Over pruning of large Blue Gum Eucs

[Shaun Bowler]

Can anyone out here point me in the direction (literature) of the downside of over pruning large 100ft+ Eucs?
Thank you.

 

[NickfromWI]

Shaun- Does your info need to be species specific? That might be hard to find.

What is this for? Are you trying to show someone reason's why they should/shouldn't over prune their tree?

love
nick

 

[outofmytree]

Can anyone out here point me in the direction (literature) of the downside of over pruning large 100ft+ Eucs?
Thank you.

Hi Shaun.

Why not pm Ekka or Treeseer. I can tell you that mature trees must have, as a general rule, less pruning than immature trees but it sounds to me like you want a printed reference and I just don't know the best place to look. Eric operates in Australia and Guy in the US so if you need some local reference material perhaps Guy would be the better choice.

 

[Boa07]

Shaun, I think what you are asking about is dose...or rather the failure to apply proper dose to a mature tree (irrespective of the species).

You will find the Alex Shigo wrote quite a lot of information about what dose is and how to apply proper dose to trees....some of that info is (or was) freely available on the net... http://home.ccil.org/~treeman/shigo/index.html
Scroll down to article number one A professional understands dose.

Yes some Eucalypt species can produce a branch architecture that is most challenging when it comes to any significant pruning works, and the effects of urbanised soil conditions don't help one little bit!!!

 

[M.D. Vaden]

Can anyone out here point me in the direction (literature) of the downside of over pruning large 100ft+ Eucs?
Thank you.

There are a lot of nice big ones in north California.

Am curious about your question.

By saying "over pruning", it sounds like you might already have an idea of what excessive pruning is. So it sounds like you might be after documentation.

Or are you curious about how much pruning someone can safely get away with for a special need?

 

[Shaun Bowler]

Thanks

I don't have time to respond to your questions, until tomorrow because of work.
Thanks for the responces, I will get back to you.

 

[treeseer]

Write the WCISA.

Don't ask me; I'm not a euc man.

:rockn:

 

[Shaun Bowler]

Here is the situation.
3/4 mile city streets. Large easement for growth(@20ft.) 100-140ft BGEs, spaced about 60 from each other, trees are approx 80 years old.
Million dollar + homes all under these trees. (I will post some pictures tomorrow.)
These trees are currently being pruned every 3 years wether they need it or not. The way the contractor is pruning them is to remove all the watersprouts, and taking off huge limbs to the trunk, (Dia-48") in the belief this will give the tree more stability.
To give the perception to the homeowners that live in these neighborhoods that now... the tree is safe. Until 3 years pass.
We have a big problem with drought here in the SF Bay Area.
The SFBA will begin mandatory water rationing soon. Physild has been defoliating/killing eucs here for years.
What I have told the City is that what is happening by this 3 year cycle of major limb removal, plus the removal of all the water sprouts is in fact weakening the tree, from top to bottom.
There have been no tree failures.
Could you tell me what you think?
PS
I am a CA&CTW for the City. I have been up in these trees many times.

 

[Shaun Bowler]

photo #1

 

[Shaun Bowler]

photo #2

 

[jomoco]

photo #1

Holy mackerel!

Too late for any reprieve on those trees!

Once a blue gum has been butchered like that, the butchery must continue in order to maintain any degree of acceptable safety, and every 3 years is about right.

Even pruning a blue gum to class 1 standards invariably provokes a massive suckering response. Blue gums are one of the most sensitive trees to over pruning than almost any other euc in the 1500 species+ euc family.

Much like oaks, virgin blue gums should have only their deadwood and structural faults attended to.

Blue gums are very bad trees to have in high foot traffic areas as it is natural for them to shed large branches more than capable of killing someone under them.

jomoco

 

[Shaun Bowler]

last photo

 

[jefflovstrom]

Those trees should be removed.
Jeff

 

[Little Monkey]

i would recommend a 100% reduction

 

[M.D. Vaden]

One photo had some trees in the background with more leaves. Are those some of them?

Or are they all like the ones with the bones picked pretty clean?

 

[pdqdl]

Apart from how to trim, etc, why do they want to keep the trees at all? Those are pretty ugly trees, and they don't look like they would cast any shade at all.

