Beech (Sylvatica) & Hornbeam (Betulus) Thread Grafting

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Background
A month or so ago I began exploring the potential for thread grafting these two 'similar' spp. Scroll down to see the graft and spare the interpretation/justification of this futility! :p:D:p I soon found out that these visually similar spp. are in fact completely different. Genus aside, the usual story, if you look long enough at something, you will get it. But not enough for me, I have to try it! After reading about frosty experiences and disheartening results on Sylvatica, I decided to go about learning more of this tree. A difficult tree in bonsai it seems, but a noble and historic one (UK particularly). I like this tree and I'm up for a challenge (right now anyway!).

Rationale
I would like to keep a Sylvatica and admire it as I do the English Oak and Sycamore (maple) I keep. Both deemed relatively unamicable materials in the deciduous realm. Hard to ramify and big leaves respectively (among other perceived annoyances). I like them though. Thread grafting branches came to me as a solution when projecting the life of a recent Beech stump I planted (my first stump). Assuming it survives, there may come a requirement for lower branches in the event of too many top branches growing and inhibiting growth below. Approach grafting doesn't look as clean initially.

After walking the hills and valleys of the Scottish borders for years I found numerous examples of fused branches on Sylvatica, this one set me off on this (possibly hollow) quest:

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↑Two fused branches that have been cut off and look rather odd↑ Surely if this can happen naturally, it can be done.

Then I started looking longer and I saw. The boundary lines to the properties here have some 80 to 100 year old specimen Sylvatica. The one below was in mast this year, a huge amount of biomass fell and I would have thought it will be tired for the next few years! Some areas inside the drip line were half a foot deep in beech nuts. Walking around the back of this awesome tree I saw multiple fusions! The tree stands on a ~45 degree slope. I thought it may split apart and commit suicide until I saw all of the fusions holding the back on! These are like cables holding it together now:

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20180221_154939.jpg↑The overall opinion is that Sylvatica are more equipped to deal with approach grafts than thread grafts↑ The above exemplifies two natural approach grafts. Very difficult to find any thread graft-esq formations. I would have thought that all fusions in nature must be attained by the approach processes technically speaking. I can't help wonder if grafting pioneers saw these phenomena and thought, that would work. So why not a thread graft? Many diffuse-porous trees will thread graft easily so why does Sylvatica have a dislike to it guys? Are beeches in pots too weak, are the thread scions poorly grown or chosen? The successful beeches in Ireland seem to be periodically ground grown to maintain their vigour. Maybe this cultivar does not do well potted indefinitely.

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↑Here is a completely integrated branch on the same tree↑ Complete fusion of the cambium 360 degrees, total inclusion! This tree receives a lot of wind here from the valley, quite a bit of movement and friction to fuse all of these branches!

Course, the weather and soil plays a large part in the fusions in this area and of course the proliferation of any plant. The climate is doubtless very good here for Sylvatica. The Irish seem to have a similar climate and the masters there have good results, not many of them granted. Not many people there to begin with though. Only the skillful manage to train Sylvatica.

Grafting Experiment
Grafting begins, one hornbeam and one beech were chosen for the experiment. Sample size is small due to time and tree constraints! If this works it will be an insignificant event and far from conclusive. There are too many variables and too little repetitions here. Nevertheless, it must be done and I will take a quiet nod to a random deity if it works! :0)
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↑Here is the hornbeam (Betulus)↑ It is stuck in a corner of the plot and either a dwarf or stunted by weather/poor soil. I'm not sure it is wet enough for it here. It doesn't appear to have been cut back over the years and was planted around 10 years ago. It may of course be a Pendula cultivar, apparently these naturally weep.

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↑Here is the Sylvatica, planted about 10 years ago also↑ Never pruned. My parents own these grounds and they are happy about the energy distribution on this tree. Not ideal and could be stronger without all of the bottom growth, there have never been grazers here so this tree will be slow to close but very strong.

