Reduction Pruning on Large Trees

On the other had when working on older juvenile maples, some structural pruning to remove several interior branches on the main stem may be needed to thin out a group of limbs that are growing too close to each other. These limbs that grow so close to each other can eventually put on enough girth to grow into each other in a way that girdles the top or the side of the crown above that group of lateral limbs.

 
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Reduction pruning an entire tree is much like retrenchment pruning. The goal isn’t exactly for aesthetics, but more so for triggering a desired response which could pull a tree out of decline by triggering a flush of growth in smaller overall volume.
It works great most of the time.
The tree in question has no need for this type of pruning as it still has plenty of vigor.
 
evo said:
Reduction pruning an entire tree is much like retrenchment pruning. The goal isn’t exactly for aesthetics, but more so for triggering a desired response which could pull a tree out of decline by triggering a flush of growth in smaller overall volume.
It works great most of the time.
The tree in question has no need for this type of pruning as it still has plenty of vigor.
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No, the goal of reduction pruning is to ‘reduce’ the size of the tree.
Clue is in the name.
 
We get alot of requests for this type of work here and like @ATH Said it's turns into high maintenance, but some people inherit the trees beyond a time where much of anything else isn't sufficient beyond removal for whatever their reasons are.. I say prune it , remind them they're turning it into a high maintenance mechanism and perform the work best possible based on circumstance, get paid. I manage maples, and other cultivars of course, my grandfather worked on since 1980s some even 70s. not all full reduction prunes, but some needed biannual or so. The are business builders as they keep coming back for more..
 
I've got a white pine in my front yard. Been in this house since 2002... at the time I moved in, it looked as if someone had hit it pretty hard some years before... They took enough off the main central leader than many of the uper leads began to compete for dominance which have kept the tree looking fairly compact and robust in shape, with thick deep green foliage. Kind of like a ginat christmans tree. I remember thinking that the tree looked as if it had been butchered or hit way harder than I thouht was good abck in 2002.


At the time, a buddy of mine went up in the bucket and shaped it up. I forget exactly what he did , but it was all tip work, nothing too much.

That tree has been bullet-proof ever since... A lot of the pines here are dying, they either get thinner and thinnner for a few years, or they just turn brown overnight... and they are extremely prone to ice and snow damage. That tree is so thick and full, and made it through the worst ice storm anyone around here can remember in 2014 only losing a handful of limbs when many other pines were completely trashed. I have really been amazed at how well the tree is doing and I think the heavy reduction pruing over 20 years ago, before I got here, has a lot of that has to do with it.

I keep meaning to give it another trim, but it looks so good, that it hasn't been a priority. Based on that tree and a number of Norway maples with long lanky crooked and cracked limbs that came through that same ice storm with no damage, I have developed a theory about reduction pruning.

When a early stage mature tree is tipped back with reduction cuts throughout the canopy, even lightly, that will permanently change the relative taper of the limbs, which is a fucntion of the diameter of the limb compared to its length. The added taper compared to length that it gets from this pruning will be very effective at reducing storm damage for the life of the tree..

YOU HEARD IT HERE FIRST...

and once again, it just makes sense, but no one ever thought it before...
 
Daniel

YOur comments on the white pine remind me of a white pine story.

WP is historically significant in the forests of Minnesota. From Mpls north through the center of the state the forests were mostly WP. Pretty big too.

I found an article about a biologist who studied the current and historical white pine forests in the US. He found the highest concentration of BIG trees in an area that was not at its southern range. That was a surprise to him. He expected to find them in the Maine to Minnesota range.

After a lot of study and looking for variables he came up with a hypothesis.

This range or line of big trees was at the 'snow and ice line'. The trees would periodically get snow and ice loads that would strip out individual branches or the whole forest. The trees wouldn't die, they'd regrow new branches on old wood.

Even though the northern range of WP would get more snow/less ice it wouldn't stick to the trees so the trees grew thinner and taller.

By doing the thinning and crown reduction that we;'re doing is similar to the ice/wet snow damage or even bonsai. We're artificially doing what nature did all along.

I've never liked the line I hear tossed around by arborists about how trees grow optimally. That;s true for some trees. The solo or open area trees can usually do just fine with little pruning. Around here it would be the savanna and prairie trees.

Trees taken out of the thick forest and open grown in cities grow different than their cousins in the woods. They then need more active care to grow them into structures with good architecture. Good unions. Shorten over-reaching limbs. Concentrate growth in shrunken canopies.

Most arborists would agree that walks in the natural forested areas or post storms is where they have learned how to do structural pruning. Like those WPs there is a benefit to doing some reductions for survival.
 
Great discussion. I am doing a lot of pruning on an Island where high winds are a constant feature. This has me looking a lot at the far-reaching long limbs. I am reducing them to limit bending and torsion.

Checking out some trees that Daniel has been pruning with these reduction cuts shifted my perceptions around how to help healthy form in trees. It takes effort and time to put a branch out there, and plenty of dormant nodes are ready to fill in a new space (after reduction). Pulled back away from houses, or out of the wind, giving that branch time to strengthen it's attachment, rather than complete removal.

I have a few requests just to "bring it in", on a Zelkova in particular, they want an all around reduction. I think I can meet their request without killing the tree's dignity or my integrity. They planted the tree themselves and expressed interest in ongoing maintenance. We are here interacting with life on Earth.

I had a funny moment with a client who wanted me to open up some ocean view, I was in an old mature Pear tree. I kept telling him I could not bring it down the entire amount he wanted. Perhaps over a few years we could encourage a lower top-height. He asked again and again.. I refused. Later on we were laughing.. he knew he was asking for bad practice (has some horticultural background) and told me I passed the test by standing up to him.

