Wind resistant trimming

[evo]

The thing with this job is I’m not as familiar with the needle bearers. A deciduous would be an easier reduction in my mind. How would one reduce an excurrent tree?! The topping is sounding like the least worst way to go. It can be cut to where they cannot hit the home and maintain it as the growth dictates.

It kinda is topping.. but the distinction between the two is avoiding cutting into the heartwood, and cutting it back to a node.. A node in a conifer is a whorl, as long as the cut is made small and the regrowth is trained its do-able (I DON'T unless there is no other option).. The tree still responds the same LOOOONG heavy limb growth below the cut, and multiple tops will form. Some species like western red cedar, will reitterate from limb tips too (another management can of worms). HOWEVER crown reduction by shortening the terminal is very good with stability in the wind, but IMO it should be sold only with a repeat visits every 3-4 years (my area).

 

[evo]

A lot of this is species dependent.

Once wind gets inside a Douglas for example it’s one branch failure after another.

Not exactly.

 

[evo]

Matias, I hear you on the maintenance. I’ll lay it all out for the folks and let them make an educated decision.

Sean, so where do you clip? The very ends of the limbs?

I almost always aim to make small cuts, the secondarys tend to spiral in the smaller wood, I will leave a small stub below a secondary that assumes the direction of natural growth. Sometimes I will snip any others growing out at 45-90 degree angles.

 

[evo]

Don't forget and I hope @Matt Follett chimes in.. THINNING secondary laterals is effective to reduce whip and more pleasing to the eye in a conifer, but this thinning is more like 10-20% of the green of the branch tips inward to the stem, not the other way as is common. I don't view limb removal as thinning on a conifer.. It's simply limb removal.

EDIT: One question I have that has gone unanswered is; crown reduction is very effective at reducing likely hood of failure of the part. Now if everything is reduced the tree becomes stiffer. Does this make the wind hit the tree more like a wall or building? Thus potentially making it more prone to soil failure? remember here in the PNW, wind typically comes before/durning/after a heavy rain in the already wet season.

 

[SeanRuel]

I have hard reduced Picea rubens,, but don't take tops bigger than about 3 inches when reducing. Best case scenario you can take it to a whorl that has some strong upward growth to become the next top

Pretty much what Evo said about pruning to reduce length but maintain outwards growth direction

 

[Matias]

Don't forget and I hope @Matt Follett chimes in.. THINNING secondary laterals is effective to reduce whip and more pleasing to the eye in a conifer, but this thinning is more like 10-20% of the green of the branch tips inward to the stem, not the other way as is common. I don't view limb removal as thinning on a conifer.. It's simply limb removal.

EDIT: One question I have that has gone unanswered is; crown reduction is very effective at reducing likely hood of failure of the part. Now if everything is reduced the tree becomes stiffer. Does this make the wind hit the tree more like a wall or building? Thus potentially making it more prone to soil failure? remember here in the PNW, wind typically comes before/durning/after a heavy rain in the already wet season.

That does seem to be what's indicated by the research linked earlier in the thread. It's in line with some failures I have seen in my area wherein the guy who was doing the cutting gets called out for not cutting enough, but it seems it may be the other way around. I feel like I have so much more to learn than I ever imagined, and I have been studying for many years.

 

[SeanRuel]

Most failures here are also wind events following soaking rain. Not a scientific study but for spruce on ledge, it seems like reduced trees survive about 50-75% more than non pruned trees. A boat under bare spars can still capsize, but less likely than one flying all its canvas( could be a bullshit analogy but that's my thinking anyways)

I don't think unpruned trees have so much more flex than reduced ones for it to be a huge factor

 

[southsoundtree]

What are/ is the acceptable method of trimming to thin out a conifer species for wind resistance? A neighbor said the has a line of spruce trees that could kill the house and other targets. A terrible storm recently broke a 40’ top out of one of them and now he wants to do some type of prevention. I’d rather not take the top off and then re trim it every 5-10 yrs.

Did it break through a single trunk, split between multiple tops with inclusion, break one of two tops without inclusion, or...? Was there a pre-existing defect?

 

[Treeaddict]

Did it break through a single trunk, split between multiple tops with inclusion, break one of two tops without inclusion, or...? Was there a pre-existing defect?

I’m not sure as I haven’t put eyes in his situation yet. He’s only told me about what happened and his thoughts going forward. Im trying to arm myself with as much knowledge as possible before I see his yard. Those are very good points regarding sound wood. We’ll have to see what the others structures are like.

 

[Redtree]

Focus on preventing twisting as much as possible. That is where wood is weakest.

A few years ago, I was at a conference where Frank Rinn was presenting. His suggestion was that "thinning" doesn't reduce wind resistance - it can actually increase it. Instead of the tree taking a shot of wind on one side while the rest is protected, when a tree is thinned, there is now drag on every branch meaning the load on the trunk is increased.

Height reduction is the most significant way to reduce wind load on a tree. That is unfortunate from a tree management standpoint...but that is physics.