Both of these trees were chosen because they are strong and in a similar area (about 15m apart) and on the morning coffee walk around here so easy to monitor immediately post graft (for any seal or movement issues)! :) The trees are a similar age and get similar wind and light. These are the few main variables that I can justify controlling under my circumstances unfortunately.

I expect being ground grown will give a huge advantage to these trees from the standpoint of these grafts taking. Should maximise results and if successful, one will have to bear this in mind when grafting potted trees in the future.

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↑Main tools for the job↑ Not surgically sterile here which could be a problem. The implements were washed with earth's universal solvent and soap only! :0/ Bits and sticks were new though. The heal and seal is really good and I have had great results with this on cuts in the past. I'm sure it has hormones in it, I wouldn't put this past Bayer! Great formulation, cut and seal and a mass of shoots appear in no time, no drying out and allows the plant to breathe slowly. It seals out water and insects very effectively, disappearing as the cambium rolls over. I have had to reapply on large saw cuts (<5 inches dia.) before. It is flexible, but strong, don't get it on clothes though ha ha ha! Use saliva to stop it sticking to fingers.

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↑Hornbeam first, branch prepped↑ Side branches were removed to promote apical growth pushing more energy to the tip (no absorption from the side shoots). A vigorous branch near the top of the tree was selected to increase the potential for preferential and fast growth/thickening. Closing the graft at the earliest opportunity. These trees are known apically dominant and taking a top branch should maximise the success rate. These buds are much smaller than the beech and easier to thread through a small orifice. Hornbeams are already looking like better candidates for this type of graft to me.

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The smallest possible bit was selected to ensure the least time to close the graft in the event of thickening. The time to close appears to be one of the critical items for the success of these grafts.

..................................... More to come when I figure out how to upload more than ten images .....................................
 

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Hornbeam (Betula) thread graft

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↑Graft in place, used string to secure the branch on three axis with two short cocktail sticks in each side↑ Not ideal and some movement resulting from this method of anchoring will increase the failure risk here for sure.

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↑Tight space, sealant was pushed into any gaps and bonded with the trunk on both sides↑ This part of the trunk will hopefully thicken faster due to the high position on the tree.

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The key seems to be getting everything ready before making the hole, then carefully threading to preserve as many buds as possible. The wound was opened and sealed within a few minutes. Five buds were left on the branch protruding from the sealed hole. This will hopefully ensure at least one survives.
 

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Beech (Sylvatica) thread graft
This graft is more interesting due to the large difference in size of the buds. The bit was stepped up in size as a slightly larger hole was required. I have seen comments on the large buds on beeches being problematic, understandable for sure.
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↑Sylvatica buds protrude at approximately 45 degrees from the stem and they are long!↑ These buds were very carefully tied down to the branch for protection during the insertion. This was conducted in advance of drilling the hole to ensure the wound is open for the shortest period possible. From this experience, it appears best to wind up the branch, this loads the bud from the bottom slowly bending it to the branch. It reduces the damage to the bud overall. There is potential to damage the bud by loading the end (possibly snapping it or creasing the middle). Just like bending branches during wiring, it is possible to feel the buds torsional strength and adjust loading to mitigate breakage. Sometimes it is not possible to get the bud in complete contact with the branch. In a case like this, the winding will smooth the transition to the stem, protecting the bud.

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↑Close up of the apical bud with the folded and protected buds downstream↑ It took a few attempts to secure the twine. This disturbance should have been kept to a minimum to mitigate failure risk and one attempt is optimal. Initially the winding began from the apical bud down (for ease of insertion). However, it appears safer for the buds if the winding is initiated from below the bud.

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↑After drilling a blunt centre punch was used to carefully push short sections of kebab skewer into the wound↑ Important to hold the branch in place but not to crush it. The trunk an stem must be able to thicken and quickly develop growth contact. To ensure the two cambiums fuse the branch only has to touch the trunk on the outer surface (not the wood inside, just the cambium). Crushing the branch inside the wound may cut off the sap supply or cause damage, promoting corking of the branch and resulting in die back.

