How to avoid stormy trajedy/treewise

Discussion in 'Woody Plants' started by jamkh, Jan 3, 2007.

  1. jamkh

    jamkh Active Member

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    Vancouver, Canada
    How to avoid stormy tragedy/treewise

    KarinaL & Summerlily,
    I seek your kind approval to start this discussing as a new thread as it does depart from plants and touch more on Engineering but nevertheless related to plant stability.
    Ones concern should be raised to extreme when we are faced with unprecedented volumes of rain. In many cases the ground has turned mushy; it's like trying to support a high-rise building with a liquid cement foundation.
    We should all pool our minds and come out with as many possible solutions to make tall plants more stable under very wet and stormy conditions.
    Here then is my contribution. I had stated that when a tree topples, it traces the action of a first class lever. I was wrong because it is actually behaving like a 3rd lever with the effort applied in the middle. The root ball acts like a base plate or at least as far as the area where the main lateral roots resist bending. Looking at the problem from an engineering point of view, can we devise a mechanism to shore up the plant's stability. Here is the area where we can have our creative or inventive minds put to the test.
    First we need to check with the weather-man if we can predict with a fair degree of accuracy the direction of the prevailing wind. If not (like in tornado prone areas/where you take it as fated) then the structure you need to invent becomes more complex as you are looking at a 3D instead of a 2D aspect.
    The simplest and a rather ugly solution is to tie a strong steel cable up the main trunk as high as possible without risking trunk fracture and ground the cable in line with the wind direction.
    Can we then create stability and incorporate aesthetics at the same time.? One good way is to increase the base plate of the root ball by extension in all directions (#3D effect). How is this done?
    First examine the lateral roots and determine the points where you believe the bending may occur. Then measure the distance of these points from the base of the trunk for example like y feet. Then you go to the ironworks people and purchase 4 very strong and thick steel girder beams of lengths measuring within the range of 4 to 6 y feet. Measuring from the center of each beam, make two points at 5/8 or 6/8 of y feet one on each side of center.Then you drill 4 rivet holes about 3/8 or 1/2 inch diameter at each point on all 4 girders. Then you further drill 4 rivet holes at the ends of each beam and at points 1&1/2y feet measured from center ( if your beam's length is 4y feet; more if you start with a longer beam). These 16 rivet points become your anchors to the ground. For anchor posts you need 16 lengths of the same size as your lateral beams, each of length 1/2 y feet or 3/4 y feet if your tree height is more than 3 y, or y feet if your tree height exceeds 6y feet. Bury these anchors in massive cement blocks at the correct 16 locations to coincide with the locking 16 outer points on your lateral beams. Do not cement first but rivet first all your beams both lateral and vertical , then only cement. The lateral beams can be buried but just deep enough to touch the top of these lateral roots without exerting any pressure on them. I hope you get a mental picture as I shun drawing any diagrams if i can get away with it. I appreciate this remedy can be termed as labor intensive and expensive; but isn't your life priceless?
    I feel confident these cement anchors more than compensate for the loosened nature of saturated soil we are now faced with. I welcome readers to contribute your expertise or your originality/imagination
    I would request readers to kindly respect all contributions without any criticisms on the functionality of their concepts. This would ensure a congenial atmosphere and help us concentate on the issue at hand. Thank you.
    Last edited: Jan 6, 2007
  2. smivies

    smivies Active Member

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    Kingston, Ontario, Canada
    Good are a couple of additions...

    - the concrete anchor idea won't be enough to resist the swaying. The anchors will either rotate in the ground or eventually pull out of the ground. A system to engage the mass of earth around the anchor is required. A mass of concrete (~2' diameter)buried ~3-4' below the surface with the cable working in tension only (no rotational forces on the concrete) would work. Another idea would be to drive 8-10' long steel I-Beams (4"x2.5" should do) into the ground at an angle perpendicular to the cable angle

    - three anchors would do (like a tripod). Anchor the cables at least 20' up the tree and keep the angle of the cable shallow (anchors would be >20' away from the trunk)

    - disconnect the cables in spring & reconnect in early fall before the really wet weather. The roots and trunk need the sway to encourage root & trunk diameter growth during the growing season (ask any Euc owner). Incorporating a heavy spring in the cables might work too.

    - remove the whole assembly after ~5 years.