I like the height reduction point best. Even today when I lifted my pole pruner above the max canopy height (70’). I could feel an increase in wind speed. So there is a compounding of leverage combined with wind speed as you ascend. The higher you get, the higher the wind speed, particularly approaching and passing the canopy ceiling. I find that it is rewarding to deal with the challenges you reflect with the accurate comment: “unfortunate from a tree management standpoint”. It’s a matter of accepting vigorous reaction growth that is natural but is seen as unnatural. Some responses will be uglier than others without being any worse. And later you can manage and selectively reduce response growth. It’s not always an aesthetic competition but you can improve or retain good aesthetics usually. Often you give up grace for handsomeness. An increase in masculinity but It’s not toxic or a sex change.

Your second best point is preventing twisting, which is accomplished not by thinning but by reducing.

Third best point is the “suggestion” of Frank Rinn’s. Depending on the “thinning” you do, wind load may stay the same, or reduce but an increase I suspect unlikely in a large tree (didn’t Rinn study on small trees?). I remember there were skeptics. Anyway I think the recent notion to remove “thinning” as a term is a mistake, even if it should take back seat to “reduction”


Sent from my iPhone using Tapatalk

 

[Redtree]

Here is an article with some good info:

Tree Crown Reduction Decreases Mass Damping of Wind-Induced Oscillations and Wind Energy Dissipation

Article by David S. Restrepo Inspired by Tree Myth #98 "Pruning decreases wind load on trees", from Christophe Drénou's latest book: Beyond Tree Myths L’arbre.

www.linkedin.com

I disagree and my observations of trees reduced outweigh my observations of this article. Just the opening statement alone, “Tree myth: arborists say pruning reduces wind load”. First define “pruning” which is otherwise a broad and useless statement given no context of dosage or cut diameters. At some point in the severity of the reduction dosage, you certainly get a decrease in wind load. And second, when you reduce a 60 foot sphere to be a 40 foot sphere, while retaining but reducing every branch, you still get damping effects. And you have a significantly smaller shape for the wind to go around. I suspect the concepts in this article don’t fit into practice because they don’t apply to large trees. Then again I doubt they apply to medium trees either. Increasing taper (countering slenderness) can only improve resilience is my suspicion. And very effective in practice.
I’ve observed reduced trees, beside the trees that aren’t, to sway less distance with a shorter frequency. The less distance part seems telling to me. And the decrease in storm mess, confirmed by golf course managers and clients who report little to no mess during storms following reduction. The May 21 derecho storm in Canada (winds 60-160 mph) gave observation to conclude from, for me it’s no longer suspicion. Reduction, especially thoroughly, gently and repeatedly applied, improves taper and storm resilience. The dose and dosage just both need to be accurate, not precise. Meaning roughly enough is taken off, but not too much, and it’s done frequently enough.


Sent from my iPhone using Tapatalk

 

[Redtree]

Reduce all branches or as many as practical by 20% of their greenery, here in Maine it's very doable with an pole clip BTW 8-16 feet. The tops don't have much sail area. I usually climb up to 4 inch trunk, do some clipping above, and then work down.

Try to mimic/ maintain the existing canopy shape, just making it smaller

Best thing I’ve heard in a while. For cases where vulnerability seems high I would add a possible variance: reduce branches of upper third by 30-40 percent and middle third by 25 percent and bottom third by 0-10 percent. This retains foliage to shade feet and increases the dose where it’s needed without increasing the overall dose.
Funny this is precisely where shaping, and following the original shape is a perfect cross of shaping and structural gain. Other pruning can borrow this concept. By shaping a commonly square Norway Maple to be round, you are actually making it closer to conical.


Sent from my iPhone using Tapatalk

 

[ATH]

.....

Third best point is the “suggestion” of Frank Rinn’s. Depending on the “thinning” you do, wind load may stay the same, or reduce but an increase I suspect unlikely in a large tree (didn’t Rinn study on small trees?). I remember there were skeptics. Anyway I think the recent notion to remove “thinning” as a term is a mistake, even if it should take back seat to “reduction”

Regardless of Rinn's suggestions, I think it was very appropriate to take the term "thinning" out of the standards. Anything useful/helpful can be accomplished with a more specific term. Crown cleaning (a little less nebulous, but still leaves a lot of room for interpretation). Removing dead. Remove crossing and mal-formed branches. Improve air flow. Etc... "Thinning" is too nebulous.

In my observations it also leads to lions-tailing because people think they should take all of the branches out of the middle of the tree and leave everything on the ends when they "thin" a tree. I'm not suggesting that is what thinning actually is, just that too many people practice it that way, (I honestly, don't know exactly what "thinning" is...could be lots of things, but shouldn't be lions-tailing).