I am undergoing a shift from classic Shigo full-branch removal proper-pruning cuts as preferred, to more use of smaller reductions and even heading cuts. Keeping wounds away from the trunk and allowing the new sprouts to be in open air rather than on the trunk.
 
dspacio said:
I am undergoing a shift from classic Shigo full-branch removal proper-pruning cuts as preferred, to more use of smaller reductions and even heading cuts. Keeping wounds away from the trunk and allowing the new sprouts to be in open air rather than on the trunk.
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Glad to hear it.. and that's a lot easier to do with the aid of a ucket truck to reach those long over-extended laterals
Tom Dunlap said:
Daniel

YOur comments on the white pine remind me of a white pine story.

WP is historically significant in the forests of Minnesota. From Mpls north through the center of the state the forests were mostly WP. Pretty big too.

I found an article about a biologist who studied the current and historical white pine forests in the US. He found the highest concentration of BIG trees in an area that was not at its southern range. That was a surprise to him. He expected to find them in the Maine to Minnesota range.

After a lot of study and looking for variables he came up with a hypothesis.

This range or line of big trees was at the 'snow and ice line'. The trees would periodically get snow and ice loads that would strip out individual branches or the whole forest. The trees wouldn't die, they'd regrow new branches on old wood.

Even though the northern range of WP would get more snow/less ice it wouldn't stick to the trees so the trees grew thinner and taller.

By doing the thinning and crown reduction that we;'re doing is similar to the ice/wet snow damage or even bonsai. We're artificially doing what nature did all along.

I've never liked the line I hear tossed around by arborists about how trees grow optimally. That;s true for some trees. The solo or open area trees can usually do just fine with little pruning. Around here it would be the savanna and prairie trees.

Trees taken out of the thick forest and open grown in cities grow different than their cousins in the woods. They then need more active care to grow them into structures with good architecture. Good unions. Shorten over-reaching limbs. Concentrate growth in shrunken canopies.

Most arborists would agree that walks in the natural forested areas or post storms is where they have learned how to do structural pruning. Like those WPs there is a benefit to doing some reductions for survival.
Click to expand...
agreed 100 %.

I've been noticing some ash trees that appear to be doing thier own retrenchment pruning. The hyposthesis is that not enouhg insecticide was applied so the tree couldn;t get it all the way to the branch tips, leaving the bugs to kill the tips and the tree to respond with a thick full lush lower canopy....
 
dspacio said:
I am undergoing a shift from classic Shigo full-branch removal proper-pruning cuts as preferred, to more use of smaller reductions and even heading cuts. Keeping wounds away from the trunk and allowing the new sprouts to be in open air rather than on the trunk.
Click to expand...


I don't know what you mean by '..classic Shigo....'

When I took his five day class, in the mid 80s I think, he gave us the idea of reducing limbs. Take off enough foliage to allow the branch to sustain, not die. Time goes by and the trunk or main branch increases in diameter. Our reduced limb stays small. This triggers the chemicals in the tree to wall off the pruned limb. Possibly remove later or not.
 
Tom Dunlap said:
I don't know what you mean by '..classic Shigo....'

When I took his five day class in the mid 80s I think he gave us the idea of reducing limbs. Take off enough foliage to allow the branch to sustain, not die. Time goes by and the trunk or main branch increases in diameter. Our reduced limb stays small. This triggers the chemicals in the tree to wall off the pruned limb. Possibly remove later or not.
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In Modern Arboriculture there is a lot of focus on the proper pruning cut made at the trunk of the tree. All the talk about cutting beyond the branch collar etc.
The colloquial way I learned did not emphasize reduction cuts. Usually if a limb was troublesome that whole thing was going to disappear, or maybe back to a hearty lateral. I never saw well-done intentional heading cuts.
I have seen a lot more nuance over the last ten years of watching tree work.
 
This could devolve into word definition but that's not my intent. These days we've got better language to use.

When I make a cut I look at the removed part as the branch and the living part on the tree as the trunk. My cutting takes into account diameter ratios etc. as well as the reason for doing any cutting in the first place.
 
@Daniel your video talking about how reducing a limb by 15% can increase its strength by 50% has had me thinking about it for a few weeks now. It makes sense. I learned full-tree reduction in my first couple years in the trade, from an Englishman who was very good at it. So many of these trees in the city are hardier than we give them credit for. These blanket rules that are taught to new tree guys are just way too simplistic. Such is the way that most things are taught I suppose.
 
Daniel said:
I wouldn't call that retrenchment... taking the entire top third of the tree off to 12"+ stubs... that's toppiong
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Twas dead, cutting to get regrowth. Check out commercial citrus retrenchment, looks like topping and heading cuts everywhere until the leaves explode
 
Muggs said:
...reducing a limb by 15% can increase its strength by 50%...
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This is not meant as a criticism...stay with me.

Pete Donzelli made a point when talking about knots in ropes. In rough numbers a knot in a rope will reduce its breaking strength by 50% or some such. But, that's only when its loaded with the knot. The rope is back to full breaking stength after removing the knot. He talked about the knot reducing the 'efficiency' of the rope instead.

Same here. The uncut branch will need X load to break. Reducing the lever arm will reduce the breaking load some theoretical amount. The branch has changed but its just as strong. What;s been done is to change the breaking load not the strength.

Something more to mull over.
 
Guy Meilleur used to post years ago. Maybe worth some searching.

Tom I think you typoed an oops. Shorter lever same thickness can handle higher load at tip, tip load usually representing general wind/snow load. Maybe 50% eventually shows up by taper and aspect ratio via growth pattern.

edit - on close re-read of your post it could just be semantics finery:)
 
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