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↑One bud can be left on each side of the trunk to give optimum potential for thickening↑ Four buds were left protruding to maximise viability. The trunk itself and forks downstream of the scion branch were prepared before hand also. Selected branches and buds were removed to promote growth and thickening of both the scion section and this trunk area in the coming season. The trunk area is near the top of the tree to increase the likely hood of this graft taking. Growth nearer the top of the tree should be stronger than anywhere near the bottom on this apically dominant species. Many long healthy branches were left in close proximity to the graft point to facilitate healing. Only branches upstream on the trunk can be considered to significantly contribute to healing. All downstream branches (below the wound) will be shipping the majority of their sugars to the roots away from the wound. Taking consideration of the above, branches deemed to potentially shade the scion (when in leaf this year) were removed or cut back.

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↑Not all buds are equal↑ It was noted that not all buds on the beech were the same size and a branch with larger and fatter buds was selected as the scion. These buds are far more beautiful than hornbeam! :)

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↑Sealed immediately↑ Sealant was applied into the wound and checked for a number of hours afterwards to ensure that no gaps developed during the sealing and curing processes. Sealent was added to this graft a second time here as a small gap opened up within the hour. This was due to a 'bubble' of sealant bursting from what I could gather.

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↑This sealant is quite a low viscosity liquid formulation and seeps into all cracks before it finally cures↑ It contains alcohol which ensures a fast cure and kills bacteria. It also has some antifungal properties. A soft flexible structure is maintained when cured due to the resin constituents.
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↑The angle of the dangle↑ The final graft angle is facing South for the sun. This bend in the scion branch is not ideal and it should ideally be spread over a larger section of the branch. Securing the branch with string is another possible point of failure for this graft. The branch naturally lay crossed over approximating this position. However, securing the whole branch with wire or a stake would have been a better option. There is minor movement here though and it moves with the trunk. It is hoped that any movement will be taken up by the sealant and not cause too much internal damage before the graft closes.
 

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........................................ Both Grafts Started in February 2018 ........................................
 

Aiki_Joker

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No problem, it is a good record for me too. Let me know what you guys think. Would appreciate any advice or comments on the procedure. Is there anything critical that I overlooked or mis-prioritised here? Only limited resources unfortunately and had to prioritise some stuff over others. Hopefully nothing critical to success.
 

Danny Tuckey

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What I don't understand is how does the main tree supply water and nutrients to that branch when you cut it off.... Does the bark disappear to expose the xylem and then the transpiration stream carries it through? As I imagine it the bark is like a barrier so how does this work exactly if you don't mind me asking.
 

TN_Jim

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Thanks very much Akia. This is clean.

on the verge of (grafting) is all very new..this is very interesting to me, never done a one but this is my understanding, please let me know if I have run afoul.

@Danny Tuckey this may not help at all or answer your question, but xylem and phloem are tubes that transport water and nutrients..much like our arteries veins capillaries.. but a tree has two hearts, that are heart and lung combined of sorts, taking elements and compounds as is or changing them to the constituent parts or combinations needed..(phloem: leaves ((sugars (((CO2)))), elements, and compounds)) goes down ; xylem: roots (goes up ((water, elements, compounds (((oxygen))))...xylem is closer to the center of the tree, phloem to the out in the vascular cambium (sugar/leaves)...

callus cells are like stem cells, they are cells with no program and will become whatever the plant needs -xylem, phloem, who knows, wild card cells tree plays..callus tissue is what binds the graft naturally when it touches and knows itself and seeks to mend...

bark is just the protective dead outside...like hair or a shell... I think phloem will eventually become bark, and xylem (secondary) will eventually become wood as the tree creates new cells and gains strength and age by filling in those old lignin supported heart/lung tubes

so cut the phloem..the tree panics and sends out new roots (callus tissue) but still gets water up top -airlayer, cut them both and insert native tissue, callus bonds to the xylem and phloem of new tissue creating an adventitious bridge/ new branch
 

TN_Jim

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...and the branch meanwhile is full of stored energy ready and willing to return hormonal cues...its still alive after you cut it off...like a vase of flowers still booming blooms even though they will likely never produce viable seeds...the whole point of it all...or why you remove or trim back to one or two leaves of a cutting, the leaves don't turn off, they keep ripping an oxygen off of molecules of H2O with the power of the sun even if there is a surplus of water around or not...the hydra fights to the death
 

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Indeed the trunk cambium (undifferentiated cells) grows around the new branch cambium as the branch expands it crushes itself in forcing the cambium to fuse.