 

[Matias]

I disagree and my observations of trees reduced outweigh my observations of this article. Just the opening statement alone, “Tree myth: arborists say pruning reduces wind load”. First define “pruning” which is otherwise a broad and useless statement given no context of dosage or cut diameters. At some point in the severity of the reduction dosage, you certainly get a decrease in wind load. And second, when you reduce a 60 foot sphere to be a 40 foot sphere, while retaining but reducing every branch, you still get damping effects. And you have a significantly smaller shape for the wind to go around. I suspect the concepts in this article don’t fit into practice because they don’t apply to large trees. Then again I doubt they apply to medium trees either. Increasing taper (countering slenderness) can only improve resilience is my suspicion. And very effective in practice.
I’ve observed reduced trees, beside the trees that aren’t, to sway less distance with a shorter frequency. The less distance part seems telling to me. And the decrease in storm mess, confirmed by golf course managers and clients who report little to no mess during storms following reduction. The May 21 derecho storm in Canada (winds 60-160 mph) gave observation to conclude from, for me it’s no longer suspicion. Reduction, especially thoroughly, gently and repeatedly applied, improves taper and storm resilience. The dose and dosage just both need to be accurate, not precise. Meaning roughly enough is taken off, but not too much, and it’s done frequently enough.


Sent from my iPhone using Tapatalk

I have seen it go both ways, but what you're saying has been the case for me almost every time. Those exceptions are outliers, and there are other factors tors that contributed to their failure

 

[Stumpsprouts]

I’m wondering about cases when a conifer has a heavy lean- I have performed and sold work where we have gone and removed branches in the direction of the lean to reduce the leveraging weight. Maybe that was pointless.

Removing the top has never felt like a good solution but this discussion is certainly making me wonder if there were some times it is warranted and the only real way to reduce the risks associated.

 

[ATH]

What is going to cause the tree to fail? Wind? Reducing weight on the heavy side may not change much. Or, are the roots going to let go in saturated soil? If so then I think weight reduction could play a huge role.

Taking the top out of a conifer I think delays or transfers the risk. I don't think saying it permanently reduces the risk is 100% accurate.

 

[DSMc]

A transfer of risk is a very good way to look at risk reducing efforts. What is important is to understand the consequences of your choices.

Deeming a corrective procedure inappropriate because it is not a permanent 'fix' is just not reasonable, IMHO. Even a good roof will eventually need to be repaired.

 

[Matias]

A transfer of risk is a very good way to look at risk reducing efforts. What is important is to understand the consequences of your choices.

Deeming a corrective procedure inappropriate because it is not a permanent 'fix' is just not reasonable, IMHO. Even a good roof will eventually need to be repaired.

I think this covers the whole concept nicely. Are there ideals to strive for? Of course, but they're not always feasible for one reason or another. I mean, they make equipment of all sizes, so with enough time, everything is reachable, 100% of the time. Is it always worth it to get a 190' lift and a giant crane? Maybe not. If the client has unlimited resources to throw at a problem, and they want to go a specific route, I just have them sign an acknowledgement that I advised otherwise and am simply executing the HO wishes on their private property. If the next big wind cause a failure, they only get to cry and not sue, but such a hypothetical client probably wouldn't cry anyway; just move on and pay for repairs.

 

[evo]

I’m wondering about cases when a conifer has a heavy lean- I have performed and sold work where we have gone and removed branches in the direction of the lean to reduce the leveraging weight. Maybe that was pointless.

Removing the top has never felt like a good solution but this discussion is certainly making me wonder if there were some times it is warranted and the only real way to reduce the risks associated.

I came to the revelation a few years back that the answer depends on the need, and the market. Around here, I am VERY reluctant to reduce a conifer's lead. It can be VERY effective, but it WILL require a number of prunings if not pruning for the life of the plant. I'd like to think in the city (seattle) trees are more likely to get regular care than here...

To add to the 'thinning' conversation. Thinning CAN have nearly the same effect as reduction pruning. I use the dorky foam antenna ball analogy. lower the ball (COG) down the antenna it settles down very quickly after a good flick. Thin the tips not from the inside out. In fact a combination in a conifer is critical. Reduce the limbs that stick out the furthest, and thin the tips. keep the natural form of the limb over a bunch of 45-90 degree regrowth angles. Same with reducing the leader "Top and tip". Reduce the remaining laterals pretty heavy, it keeps the regeneration of new leaders as close as possible to the the stem and makes for future prunings much easier

 

[Redtree]

This blue spruce blew over by 20 degrees in the Friday May the 4th storm of I think 2018. I just remember “may the 4th be with you”. The tree leaned toward the camera point and the root plate was slightly tipped but didn’t fall. Anyway we cut the first branch and I halted to speak with the owner. I suggested a temporary support line into the maple behind (barely visible on the right in the after pic). This was the second reduction and the support line (section of old rope) was reset to be loose. No need to cut the top off by much. Just a reduction of all upper foliage by half. And with being cut twice, a few feet shorter, a vulnerability is reduced. The rope is likely unnecessary at this point but may as well stay in, with 6” slack for a few more years. The before pic reveals a bit of a funny reaction but nothing causing a problem. The tree is essential privacy patio to patio.


Sent from my iPhone using Tapatalk