codominant stems

[boynature]

just wondering what everybody's opinion is on when is a co-dominant stem to large to be removed. I'm talking about trees with V-crotches that could someday split if they are not either braced or removed. 9,10 inches?

 

[Stumper]

In my professional opinion, such crotches actually exist. Some of them fail. Many do not. :angel:

When they are under 6" diameter I frequently advise removal of one side.(Actually this depends upon species-If it a peach or plum that is never going to be very large or tall then this is much less important than a maple that is heading fro 80feet and hanging over a house). When they are 9-10 inches It gets more dicey-remember-most included crotches DON'T fail-the potential for failure is simply statistically higher.

 

[Tom Dunlap]

Start a subordination pruning program. The sooner you can chagne the relationship between the two from branch to branch into a stem/branch the stronger the union will be. As long as they're codoms they will grow at the same rate and push each other apart. Getting one to become a stem and increase the growth rate will allow a branch collar to form instaed of a weaker codom union.

Reducing the foliage on one side by about 20-30% should get things going. You don't want to whack off the top of the subordinated leader. That's no better than topping. Make a reduction cut at the top and then do some thinning. When I;ve done this I try to clear away limbs on the sub limb that will compliment and encourage limbs on the dom limb to grow larger.

You're playing arbo sculptor here.

Adding a non-invasive cable is generally warranted to add some support to the weak union.

 

[treeseer]

Righto Tommylop!

boy, post a picture and we'll talk more. please don't overdo the concern--at the ginter gardens in richmond va, the staff went absolutely nuts, removing half of every tight-angled fork. The butchery was awful to see. better to underreact, and reduce rather than remove.

 

[John Paul Sanborn]

This is one of the times when Wolki would rant about dogma. Tight crotch, cut it out...

I have seen many stable large trees (many many silver maples) that have no problem surviving as included co-dominants. Subordination of one stem is allways a good first step, cabling may be needed, but this depends on how the tree moves near the union.

As Mattheck says, trees talk to us by how they add on wood. if there is a lot of asymetrical growth in that area, then adding something may be needed. If the moment of bens is farther up stem, then the tree has grown to accomodate the structure.

Then there is the study that Gilman did that shows that if the V crotch has no visisble seam to it then it is nearly as sound as a U crotch.

Cabling usually should be done from mutiple factors, if it's just one then other methods can reduce failur risks.

 

[Lumberjack]

...most included crotches DON'T fail-the potential for failure is simply statistically higher.

Can you explain that for me Justin?

If the tree is reaching maturity I would think that reducing the sub side would be poorly suited as the tree is slowing its growth greatly. Cabling is an option, I like cobra.

If the tree is young then subordinating is a great option, drop crotch reductoin and thinning.

 

[Stumper]

Carl, I'll try-I kind of thought the statement was clear.Many trees form "bad" crotches. Included crotches are "bad" crotches because they are more prone to fail. Being more prone to failure does NOT mean that failure is inevitable. In fact most trees with tight/included crotches stand up and hold together for their entire life. What we notice however is that trees with codominant leaders and included crotches are the majority of the trees we are cleaning up after a storm. An examination of the wood and growth of such crotches makes it apparrent why they are weaker and more prone to fail. Because codoms with included crotches are statistically more likely to fail we 1. try to avoid planting such trees. 2. remove one leader when they are young. 3. subordinate one leader while still a juvenile tree. 4. cable mature trees . These treatments are advisable to mitigate the increased likelyhood of failure. What we sometimes forget is that "more likely to fail" and "most likely to fail" don't necessarily mean "likely to fail". Most of them stay standing without our help.

-I actually cabled a codominant Mulberry today. -I'm not against it I just like for us to think about what we do and why. :angel:

 

[Fireaxman]

Where can I learn more about "Cabling"?

A lot of very nice trees were topped out by Katrina, often leaving several very healthy branches below the break. I am guessing those branches will now compete for dominance, possibly leaving us with some pretty extreme examples of co-dominant stems.

