What is the latest on pruning large conifers?

M

MeganS

I recently pruned a large doug fir for end-weight reduction on the lower third to two-thirds--the job specifications were to open up the view and sculpt the lower branches a bit. Because the top half of the tree was not blocking any view, I left it alone other than cleaning dead and badly damaged branches out. I was discussing this tree with another tree service yesterday, and he suggested that the tree looked a little top-heavy, and the biggest mistake people make when pruning is not thinning enough at the very top.

The catch here, though, is that this was not a wind-sail reduction; I don't do those, at least not through my own company, because I feel they are usually too drastic and I am scared to do it incorrectly, and I have seen trees fail from being over-thinned. I have gotten to the point where I don't like doing them for other companies either, because I am never given enough time to really get out to the ends and do weight reduction, they usually just want to see a big pile of branches at the bottom of the tree within a half hour. So I was only addressing the branches obscuring the view, and hazard branches. Should I have continued the end weight reduction up the entire tree? Is this advice more wind-thinning woo, or is it legitimately important to take more off the upper third of the tree than you take from the rest of it? I should note that it was topped many years ago...
 
Sounds to me like you did a great job doing what was specified on the work order and sold to the customer. Unfortunately what is arborculturlly correct and what the customer wants / is paying for is a fine line ( sometimes very grey area ). Take some pics.
 
First of all, Welcome MeganS to the buzz. Sorry I can't help you out with your question, I am at the opposite end of the country and haven't seen/touched a Doug Fir in a decade other than a Christmas tree. But I am sure there are guys out there that can help out.
 
In my experience, truly excurrent conifers need very little in the way of weight reduction or thinning to mitigate risk of failure. They are well evolved structures. The fact that yours was topped changes things... I would have tried to sell weight reduction of poorly attached leaders, not necessarily long ends. The tree probably looks top heavy due to having more than one leader after topping, thus being 'crowded.' I'm only speculating, though.

-Tom
 
Around here doug firs are pretty sturdy trees. Wind sailing is still open to debate if it works or not. I would look into mass dampening, why, and how it works. We don't wind sail, however there are companies that do in the area. Generally if you are seeking a more wind firm tree end weight reduction will "firm" up the tree in sustained winds, and lessen the chance of limb breakage. However if your concerned about the tree up rooting, or breaking at the lower stem do you want to make the structure more rigid, or to keep the mass dampening effect?

Traditional wind sailing if it even works may make the limbs more susceptible to breakage. I've heard that there have been studies done that to effectively remove enough sail you have to take up to 80% of the green (not good!). I would think that "crown reduction" end weight is the better option. This is done with out topping of course, or messing with the leader at all, just slimming the profile.

If the tree was topped, well that just depends on the tree/site.

I feel that with Doug firs a general crown cleaning is all the thinning they need, besides aesthetic concerns.
 
If the Dougfir had been topped, you're right in suspecting that more should have been taken out of the top. Nick Dankers did an AWESOME presentation at ISA last month, showing some great work with Dougfirs getting restructured high and low.
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He uses a reduction style very similar to the Morphogenesis guy in the UK. evo is onto it; ""crown reduction" end weight is the better option. This is done with out topping of course, or messing with the leader at all, just slimming the profile.", though sometimes the leader has to be messed with, a little.
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I'd love to see some info From Nick (Niko?) Dankers on that. Last I knew, he was working for long time PNW Consulting Arborist Scott Baker, who is here sometimes, or maybe more, lurking.

MeganS, where are you located?

I've worked on three large DF lately, each without their original top, so very long limbs. two'topped', one storm broken, or topped with a single leader. I inspected the co-dominant union, and did EWR, as 40'+ limbs were snapping along the neutral plane.

Most Doug-firs, if they are original-leaders, don't seem to need much more than canopy cleaning, unless they are remnant trees, newly exposed to more wind loading.
 
Hahahahaa I just bought a dump truck from that Nicholas Dankers fella. I will get ahold of him and get his thoughts on it. I am on the Kitsap Peninsula, west side of the Puget sound from Seattle WA. I haven't figured out how to post pictures on here, but I put some up on my webpage, which I can post a link to the blog entry if that is allowed?

Another lady arborist who was working with me at the neighbor's house this week gave me her thoughts on it, that the tree looked like it had been windsailed repeatedly over the years and perhaps some of the stranger-growing leaders coming out of the place where it had been topped should be removed.

I just struggle sometimes with pruning firs, especially ones that have been tinkered with so much already. The client may be open to having me come back and work on the top, but I only want to do it if it is really necessary.
 
What I've come up with is recommending 40-60 cycles of large conifers. With replacement trees being planted ongoing. Many trees older than that have grown with the protection of a forest being removed for development yadda yadda yadda.
 
"...perhaps some of the stranger-growing leaders coming out of the place where it had been topped should be removed.

or reduced.

"... The client may be open to having me come back and work on the top, but I only want to do it if it is really necessary.

Necessity depends on exposure to, and strength of, storms, but u knew that... There is always a high "target rating", as the tree has value, plus removal of a storm-wrecked tree would be costly.

http://www.isa-arbor.com/events/conference/proceedings/2013/DANKERS_Conifer_Care_Guidelines_2013.pdf

Hey--I found a version of his talk on the ISA website! I just love how he starts with roots, then restructures the tree from the top down:

AERATE the ground within the tree’s drip line/CRZ, carefully loosening a prescribed area of the soil
8 to 10-inches deep with a pitch fork, Air Spade, or water jet. Establish that the visible basal trunk is
where the buttress roots emerge from the ground and move away any excess dirt or debris piled
against the stem. Grass and invasive species will directly compete with the trees roots, so eliminate
any weeds around the trunk to enhance fine root function (Holers).
PRUNE only the parts of the canopy needing attention, NOT exceeding 15% of a healthy tree’s living
tissue. I recommend the Double-System Technique (DST) (See #9). Ascend to the highest,
structurally sound part of the canopy with redundant tie-in points. Inspect the top 10% of the tree for
its structural/growth pattern and only disturb this zone only if there are co-dominant tops. In the
middle 60% of the canopy, use a pole saw to suppress the longest limbs to a suitable, secondary
branch. Encourage downward-orientated branches, discourage upward growth, evaluate the multiple
tops/attachments, and check for trunk weaknesses. Use a secondary rope to lower large
limbs/hangers and retain it as an ANSI-required access line when working above 70-feet of height.
Secure the rigging with slings, carabiners, and assistance on the ground. Maintain the lowest 30% of
the lateral limbs to shade the roots, balancing their length with structural/clearance needs.
 
southsoundtree said:
Bump.


bad link in thread.
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Windsailing is crap, in our area Doug firs shed limbs, end weight on the lower 1/2 to 2/3rds can be beneficial.

I view pruning as directing growth. Kinda like those stress balls, you squeeze them and they pop out in other places.

Most conifers are highly competitive beings, in a dense stand they shoot up due to shading. Pruning can replicate this, directing growth as the tree wants more green stuff. So if one is wanting to do right for the tree, mitigate risk by reducing long limbs likely to break. Avoid as many removal cuts as possible as they increase the movement of the remainder.
 
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