Dear friends,

I would like any help suggested.

I am a landscape architect working in GREECE, currently involved in a project concerning the replanting of big trees, on a roof garden park, at the Opera house in Athens.

Please advise me if you know of any books or articles, regarding tree ancoring, to protect the trees from winds and also to avoid staking.

Thank you in advance,

Sincerely,

Thanos Sclavenitis
Landsca architec,
Athens, GREECE
topiodomi@otenet.gr

Reply to post by thanos sclavenitis, on December 05, 1998 at 06:09:10:

I'd be pleased to offer any help that I can. I am a landscape architect and certified arborist with a practice in central Florida (Orlando). We have a climate somewhat similar to yours.

I think highly of opinions expressed in "Establish and Maintenance of Landscape Plants" by Carl E. Whitcomb, PhD. published by Lacebark, Inc PO Box 2383 Stillwater Oklahoma, 74076, USA.

ISBN: 0-9613109-4-4.

Standard operating practice here is to not anchor trees up to about 4 inch caliper. We direct the contractors to anchor them in the contract, but don't enforce it. The understanding is that of the tree isn't stable, then the contractor is liable to come back and stake it. We have little wind, except for the occassional hurricane, and the sandy soil holds them in place pretty well.

In the event the trees needs to be staked I use a round post about 3 inch caliper and 8 feet long. 1 to 4 posts spaced evenly around the tree and driven in just outside the root ball. the tree is tied to the top of the post using a soft fabric tie with a knot that doesn't allow the tree to "roll" in the tie and be girdled.

For larger trees we use a lag screw screwed directly into the trunk with a diagonal guy (steel cable) to a ground anchor.

There have been a number of injuries due to persons tripping over the diagonal guy wires,and the need to be highly visible by encasing on a length of irrigation pipe, or other visually obtrusive manner. But it's better than a lawsuit.

Allow the trunk to move and stress in the breeze to avoid a weak stem development and to take the shock of a sudden wind. At the same time, it is necessary that the roots be firmly in place to avoid breaking off the small rootlets when being developed. We usually have close to 100% success ratio. Even the anchored trees can be have the anchors removed at the 1 year end of warranty date.
For larger trees over 4 inch caliper we

Reply to post by Paul M Davis, on December 05, 1998 at 06:09:10:


Hi,

It seems to me that the use of arial bracing in every way
is undesirable. It creates a trip hazard, it affects the
development of calliper and perhaps taper of the trunk, the
points of attachments (particularly lag screws) often do damage
at their best they are ugly and worrst of all more appropriate
techniques are available in 99% of the time.

Check the section in Arboriculture by Harris to see a system
developed by Chris Newman. If you would like to see some variations
of this I would be glad to help.

Lastly we should be specifying matterial with appropriate rootballs
to allow stability. We work with matterial from 600 to 600000kg and
seldom install a brace.

Mark

Reply to post by thanos sclavenitis, on December 05, 1998 at 06:09:10:

If you will place 2 timbers, perhaps 3x8's criss crossed under the root ball and extending well past the ball, then wires or cables can be attached to these and up into the tree for guying. The weight of the ball and soil is sufficient to keep the braces in place. I have done this many times on roof gardens.
Very treely,
lew

Reply to post by thanos sclavenitis, on December 05, 1998 at 06:09:10:

Thanos, you haven't described the situation well enough to offer firm suggestions yet.

What are the plant sizes- caliper, height, weight?

What is the planting medium? Pots, or beds? How large?

Does this have to be permanent, or can it be removed after the tree becomes established? What is the life-expectancy (of system or tree)?

As Lew suggested, a system that anchors to the substrate will be least obvious and still offer support. "Deadman" timbers below or alongside the root ball will work. Maybe even modifying the pots or bed floor to provide anchoring.

Russ

Reply to post by lewbloch, on December 05, 1998 at 06:09:10:


Hi Lew,

I get the ground anchor part. What I dont undersdand is why you
don't anchor the rootball to the ground rather than the tree trunk.
It seems to me that this is the natural model and is better for the
tree.

It also means no ugly cables. No trip hazards and if the system is not
removed over time there is little risk of damage to the tree.

In fact I am hard pressed to think of any reason to bring those cables into
the air apart from price and even then I'm not sure that maintenance has
been factored into the system.

Perhaps it is about time for a change?

