Ekka
Addicted to ArboristSite
Lordy, another genius .... Shigo would turn in his grave. :notrolls2:
Sure, the a healthy tree has had a large limb cut off, and closes over. The discussion is on trees that have lost a significant portion of their canopy.
Our position is that "reparation" trimming should be managed gradually, you say cut everything to the collar, even if you are cutting "half" the tree away.
To paraphrase the eminent Dr. (call me Al) Shigo, the debate is about dosage and time.
I say apply a gradual, and thoughtful, management program.
You say lop'em all off now and be done with it.
You say we are reverting to old bad practices, I say the "new" ideology has now become dogmatic. You are a great example, with your bombastic pillorying of those who take a stance counter to the party line.
There doesn't appear to be much difference in the regrowth from a nodal cut to an inter-nodal cut IMHO.
Both cuts push out a lot more than 1 new shoot from 1 bud. Both cuts require returning to thin out the suckers and manage a strong one or two.
When I prune roses to a node I get one new stem growing, I can even determine the direction that stems grow by cutting to say an outward facing bud ... that's how you prune roses and things like hibiscus. I feel that the inclusion of the terminology "nodes" as a target point was introduced to satisfy the whims of a broad spectrum of horticultural people. Sure trees have nodes on pencil sized stems in the nursery however in large established trees where we are talking about cutting 4" dia+ branches the practice has been skewed to fubar to satisfy some academic reasoning..... not saying that nodes do not exist just that cutting to them evokes about the same problems and management as a straight forward topping!
Those trees in your pictures Guy look like round over topping jobs, those re-established canopies you see on the ice work trees same, argue what you like but I'm not the only skeptic. We are yet to be presented with a good sample of disected nodal cuts and topping cuts 3 years and 5 years afterwards, disected on both axis to see the difference.
In the recent storms here many eucs lost their tops, those where all leaders etc were broken were removed. What are you going to do, have 50 epicormic shoots growing from every cut to manage on a grand scale of 1000's of park trees?
I can see the use of this for crown restoration on selected trees but on a grand scale you might want to bring in an orchard pruning machine and clean cut the trees en-mass, end result would be about the same.
The sprouts you both herald as the decay savers only feed the vascular cambium, so the heartwood remains as unprotected as before. Sprouts do accelerate sealing of the wound though, so stub ends will grow over faster with sprouts than without, but many times sprouts die within 3 years too and you'll be left with a huge advertising sign "yo bugs, mega banquet here".
Sprouts also occasionally emerge near target cuts, it's suggested by many experts to leave them as they once again speed up the sealing process, however they do need to be managed, I'll see if I can get some pictures.
I have the same difficulty, but with enough study we may be able to come up with a reasonable protocol.The difficulty for learning arborists like me comes in understanding why one calluses and another doesn't.
tHE 1/3 rule and the collar cut are starting-off places. Note that Shigo (who admitted he was still learning, and encouraged us to not rely on his findings but learn for ourselves) endorsed pruning to nodes, saying that every branch is different, and that rules are too strict for Mother Nature. He defined a node as a place where the terminal bud was set--much easier to see on other species than on eucs, so you in Oz obviously may find it harder to follow.I am drawn to the concept of removing as little of a tree as possible post trauma but TV and Ekka have both posted information which lines up with my meager botanical knowledge.
Those trees in your pictures Guy look like round over topping jobs, those re-established canopies you see on the ice work trees same, argue what you like but I'm not the only skeptic.
What would they look like if he had cut them back further? Probably a stump.
In the recent storms here many eucs lost their tops, those where all leaders etc were broken were removed. What are you going to do, have 50 epicormic shoots growing from every cut to manage on a grand scale of 1000's of park trees?
I can see the use of this for crown restoration on selected trees but on a grand scale you might want to bring in an orchard pruning machine and clean cut the trees en-mass, end result would be about the same.
7.3.5 Remedial (restorative) pruning (H)
This type of pruning shall only be carried out on trees which have lost their natural form and structure through storm damage, mechanical damage, vandalism, lopping, dieback or disease. This method is usually only used when all other approaches have failed and replacing the tree is difficult. The purpose of this pruning is to prolong the useful life expectancy of such trees and to reduce their hazard potential. This type of pruning removes damaged, diseased or lopped branches back to undamaged or healthy tissue. The final cut may not necessarily be at the branch collar. The aim is to induce the production of epicormic shoots from which a new crown is intended to be established. To achieve this, regrowth should be managed by reduction pruning or crown
thinning.
NOTES:
1 This type of pruning should be done in several stages in an attempt to induce stable and successful regrowth.
2 Consideration should be given to removing dangerous trees.
3 Remedial pruning may create hazards from weak branch attachment. Trees should be carefully monitored.