Support protection


Published on

Published in: Education, Technology, Business
  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Support protection

  1. 1. Tree Support and Protection Systems Mark Wachter Resource Forester Missouri Department of Conservation Certified Arborist #MW-4340A
  2. 2. Overview <ul><li>Arborists’ Certification Study Guide </li></ul><ul><ul><li>Cover chapter 9 objectives and key terms </li></ul></ul><ul><ul><li>Workbook questions and sample test questions </li></ul></ul>
  3. 3. Introduction <ul><li>Cables or braces are installed in trees to provide extra support by limiting the movement of limbs. </li></ul><ul><li>Any time hardware is installed in a tree, there will be wounding and the risk of decay. </li></ul><ul><li>Hazardous trees cannot be made safe by the use of cables. </li></ul>
  4. 4. Cable Installation <ul><li>Cables are installed in trees to limit movement of limbs judged to have a week connection or to support heavy limbs by connecting two or more limbs together. </li></ul><ul><li>Additional support may be needed due to split or decayed crotches, crotches with included bark, or inherent danger of weak-wooded trees. </li></ul>
  5. 5. Cable Installation <ul><li>Before installing cables or braces, the tree should be properly pruned to remove hazardous limbs and to reduce the weight of the limbs to be cabled. </li></ul>
  6. 6. Splits such as this may be candidates for support with a cable and brace rod.
  7. 7. Splits such as this may be candidates for support with a cable and brace rod.
  8. 8. Heavy limbs may be candidates for cabling.
  9. 9. Cabling Hardware <ul><li>Two cable types </li></ul><ul><ul><li>7-strand, common-grade galvanized </li></ul></ul><ul><ul><ul><li>More bendable </li></ul></ul></ul><ul><ul><li>Extra-high-strength (EHS) </li></ul></ul><ul><ul><ul><li>Much stronger, but less flexible </li></ul></ul></ul><ul><ul><li>Sizes of 3/16-inch to 3/8-inch diameter </li></ul></ul>
  10. 10. Cabling Hardware <ul><li>Dead-end hardware (one end exposed) </li></ul><ul><ul><li>Lag eye </li></ul></ul><ul><ul><ul><li>Anchor with a closed eye </li></ul></ul></ul><ul><ul><li>Lag hook, or J-hook </li></ul></ul><ul><ul><li>Sizes of 5/16-inch, 3/8-inch, ½-inch, and 5/8-inch </li></ul></ul><ul><li>Refer to ANSI A300 for hardware limitations </li></ul>
  11. 11. Left and right lag hooks.
  12. 12. Cabling Hardware <ul><li>Lag hooks are installed by screwing into a pre-drilled hole that is smaller in diameter than the lag. </li></ul><ul><li>Drill hole 1/16-inch to 1/8-inch smaller than the lag. </li></ul>
  13. 13. Cabling Hardware <ul><li>Dead-end hardware </li></ul><ul><ul><li>Works good on small limbs with hard wood. </li></ul></ul><ul><ul><li>Do not install in limbs greater than 8 to 10 inches in diameter. </li></ul></ul><ul><ul><li>Do not install in limbs with decay. </li></ul></ul><ul><ul><li>Must seat the full length of the threads. </li></ul></ul>
  14. 14. Cabling Hardware <ul><li>Through-hardware (both ends exposed) </li></ul><ul><ul><li>Eye bolts </li></ul></ul><ul><ul><li>Threaded rods with amon-eye nuts </li></ul></ul>
  15. 15. Threaded rod with amon-eye nut (top); eye bolt (bottom).
  16. 16. Cabling Hardware <ul><li>Through-hardware </li></ul><ul><ul><li>A hole 1/16-inch to 1/8-inch larger than the hardware is drilled through the limb to be cabled. </li></ul></ul><ul><ul><li>Eye bolt or threaded rod is installed with a round washer and nut on the outside end. </li></ul></ul><ul><ul><li>On very thick bark, the bark should be chiseled away to countersink the washer against the sapwood. </li></ul></ul>
  17. 17. Cabling Hardware <ul><li>Washers </li></ul><ul><ul><li>Eye bolts and threaded rods must be anchored with washers and nuts. </li></ul></ul><ul><ul><li>Heavy-duty round washers are recommended. </li></ul></ul>
  18. 18. Cabling Hardware <ul><li>Thimbles </li></ul><ul><ul><li>Must be used when attaching cable to anchoring hardware. </li></ul></ul><ul><ul><li>Purpose is to protect cable from excessive wear. </li></ul></ul>
  19. 19. Cabling Hardware <ul><li>Dead-end grips </li></ul><ul><ul><li>Used to attach EHS cable to hardware. </li></ul></ul>
  20. 21. Cabling Tools and Equipment <ul><li>Come-along </li></ul><ul><ul><li>Brings two branches together. </li></ul></ul><ul><li>Cable grip </li></ul><ul><ul><li>Used to pull cable to proper tension. </li></ul></ul><ul><li>Cable aid </li></ul><ul><ul><li>Used to spread open thimbles, to tighten lags, and help wrap dead-end grips onto the cable. </li></ul></ul>
  21. 22. Cabling Tools and Equipment <ul><li>Ship auger </li></ul><ul><ul><li>Works well in green wood and pulls shavings from hole. </li></ul></ul>
  22. 24. Attaching Cable to Hardware <ul><li>Eye splice </li></ul><ul><ul><li>Used for 7-strand, common-grade cable. </li></ul></ul><ul><li>Cable clamps </li></ul><ul><ul><li>Alternative to using an eye splice. </li></ul></ul>
  23. 25. Installation Techniques
  24. 26. Cables should be installed at least two-thirds the distance from the crotch to the branch tips.