    - get a qualified and experienced arborist to plan and install the whole project & get more than one opinion.

  3. jamkh

    jamkh Active Member

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    Vancouver, Canada
    Re: How to avoid stormy tragedy/treewise

    Another observation which needs to be factored in your equation of levers. In one sense the timing of the November storms is Providence sent as they hit when our deciduous plants are dormant. I believe the damage would have been multiplied many folds had these storms hit when the plants had the summer foliage. With global warming the weather patterns are changing and I shall not be surprised if a storm of hurricane strength hit us in summer. I certainly wouldn't want any trees around which come into striking distance from my house.
    Another interesting point is to seek legal opinion on the liability of the owners if their tree damage their neighbor's or city properties. The city itself may become liable for insisting that every household should plant at least one large tree in the garden. Presently I believe such incidents have been classed under an "Act of God", which term allows insurance companies to escape liability.
    Other interesting observations may come into play when we anticipate tree storm damage; however Nature does give us a helping hand.
    (a)Have you ever wondered why different species have different root systems? Some come with tap roots, (mostly deciduous) others just fibrous roots (pines. etc). The reason is the shape and type of the leafy canopy. In pines the tree is tall and the shape is conical. I recall jimmyq's thread on lever where he places the fulcrum at the lower region of the trunk. The cone lowers the center of gravity and creates better stability whereas the broom shape raises it. Yet an exception can be seen in pinus pinea (stone pine) which features an umbrella shaped canopy. With very tall evergreen trees, the canopy is always spread out with wide open areas for the wind to sail through. Also pines trees crowd and grow well together in clumps or in forest and a fibrous root system allows for greater interlocking for stronger anchorage. Thus a lone standing pine is weaker for its anchorage. Deciduous plants have tap roots and large , long lateral roots to anchor as they don't like crowding and the canopy is top heavy and dense by comparison (an good example is The London Plane tree).
    (b) Trees growing in areas with prevailing strong winds have their roots growing larger and longer against the direction of the prevailing winds. Also the trunk shows a thickening of the circular rings on opposite sides in the wind direction. This explain why trees in Eastern Canada can withstand strong winds better than in the West as they have adapted to the strong prevailing winds as mentioned here. This is especially true when we consider trunk fracture.
    (c) Usually tall trees have single trunk, more so if the shape is conical. Beware when you see pines with two trunks, you can expect one to fracture at the point of junction. When you prune a branch of deciduous trees heavily, you get profuse branching; but you need to thin out these branches to 2 or 3 branches and eventually to a single branch to prevent a lopsided look and weight.
    Last edited: Jan 6, 2007
  4. jimmyq

    jimmyq Well-Known Member 10 Years

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    Metro Vancouver, BC, Canada.
    some reference for the legal issues:
    Arboriculture and the Law in Canada, Dunster and Murray
    some reference for wind effect on trees: Ed Gilman has research on this matter and is available via the University of Florida, possible on their website as well.
    The Hillier book of tree planting and management, Keith Rushford
    Arborist certification study guide, ISA Press
    Photographic guide to the evalution of hazard trees in urban areas, Matheny and Clark
    Trees and Development; a technical guide to preservation of trees during land development, Matheny and Clark
    Fungal strategies of wood decay in trees, Mattheck, Engels & Schwarze
    Wood decay fungi, Christopher Luley
    Common tree diseases of british columbia, All, Morrison & Wallis
    Parasitic microfungi of western trees, Funk
    Foliar fungi of western trees, Funk
    Illustrated guide to pruning, Ed Gilman
    Any book by Alex Shigo

    I list these as reference for ways to identify, evaluate and mitigate trees that may be more susceptible to failure. Many ( I hesitate to say most) of the trees that failed in the last month were examples of poor structure, super saturated soils or victims of internal decay prior to the excessive wind event. Proper identification along with accepted mitigation practices couldl ikely have prevented much of the damage that occured from their failures.

    as an aside, Ed Gilman has done research with the Davey Tree company regarding aerodynamic responses of trees and foliage but I dont know if its available for public consumption yet, I am looking forward to seeing it thats for sure.

    in regards to tap roots and fibrous roots yes, I agree that it is species divided but... in general trees do not have tap roots, they may have deep roots depending on soil conditions.

    here is a drawing from the Morton Arboretum, drawn by an artist during an excavation and removal of a tree.

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