Respectfully

Mark

Reply to post by Mark Hartley, on December 05, 1998 at 15:25:17:

I'll always willing to learn something new.

The diagram in Harris (as I recall) involved a deadman buried on both sides of the tree with wire cables passing over the top of the root ball.

I see advantages for this system in for a roof garden, or a situation that absolutely precludes above ground anchoring. (Perhaps the gentleman's Opera House would qualify?) I wouldn't recommend it myself, because I haven't personally tried it yet. I am interested in hearing about the experiences other persons.

It appears to me that the most evident difficulties would be:
1. Below ground interference with the installation or relocation of irrigation pipes, other site utilities, perhaps minor interference with eventual root development, and the eventual decay of the dead man (if consisting of wood). No doubt anyone operating a stump grinder 30-50 years in the future would have something to say about leaving wire cables buried in a root system.
2. The system relies upon tension upon the cable bearing directly down upon the top the root ball to prevent overturning. However, the force of overturning is not only upward, but also diagonally sideways. In order to effectivly resist the overturning force, the cable would need to be secured to the top of the root ball in some manner, the rootball would need to remain intact, and with the roots securely attached to the surrounding rootball soil. The cable would need to be supported by some obstruction that prevents it from digging into the top of a rain-softened rootball.
3. In our wind load zone the design of the system should withstand 100 mph winds with gusts to 140 mph.
4. It seems to me that the costs of excavation and installation would preclude it's regular use on most projects. Our guying system of vertical wood posts, with a horizontal tie, avoids the trip hazard of diagonal guying. They cost around $7 each. Diagonal guys on larger trees run about $18-20 each. These prices include materials and installation labor. The materials are completely removed after one year, and can be reused on other projects. Do you have a cost breakdown on alternate systems?

If you have a cad drawing or diagram that you would like to email to me, I would be keenly interested in reviewing it.

Reply to post by Mark Hartley, on December 05, 1998 at 19:08:53:

Mark,
Perhaps I assumed too much, but I did assume that these trees had large heads, subject to wind throw, therefore needing support. If this was not the case, why stake or guy at all? That is why I have the wires attached to the tree.
Very treely,
Lew

Reply to post by Paul M Davis, on December 05, 1998 at 18:51:37:

Paul, I have to disagree with you on several points. I'll take them in order:

1) As with any installed system, it must fit the current situation. The original question dealt with a roof-top garden. Irrigation may or may not be a problem, but a workaround can probably be found. In this situation, I'd be less concerned about irrigation pipes, etc.

I also doubt these trees will be there 30 to 50 years later. And I doubt a stump grinder will be working on the roof (but, hey, anything is possible ).

2) The wind force on the root ball is lifting on the windward, and compression on the lee side, or IOW, torque. If the root ball is indeed round, you have a problem. But if the cables are not placed over the fulcrum or pivot point of the root ball, they will effectively reduce the lifting effect and thereby prevent rotation of the ball. The anchor points should be as far out the roots as possible.

3) I doubt many 2x2 stakes with tie bands will stand up to 100 mph winds. And you pointed out that they were intended to be removed after one year, having done their job. The anchor system is still intended to assist with support for a limited time, until the tree can support itself.

4) Cost will be greater than a few stakes and wires. The ground anchors or deadmen will be a few dollars each. Add a few dollars for cables and hardware, depending on the system. The major cost will be the additional excavation needed, if the insatllation is in existing soil. In a roof-top planting, that may not be much of a problem.

Keep in mind that minimizing cost is not always the top priority, so the budget might allow for a little extra cost to maintain the decor.

Reply to post by Russ Carlson, on December 07, 1998 at 15:33:38:

Russ, I'm pleased to see that we disagree. That means that there is potential for one or both of us (and perhaps others) to learn something.

The initial request was for a book recommendation, which I hope was not terribly controversial. The rest of my posting is "fluff" about how we anchor trees around here, which precipitated the comment "the use of arial bracing in every way is undesirable".

I can see where the Harris diagram would have application for large transplants having a shallow, flat root configuration. I can also see its application for a roof garden, such as the gentleman is designing. Although perhaps in such an application the anchoring system might be required for more than just a few years, if the roots are too constrained to provide a natural anchoring support.

I was digressing to think of nursery stock having square (boxed), round (field dug) or cylindrical (container grown) shape. In each instance the height of the ball is approximately equal to the width. If anchored only with a cable passing over the root ball, torque would cause the tree to roll in the hole before lift on the windward side would become the primary force to be countered.