I know of at least one tree that was topped out in an earlier storm that is nicely symetrical and not at all unattractive (in fact the multiple stems provide a nice shade, highly prized in South Louisiana in the summer, I will try to attache a picture). So, my effort thus far, in low risk situations, has been to remove the broken top down to the first healthy limb and see what happens. Has anybody got a better idea? Would it be a good idea to "Cable" two or more healthy branches at the top to add strength?

Just hate to remove a tree that might stand a chance of a symetrical recovery at no risk to house or heavily trafficked areas. I have little experience or education in this, any advice would be appreciated.

 

[Tom Dunlap]

The first place to start is to read a copy of the best practices for cabling. The ISA has the pamphlet for sale.

There is information on the web but, like all web info, some is bad.

Cabling and bracing has been talked about in depth on AS and the other arborist forums. If you look at this like you're taking a night class, the research won't seem like a daunting task.

http://webboard.isa-arbor.com:8080/~ISA/search

http://tinyurl.com/7uj2b

http://tinyurl.com/bwk9t

 

[Gopher]

Talk to Guy...

Another resource would be (regarding creative pruning due to storm breakage) to contact Guy Meilleur. He has written some good articles and has much practical experience in this area.

I agree with you Tom; this is my approach when a tree is younger and of course. looking at species, location, etc.

I have a bitternut hickory at home that I meticulously pruned three years ago, and now it has a codominant lead at about 20 feet. I am not going to touch the tree again. It has lots of space, and I'm going to let the lower branches touch the ground. If it breaks, I am going to leave the limb on it if still in the tree (if I think it won't be a safety issue.) Right now the tree is about 30 feet tall, and I have another larger hickory tree that I have removed deadwood (the kids swing is in it) and prune about every other year.

Hopefully my wife will allow me to leave the tree go as my own experiment. I'll try and remember to post pictures of both trees soon, and we can follow the progress of both.

Happy Thanksgiving to all.

 

[treeseer]

yeah dave post a winter picture so we can see the architecture. you are right; hickories do not split codoms like ash etc.

fireax that is a beautiful tree and you are right it is a great candidate for cabling. The BMP's cost $5.

i met a lot of people at the urban forestry conferece from LA and mS. I asked what they advise on trees with >50% crown loss, and if heading cuts are ok. Got the standard answer; always go back to the next big lateral.

i asked the same question to 163 arborists at tci; 160 said yes heading cuts can be a good way to save damaged trees. those states need arborists now a lot worse than they need treecutters. fireax pm me if you want more info.

 

[Fireaxman]

Thanks, Tom, I found the ISA pamphlet on the web with no problem. I had tried a search here on Arboristsite for "Cabling" and I was spending a lot of time looking through places where it was mentioned but where there were few details and gudelines. I'm not scared of research, but time is precious, and my dial up is slow. The ISA pamphlet looks like just what I need - also saw a lot of other good publications that I would like to have.

Treeseer - yep, thanks, I want more info. So many trees went through roofs down here that everybody seems to want to cut cut them all down. I'm thinking maybe the trees pushed a lot of the wind up high, over the tops of the houses, possibly saving many houses from worse damage. Where I spent the storm (surrounded by tall pines) we had probably 150 mph gusts over the tops of the trees, but the house I was in saw nothing more than (I am guessing) 25 mph. No broken windows, not even a shingle blown off the roof. Fortunately the trees that fell did not hit the house.

In Slidell, Eden Isle, Chalmette - places that had no trees - there are far more houses destroyed all the way to the slab or pilings. Of course, those places were also closer to the Southeast quadrant of the storm.

Anyway, after the "Removal and Cleanup" phase is over, I'm looking forward to something more constructive. Saving the remaining trees.

 

[TheTreeSpyder]

Very good recommendations. Even if the tree doesn't collar the subordinate branch, and needs to be removed, it will be smaller wound. Keeping the low weight, gives wider trunk too; wide and low giving stability. All green saved, provides siphon through transpiration that keeps roots drinking up water and nutrients; also keeps tree machinery running freely at full steam.

CoDoms, make the tree oit itself against itself, instead of the house standing undivided. In codom the most leveraged angle of support is taken by the other half in branchings or as 2 separate tree units growing together. Codom also takes the shape from round, or sphere that is long on loaded axis, and makes a non-round; easily leveraged shape, that carries it's weight usually on the worst axis of support.