The issue comes if the bark is very thick on the scion and prevents the two cambium tissues from union.

This happens in nature too and causes a potential safety issue with co-dominant stems (twin trunks) whereby bark is included in the union and makes it weak. Included bark is pretty on the milling table but not in amenity woodland or parks ha ha ha. Trunks easily split away from each other as they expand and grow. Included bark is easy to spot because calloused tissue should bulge and often crust at the union. If the tissue isn't bulging then the branches/trunks are not fused.
 

Aiki_Joker

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...and the branch meanwhile is full of stored energy ready and willing to return hormonal cues...its still alive after you cut it off...like a vase of flowers still booming blooms even though they will likely never produce viable seeds...the whole point of it all...or why you remove or trim back to one or two leaves of a cutting, the leaves don't turn off, they keep ripping an oxygen off of molecules of H2O with the power of the sun even if there is a surplus of water around or not...the hydra fights to the death
It should be cut when the union is complete though. If cut too early it could be disastrous. The tissues have to sort themselves out before it is cut off for maximum success :)
 

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Thanks very much Akia. This is clean.

on the verge of (grafting) is all very new..this is very interesting to me, never done a one but this is my understanding, please let me know if I have run afoul.

@Danny Tuckey this may not help at all or answer your question, but xylem and phloem are tubes that transport water and nutrients..much like our arteries veins capillaries.. but a tree has two hearts, that are heart and lung combined of sorts, taking elements and compounds as is or changing them to the constituent parts or combinations needed..(phloem: leaves ((sugars (((CO2)))), elements, and compounds)) goes down ; xylem: roots (goes up ((water, elements, compounds (((oxygen))))...xylem is closer to the center of the tree, phloem to the out in the vascular cambium (sugar/leaves)...

callus cells are like stem cells, they are cells with no program and will become whatever the plant needs -xylem, phloem, who knows, wild card cells tree plays..callus tissue is what binds the graft naturally when it touches and knows itself and seeks to mend...

bark is just the protective dead outside...like hair or a shell... I think phloem will eventually become bark, and xylem (secondary) will eventually become wood as the tree creates new cells and gains strength and age by filling in those old lignin supported heart/lung tubes

so cut the phloem..the tree panics and sends out new roots (callus tissue) but still gets water up top -airlayer, cut them both and insert native tissue, callus bonds to the xylem and phloem of new tissue creating an adventitious bridge/ new branch
Cambium produces everything. There are two layers of cambium the zylem never become the bark. The bark can be considered a separate cell morphology produced by the top layer of cambium tissue. Some spp. exfoliate more heavily than others but all and constantly generating bark as they expand. Beech of course is known for its low turn over rate (people carve stuff into the bark and it stays around for a long time).
 
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Aiki_Joker

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Here is a slide. The cambium produces bark on the outside and sapwood on the inside. Multiple layers of cambium cells but can be thought of as the inner layer (producing zylem) and outer layer (generating bark). As Jim said :)
Screenshot_2018-06-18-00-15-25.jpg
 
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TN_Jim

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Good stuff! Thanks for being so thorough.

I am looking to layer an American beech and a hophornbeam, so seeing this thread was/is very helpful.
Please keep us updated.
 

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Good luck with the layering Jim. If you get the right one you can save a lot of development time :)
 

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Good stuff! Thanks for being so thorough.

I am looking to layer an American beech and a hophornbeam, so seeing this thread was/is very helpful.
Please keep us updated.
I would be interested in a hop-hornbeam if you end up with an extra you would like to sell.

Here is nice one I got to work a couple of weeks ago at our study group.
2A21A8E7-C8D1-4AFD-9841-AA1C4CB6AF91.jpeg
 

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