If someone has what they believe is a workable below-ground staking system for small to medium sized nursery stock, I would be very interested in seeing it.

Reply to post by lewbloch, on December 07, 1998 at 03:39:59:


Lew, thanks for replying. I too assumed that the trees had large heads and as small root
ball. That is why they required guying.

We both agree that guying and staking is less desirable than the tree standing up by itself. My question is
why then anchor the branches or trunk to the ground. Instead why not anchor the root ball to the ground? That way we only
affect the below ground portion. There can be no question that this is the best technique to use when we need to brace
but is by far the least used, perhaps because we are not as comfortable with it.

Your thoughts please

Mark

Reply to post by Paul M Davis, on December 07, 1998 at 21:31:21:


Paul,

You are correct that if a perfectly hemispherical root ball
is dug then this is harder to brace in this manner. The most
hemispherical rootball is that dug by the Newmans Tree Porter.
It is this machines inventor who Harris attributes as his source.

In pesonal comunications with Chris Newman, he has displayed systems
for bracing these henispherical 6 foot 6" rootball by adding a triangular
wooden frame beneath the root ball.

We have yet to have a failure with this system and we own both a Tree Porter
and a tree spade.

I find it ironic that we go to great lenths to point ou the disadvantages of
rigid staking and then go and guy a tree in this matter. As to costs, it is cheaper to
use spurs when pruning palms but its lousy to do so. This is no different. Quality must
be an issue allong with safety. Arial guying is a trip hazzard. People do sue and people
do mess with the cables. Out of sight out of mind as the saying goes

Back to you

Respectfully

Mark

Reply to post by Mark Hartley, on December 08, 1998 at 17:35:02:

That brings up a few good questions, Mark. Have you used the Duckbill anchors for this? The ones that are driven into the ground. I would think this system would work quite well for guying trees. Place the anchors before installing the tree, so the cables exit into the planting saucer. Set the tree, and attach the cables over the root ball. A turnbuckle or some other tightening device might be needed, or you could set it by driving the anchor after attaching the cables.

Has anyone tried this?

Reply to post by Russ Carlson, on December 10, 1998 at 02:53:19:


Hi Russ,

Yes I have tried duckbills but only the smaller size which can be easily
applied with a hand driver. The big machine driven ones would work well.
You need a swaging tool on site to shorten the length. Groeund screws work
well too.

Most of the stuff we do is on the big size sou ground anchors work great and
are inexpensive.

In fairnes to Lew Cobra have a lighter system available for guying that may be
more suitable than the old ridgid cable. Variable load springs like they use
on tents may prove a useful inline piece of hardware.

Mark

Reply to post by Russ Carlson, on December 10, 1998 at 02:53:19:

Mark and Russ,

1) Back in the thread someplace the concern was raised about possible future interference with large root growth, I suppose a taut cable cutting an expaning structural root. Would wooden stakes or deadmen lessen the problem (compared to Duckbills, screw anchors or other steel hdw.) because they tend to rot away leaving the cable 'floating' and lees taut?

2) Any guidelines on the ratio of ball dimension to top size which encourage such stability that it's less risky to have no bracing (and deal w/ occasional roll over) than to incur either A) expense of bracing removal and tripping incidents, or B) risk of girdling when cables are forgotten?

Scott

Reply to post by Scott, on December 11, 1998 at 16:32:08:

Let's design a system that will work.

How about a simple biodgradeable strap that fits over the root ball, arond the trunk. It would be sized to lay on top of the root ball. Install 3 or 4 ground anchors beyond the root ball, attach to the strap in the three or four points (triangular or square configuration), tighten as necessary. The degradeable strap will eventually rot away- depending on the material and soil moisture/temperature - And will leave the tree without root obstructions. THe inground hardware will not affect the tree in the long term, will not be seen, and will not be a tripping hazard. No cost to retrieve. Only additional cost is the hardware and installation time.

Remember the old adage about putting a $10 tree in a $50 hole, instead of the other way around- This just goes one step further, and guys the tree. Not recommended for all trees, of course, but if you need something that will support a tree, and be out of the way/ out of sight, this might do it.

Reply to post by Russ Carlson, on December 13, 1998 at 07:28:16:

Sounds good to me Russ. Patent pending?