Tree Fork Assessment - Dr Duncan Slater

[stevelucocq]

Hello All,

 

I have just attended the Tree Fork Assessment course run by Dr Duncan Slater. Really interesting and a few light bulb moments for me. http://www.trees.org.uk/Training-And-Events

[David Humphries]

Hi Steve

 

I didn't get to attend any of Duncan's presentations.

 

But there is an interesting discussion already ongoing, perhaps you might like to add your thoughts to that thread?

 

http://arbtalk.co.uk/forum/tree-health-care/102021-understanding-forks-bit-more.html

 

 

 

.

[Arctostaphylos uva-ursi]

Do you care to share the light bulb moments?

[Gary Prentice]

Do you care to share the light bulb moments?

 

Stop removing rubbing/crossing branches, I'd imagine.

[stevelucocq]

For me it just shows again that trees respond their growth to the forces they are exposed to. This fits in with the evidence provided by DR Duncan Slater that rubbing/touching/grafted branches leads to weaker bark included unions as these restrictions reduce the forces on the union and thereby the tree grows to develop a union to only with stand these weaker forces. visa versa if grafts/rubbing branches etc are in place above a bark included union in a mature tree then retain as removing them will greatly increase the forces on the union in one cut and will increase the risk of failure. common sense I know but backed up by scientific evidence which always sits well with me.

[Arctostaphylos uva-ursi]

Thank you for the further explanation Steve. I am struggling to see the difference in the two scenarios you have put forward. To me they seem to be the same. Am I missing something?

[scotspine1]

This fits in with the evidence provided by DR Duncan Slater that rubbing/touching/grafted branches leads to weaker bark included unions as these restrictions reduce the forces on the union and thereby the tree grows to develop a union to only with stand these weaker forces.

 

 

The idea that most mature trees are filled with crossing and grafted branches above included bark unions is utter nonsense. I know this because I spend most days climbing around mature trees. Is the guy Slater proposing that the grafts are created as a result of an included bark union? if so where and how does phototropism fit into that theory? It also implies the tree is a sentient organism which aware of where each branch is located.

 

 

visa versa if grafts/rubbing branches etc are in place above a bark included union in a mature tree then retain as removing them will greatly increase the forces on the union in one cut and will increase the risk of failure. common sense I know but backed up by scientific evidence which always sits well with me.

 

Not really common sense, more common knowledge amongst experienced tree workers, but more so because if you remove one of two grafted/ crossing branches the retained branch is more likely to fail.

 

It's also why 'crown clean' was removed from the most recent BS3998.

 

The thing is - most experienced climbers would never remove large crossing branches in a mature beech for example even if they saw the words 'crown clean' on the spec. The removal of 'crown cleaning' from most recent 3998 was based on the idea that tree surgeons are too thick to make an informed decision about wether or not to leave large crossing limbs (and the deadwood issue)

 

 

.

Edited September 6, 2016 by scotspine1

[Arctostaphylos uva-ursi]

The idea that most mature trees are filled with crossing and grafted branches above included bark unions is utter nonsense.

 

Yes I am struggling with this too. I wasn't at the seminar but from what I have read from those who have attended it appears that the sentiment is that crossing and fused branches are a precursor for the formation of weak codominant forks. Have I got this wrong? Probably!

[Gary Prentice]

You're not wrong.

 

The idea is that that crossing/fusing limbs limit movement/stresses that cause reaction wood which would, in time, strengthen the union. Much like the idea that cabling can act in the same way.

 

Remove crossing limbs in young trees(lower dynamic forces+faster growth of reaction wood), don't in older more mature trees where there's a probability of failure before strengthening can occur.

 

Duncan provided some categories of forks which were then additionally graded looking at the sustainability in light of the fused limbs above. I.e. Is the fusion complete and likely to be in place for the life of the tree. David's beech over the arch is a good example of a sustainable 'cable', so a weak Union becomes less of a liability.

[stevelucocq]

Yes I am struggling with this too. I wasn't at the seminar but from what I have read from those who have attended it appears that the sentiment is that crossing and fused branches are a precursor for the formation of weak codominant forks. Have I got this wrong? Probably!

 

sorry in a rush but you're not wrong.

 

we walked the site in Picton castle (new to Dr Salter) and examples demonstrating this were shown that were only identified in the morning. please note this is not a 100% rule like many things in nature but a statically high proportion demonstrate this relationship.

 

To me that restrictions between stems (graft/rubbing branches etc) leads to a weaker union makes sense. like weaning a tree from a stake to increase forces/movement to stimulate root growth, tree producing reactive wood to try to maintain optimum structural stability etc. it all fits together with me.