  25. 27. The cables should be installed perpendicular to an imaginary line that bisects the crotch.
  26. 28. The hardware should be installed in direct line with the pull of the cable.
  27. 29. The hardware should be installed in direct line with the pull of the cable.
  28. 30. Cabling systems.
  29. 31. Hardware installed in trees should be no closer together than a distance equal to the diameter of the limb.
  30. 32. Only one cable should be attached to each anchor.
  31. 33. Much of the holding power comes from wood that forms after installation.
  32. 34. Installation Techniques <ul><li>Anchors should not be installed into decayed areas. </li></ul><ul><li>The installation of cables in a tree represents an ongoing responsibility. </li></ul><ul><li>Cables must be checked annually. </li></ul>
  33. 38. Nonrigid Support Systems
  34. 40. Bracing <ul><li>Used to reinforce weak or split crotches, or to strengthen decayed areas. </li></ul><ul><li>Bracing is used in combination with cabling, not as a substitute. </li></ul>
  35. 41. Bracing <ul><li>Two types of steal rods </li></ul><ul><ul><li>Lag-threaded rods </li></ul></ul><ul><ul><ul><li>Can be installed as dead-end hardware. </li></ul></ul></ul><ul><ul><ul><li>Drill hole 1/16-inch to 1/8-inch smaller than diameter of rod. </li></ul></ul></ul><ul><ul><ul><li>Advantage is threaded rod itself provides support. </li></ul></ul></ul><ul><ul><li>Machine threaded rods </li></ul></ul><ul><ul><ul><li>Used in soft-wooded trees, or decayed wood. </li></ul></ul></ul><ul><ul><ul><li>Drill hole 1/16-inch to 1/8-inch larger than diameter of rod. </li></ul></ul></ul>
  36. 42. Threaded rod with nuts and washers.
  37. 43. Bracing <ul><li>To support a crotch that is not split: </li></ul><ul><ul><li>A single rod is installed above the crotch. </li></ul></ul><ul><ul><li>Place 1 to 2 times the branch diameter above the crotch. </li></ul></ul><ul><ul><li>Additional braces may be installed below the crotch, if necessary. </li></ul></ul><ul><li>To support a split crotch: </li></ul><ul><ul><li>Install rod below crotch and through the split. </li></ul></ul>
  38. 47. Guying <ul><li>Guying of trees tends to be permanent because tree will not produce the necessary roots or wood to support itself. </li></ul><ul><li>Ground anchors should be placed no closer to the trunk than two-thirds the distance from the ground to the lowest attachment in the tree. </li></ul><ul><li>Guys should be attached about two-thirds the height of the tree. </li></ul><ul><li>Guys can present a hazard to pedestrians. </li></ul>
  39. 48. Lightning Protection <ul><li>Some trees more likely to be struck: </li></ul><ul><ul><li>Trees alone in an open landscape </li></ul></ul><ul><ul><li>Tallest trees in an area </li></ul></ul><ul><ul><li>Trees on a hill </li></ul></ul>
  40. 49. Lightning Protection <ul><li>Which trees to protect? </li></ul><ul><ul><li>Historic trees </li></ul></ul><ul><ul><li>Trees of great economic value </li></ul></ul><ul><ul><li>Large trees within 10 feet of a structure </li></ul></ul><ul><ul><li>Trees in recreational areas, golf courses </li></ul></ul><ul><li>Protected trees are not intended to directly protect people from lightning and are not considered safe havens in storms. </li></ul>
  41. 50. Lightning Protection <ul><li>A lightning protection system consists of a series of copper conductors that extend from the top of the tree, down the main braches and trunk, and out beyond the tree underground where they are grounded. </li></ul>
  42. 51. Lightning Protection <ul><li>Air terminal </li></ul><ul><ul><li>Copper or bronze point located near top of tree </li></ul></ul><ul><li>Main conductor </li></ul><ul><ul><li>Copper cable connected to air terminal and running down main branch and the trunk. </li></ul></ul><ul><ul><li>Attached at regular 3 feet intervals with approved attachments. </li></ul></ul>
  43. 53. Lightning Protection <ul><li>Main conductor </li></ul><ul><ul><li>Support systems (cables) should be connected to lightning protection system. </li></ul></ul><ul><ul><li>Conductor cable should extend out from the tree and be buried 8 to 12 inches below ground. </li></ul></ul><ul><ul><li>System still functional if tree grows around conductor as long as there is no break in the conductor. </li></ul></ul>
  44. 54. Lightning Protection <ul><li>Ground rod </li></ul><ul><ul><li>Conductor cable attached to copper ground rod that is 10 feet long and ½-inch diameter. </li></ul></ul><ul><ul><li>Ground rod should be driven to a depth of 10 feet. </li></ul></ul><ul><ul><li>In dry, sandy, or rocky soils, the cable should be forked to several ground rods. </li></ul></ul><ul><ul><li>For soil with less than 2 feet of depth, use a ground plate. </li></ul></ul>
  45. 55. Lightning Protection <ul><li>All hardware should be approved by the National Fire Protection Association or the Lightning Protection Institute. </li></ul>
  46. 57. In dry, sandy, or rocky soils, the cable should be forked to multiple ground rods.
  47. 58. Ground plate.
  48. 59. Summary <ul><li>Workbook questions and sample test </li></ul>
  49. 60. Questions