One of Wulke's points was that we watch out for horizontal codoms as the most leveraged and failure prone. But he witnessed that vertical codoms, didn't get exercised cuz of balanced vertical structure, then became easily hyper loaded in a few degrees and failed. For, the most leveraged is at horizontal. But the most increase in leveraged beyond the conditions you were groan at, is near vertical...

FireAxMan; just like in any battlefield littered with dead and injured; i think re-search is the best that can be gained; get out the camera! Show why the failures happened, and which ones would fail anyway in time. Only now all present themselves for group re-view like never before; the perfect classroom!

Included Bark Archive from Fl. Hurricanes of '04

 

[Fireaxman]

Treespyder - I can get a pretty interesting picture of what I think was a dramatic failure of a co-dominate stem tomorrow if someone has not cleaned it up yet; but more of a mystery to me are the co-dominates that did not fail. They seem to be witnesses for John Paul Sanborn.

Of course, a lot has to be attributed to the caprice of the storm- downbursts and tornadoes did a lot of the damage in a seemingly random pattern - and I think the oak in my post of 11/19 was protected by its proximity to a lot of much taller pines (since by luck or grace it did not suffer a direct hit from a blown down pine). But it still surprises me that most of those crotches held up, especially a "Raccoon Nest" in the center of the tree where the original top broke out. It actually held water, and I would have thought it should have rotted out long ago.

Therefor my interest - when (and how) to cable and when should I just not worry about it. I'll just have to post some picts before I start drilling any holes and see what you guys can tell me.

Thanks John Paul when you told me something to watch for in quoting Gilman "Then there is the study that Gilman did that shows that if the V crotch has no visible seam to it then it is nearly as sound as a U crotch" (post of 11/16). Even then, isn't it interesting that the crotch in front survived with such a deep seam when the tree took enough wind to lose several seemingly healthy laterals? (Arrow) That crotch in particular is the one I would like to cable, especially since it threatens the power line.

 

[Fireaxman]

Codom Blown Off by Katrina

Promised you a picture. Loblolly, about 30" dbh. Failure is about 30 feet up the stem.

I sure have had to be very careful with the spelling on this post. An extra "n" keeps trying to sneak into my abbreviations.

Anyway, the codominant stem was blown off by Katrina.

 

[treeseer]

Pine codom failures are almost always fatal; the wood is so straight-grained, the wound is huge. I lost a 23" er taht was codom 50' up; the rest of the tree died soon after. Tuliptree and ash and red oaks are also bad for that; maples elms and white oaks much less so.

 

[Old Monkey]

Tom or Treeseer, do you guys have any good picts or sketches of how to subordinate a codominant stem? I think I get what you are talking about but illustrations are helpful.

 

[treeseer]

Yes, Gilman's is the best. what you want is at the bottom of the menu: Powerpoints, Pruning, Structural Pruning has a lot of images on proper subordination. Should be clear enough to satisfy any skeptic.

The section on Reduction has an unfortunate drawing of horizontal wounds made by tip-pruning a storm-damaged tree. Wounds should always be as vertical as possible. Also he looks for a "clean" trunk up to 20', which in some sites is way excessive. But these are nits picked off of what should be industry standard.

Dan yes I would not want to climb that split pine if there was another way to deal with it.
Fireaxman, Gilman's ppts are freeware; the pruning one should be shown throughout Katrina country.

 

[John Paul Sanborn]

http://www.ext.nodak.edu/extpubs/plantsci/trees/f1055w.htm

The above is a link to a very good manual on farmstead windbreaks from NDSU.

A well planed windbreak ramps the wind up and over structures, one of the problems we have in urban/suburban areas is that we let trees grow tall, or clear out tall tree areas, but do not have any of the low growing trees on the edges to bring the wind up over the lrge trees.

Of course this is just one of many factors involved but an important one.

 

[Redbull]

This link could be helpful in some co-dom situations http://www.treelink.org/joa/2000/may/05_BRACE_RODS_FOR_CODOMINANT_STEMS_smiley.pdf

I am curious though, when does a co-dominant stem justify using a bracing rod vs. just a cable, or both?