Given that they sound like a sucking economic void of perpetual trimming expense, wouldn't it be cheaper to cut 'em down and be done with it?

 

[Ekka]

Could you tell me what you think?

I'll tell you no worries what I think.

Here's the picture.

The trees have been mutilated.

Whilst that species of euc typically takes a while to decay it never the less does decay. However in my experience the problems are beneath the ground.

Rather than repeat a bunch of stuff I have already written about I'll post a copy with a link.
Source:http://www.weareallabouttrees.com.au/pruning.html

it's important you understand the species that it applies too, not all trees can take it. Generally the species are deciduous (drop leaves for winter) and because pollarding removes all growth it's good to have a species that atleast has become accustomed to being defoliated. These deciduous trees store energy for the spring burst of leaves and shoots so they are better able to recuperate from a 100% prune. Some of the suitable species are willow, lime, ash, field maple, holly, hornbeam, oak, plane and beech. See something familiar? You dont grow those up here! We're in a subtropical environment not temperate.

The euc needs a foliage/root ratio to live. When it's defoliated then it relies upon it's stored reserves to sprout, in drought guess what, many die!

Then the tree also needs a certain amount of foliage to sustain the root system and hopefully do some compartmentalizing, when it cannot some roots die and decay and some of the foliage dies off too.

The multiple wounds become pest condo's, a huge signal is broadcast ... "yo bugs, huge banquet here".

A myriad of bugs come, sap suckers, borers etc. The tree is trying it's best to deal with the heavy dose of pruning but now the bugs well that's getting a bit much.

However, the trees are deemed more stable from an engineering perspective as they have less weight on extended lever arms and smaller sail. Yeeha, engineers win the day because the probability of failure is now reduced ... for a while.

The maintenance costs and the prize view of these mutilations is now raising eyebrows. Is this OK because we judge it from an engineers perspective and as long as the tree lives it's OK? Were there other options?

Yes, I have spoken a lot about pruning eucs and the difficulty in reduction pruning them. Long extended self lions tailed leaders that once established are very hard to do much about other than thinning ... and thinning on the tips not cutting the inner branches out.

So what has happened here is an unsuitable species was planted in the that spot for the task etc. Even lots of formative pruning at a young age would have been labour intensive to get a shorter more compact tree.

So now you are in the maintenance mode. The pruning regime of 3 years might drop to 2 years, dead wood will have to be watched, tree stability at ground level is a concern if decay sets in especially on any leaning trees.

It's the negative spiral now.

The difference between doing that to a small tree and large tree is the sheer volume of the vascular cambium that tree has to support. You see all that wood, well that's a lot of work keeping that shell alive.

Here's a smaller euc we thinned and formative pruned to give you an idea.

Now what I would suggest if retention of those trees is desired is some soil treatments. If need be bore a hole through concrete or road to inject area on frequent basis (maybe 6 monthly).

This is not a fertilizer boost program but a soil conditioning with mycorrhizal fungi, ensure you incorporate silica or silicon in that mix as it hardens cell walls and leaves etc making it tougher for chewing and sucking insects.

Thought to be given to future pruning regime's frequency and trying not to prune everything off, keep some foliage on, try to manage a newer smaller crown, evergreens are just that ... they need leaves.

 

[Shaun Bowler]

One thing I forgot to put into the description/condition of these trees is that every spring sulfur conks show up on the trunks.
Multiple car accidents have caused trunk wounds.
Going back to my original question, is the repeated over pruning of these trees effecting the root structure/stability of the tree?
Where can I find literature to present?
These tree are still standing due to Heritage Tree Ordinances.
Thank you very much for the responces!

 

[Ekka]

Any literature is not going to be tree and site specific. You may find generalized stuff ... there's tons of it, but it is just that. I have added one from a reputable source.

You need to get own evidence and facts.

 

[outofmytree]

Taking aside the obvious issue of money for work done, what is the rationale behind removing the bulk of foliage from the top of the tree? I am serious in asking this question as I have seen it done to a nice row of Liquid Amber here in Perth. Is there ANY plausible reason why any mature tree could be pruned this way?

Same tree closer view

The saw hands in the bucket referred to this as "tipping" and said they had done it 2 years before on the same trees. Note the apparently healthy Liquid Amber in the back ground, on the north side of the same park.