smaller lateral connections to get to the single remaining branch. That branch already has great connections through closer roots so does not really need anything from those far roots which means the small lateral connectors from the far side don't need to expand to deliver sap or receive food from the branch. Maybe there's not even enough lateral connections in that short vertical space, bearing in mind that most movement is up and down.
A fair bit of cambium is now not being supported by sap flow and starts to die back.
My experience is die back is often around 45 degrees. In that low chop example I'd expect to see something like this as a result.
with the upper left side dying, including a couple of roots.
Nothing is certain with living things but I've seen enough cases to know what's possible.
I wonder why the popular books on maples and the like don't address these issues as they are fundamental to the work we are doing. They make it sound as though you prune at the right time and the tree just regenerates and develops the way we want. This is clearly not the case and much more care needs to be taken to ensure that the tree is actually developing the way intended, as opposed to dying back into something else. Perhaps I overlooked it.
Cajunrider
Imperial Masterpiece
I think the books all have sections on how the keep the trees healthy. Then the trees are all assumed to be in healthy state and full of energy reserve before all the prune/chop etc.. When we by special circumstances have to do multiple things such as chopping or root pruning an unhealthy tree with little energy reserve, it is up to us to find the balance of all activities. I've done my fair share of killing trees when I misjudge the balance.
treepirate
Sapling
What time of year are we talking about chopping?
I have poor success rate of trunk chops and have tried both bud swelling in spring and after the first leaves harden off in mid spring....the last 2 maples I lost were on the way to being plate nebari so I know your pain
I have poor success rate of trunk chops and have tried both bud swelling in spring and after the first leaves harden off in mid spring....the last 2 maples I lost were on the way to being plate nebari so I know your pain
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