Fracture pruned induced bud formation from callus tissue

[David Humphries]

After watching and trying to record this phenomenon for a number of years, we finally came across what are undoubtedly adventitious epicormic buds, forming on callus tissue formed on the edges of a deliberately torn/fractured branch.

 

The tree below is a lapsed 350 year old beech pollard which is subject to a cyclical pruning regime to manage down the lapsed pollard poles back toward the bolling. Removing branch weight (which can lead to pollard poles naturally fracturing off the tree due to lever arm and decay issues) whilst where possible, maintaining a retrenching canopy where buds develop lower down and within the existing canopy. This technique hopefully leads to a more stable tree which aims to both continue to exist and maintain a cultural woodland practice and enhance the sites fragile biodiversity.

 

On assessment, this branch had no buds to prune it back to on its last cycle (some 4/5 years ago) so it was sacrificed back to a relatively long stub to remove significant wood weight from the delicate bolling.

 

The fracture was created to expose the maximum amount of potential callus tissue as was possible, without ripping it back to and past the bolling point at the top of the trunk.

 

This practice, (although not scientific and looking like a 'cowboy arborist' has been attacking it with a pole saw) has the potential to offer up additional options to help with the reduction process which can be stretched across decades.

 

 

More buds forming lower down, the better !

 

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[David Humphries]

In an attempt to replicate the outcome above, (whilst the tree was being worked on again this week and on another similar branch which had no option for short linear reduction) we've mimicked the first fracture by creating a new one on the same same side (cardinal point) of the crown.

 

This fracture was created by partially cutting through the top of the branch at a steep angle and carefully pulling it apart with a tag line to get a slow long tear.

 

It will be interesting to see if the fact that the original fracture which was on the north side of the tree (away from UV desiccation) was whether this is the key to successful callus bud formation.

 

As a control, there are other fractures on other pollards facing different cardinals

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[Gary Prentice]

IME these aren't too unusual growing from the callus on 'topped' beechs with internodal cuts but although they're present, growth often appears retarded and long term survival seems intermittent as rule.

 

Maybe 1 in four shoots grow on, the other three sulk for a year or two at the size in your photo's before just dying off. Never thought about why this should occur. Of course its a lot more bleak up north:biggrin:

 

Nicely recorded as always David.

[David Humphries]

IME these aren't too unusual growing from the callus on 'topped' beechs with internodal cuts but although they're present, growth often appears retarded and long term survival seems intermittent as rule.

 

I think this is a given Gary.

 

It's something we looked at fairly closely whilst climbing and recording the pollards in the Basque in 2009 (specifically cuts and regrowth) for Helen Read's Arb Journal paper on "Restoration of lapsed pollards; Evaluation of techniques and guidance for future work" Volume 35, Issue 2, 2013

 

I think what's perhaps important here is the orientation of the exposed wood to desiccation.

Hence the historical mulch mats in one of the attached images.

 

I heard Dr Dirk Dujesiefken talk last year where he looked at some studies at covering natural wounds and pruning wounds with breathable materials to help keep them from desiccating and then observing meristematic tissue forming on the wounds, where they would perhaps dry up and do nothing if left uncovered.

 

 

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[MattyF]

I think this is a given Gary.

 

It's something we looked at fairly closely whilst climbing and recording the pollards in the Basque in 2009 (specifically cuts and regrowth) for Helen Read's Arb Journal paper on "Restoration of lapsed pollards; Evaluation of techniques and guidance for future work" Volume 35, Issue 2, 2013

 

I think what's perhaps important here is the orientation of the exposed wood to desiccation.

Hence the historical mulch mats in one of the attached images.

 

I heard Dr Dirk Dujesiefken talk last year where he looked at some studies at covering natural wounds and pruning wounds with breathable materials to help keep them from desiccating and then observing meristematic tissue forming on the wounds, where they would perhaps dry up and do nothing if left uncovered.

 

 

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Interesting stuff.

[Kveldssanger]

Interesting stuff.

 

Absoutely. Nice shots of the new shoots. Hope to see an update in a year or two.

[treeseer]

Thank You David! I've waited for years to see that evidence. As Gary says it's not overpoweringly vigorous, but it's a start!

 

I'm still inclined to cut to nodes, as was done here in 2002; pic taken 2010.

Sprouts from dormant buds are bound to be better anchored; this one held up 200#! I'd have been in a bad way if it had failed.

 

Yes drying would be a primary consideration with epicormics, as light may be for endocormic (from dormant buds) sprouts. But this 'stub' is in the lower part of the crown, facing east. It may get a little midday light.

 

What would be exciting would be to add some 'scientific' cuts to buds into your experiment. I'm not sure I understand how "On assessment, this branch had no buds to prune it back to..." I see a lot of nodes with evidence of buds on the other branches.

 

The branch in the pic just had bulges to aim for, but it worked out well on that beech branch.

[Stephen Blair]

Have you considered the amount of pressure caused to make the break when comparing re growth?

[David Humphries]

Have you considered the amount of pressure caused to make the break when comparing re growth?

 

Not really Stevie, as there are many variables. Time of year, orientation, species etc......?

 

 

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[David Humphries]

An interesting observation on a Poplar we were working on last week.

A naturally damaged branch (wind event) with the lower callus toward the north.

Buds have broken where the wound is in shade.

 

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