1. Tree Removal – working on a tree with the goal of taking it down entirely, including the brush, limbs, and wood.
2. Tree Preservation – working on a tree with the goal of maintaining and keeping it. Tree preservation usually includes one or more of the following activities: trimming, pruning, cabling, bracing, fertilizing, guying, enforcing tree and root protection zones, etc.
3. Tree Trimming – selective removal of branches and sections of tree to accomplish pre-determined objectives, including for example: clearance from structures or utility lines, aesthetics, preemptive hazard mitigation etc. The end-goal of trimming is usually subjective, meaning that the work to be performed can be difficult to specify on paper, and usually needs pictures/diagrams to be communicated, or to be pointed out in person.
4. Tree Pruning – selective removal of branches according to predetermined rules and standards. Pruning activities usually include a. deadwood, b. weak or broken branches, c. crossing/rubbing/interfering branches, d. watersprouts and suckers, etc. The end-goal of pruning is usually objective, meaning that the work to be performed is fairly straightforward to communicate, and all parties can agree when the specified work has been completed.
5. Rigging – use of ropes to lower and control sections of tree to the ground. The opposite of rigging is free-falling the pieces to the ground, which is usually faster.
6. Natural crotch rigging – running the ropes straight through branch unions/crotches in the tree to speed up production, increase friction, and allow for easy retrieval of lines when finished. While being a very productive old-school technique in tree work, natural crotch rigging is hard on ropes and trees, and should not always be used in situations where the tree is being preserved.
7. False crotch rigging – running the ropes through dedicated rigging hardware such as blocks or rings. This, combined with good rigging system design, allows for efficient tensioning, lowering, and lifting of branches and wood. Rigging hardware must be removed from the tree when the work is finished, of course.
8. Rigging System – interaction of all elements used for rigging, including points in the tree, slings, hardware, rope, force angles, etc.
9. Piece – the section of tree being rigged.
10. Rigging Line(s) – main rope(s) used to hold the weight of the piece.
11. Tag line(s) – secondary rope(s) used to control swing or directionality.
12. Positive/Overhead Rigging – rigging point is above the piece, used whenever possible. Positive/overhead rigging, when combined with pre-tensioning of rigging lines, reduces or eliminates the dynamic loading on the rigging system, minimizing peak forces.
13. Negative Rigging – rigging point is below the piece, used in the absence of other options. Always involves shock loading/dynamic loading.
14. Shock Loading / Dynamic Loading – mass coming to a short, sudden stop, or taking an uncontrolled/fast swing. This can multiply peak forces by 10X or more.
15. Static Loading – when the rigging system is loaded in a slow and controlled manner, the load experienced (peak force) is equal to the mass of the piece being rigged. This is the ideal rigging scenario, and is the opposite of shock loading/dynamic loading.
16. Peak forces – the maximum load that the rigging system experiences while rigging a piece. Peak forces can greatly exceed the weight of the piece being rigged when that piece takes a drop or a swing.
17. Tension wood – wood fibers are being pulled apart.
18. Compression wood – wood fibers are being squeezed together.
19. Leverage – bending force being exerted at a distance from a fulcrum.
20. Mechanical Advantage – force amplification achieved by using a tool, mechanical device or machine system. In our line of work, this is usually achieved using ropes and pulleys, although there are other options, including come-alongs. Mechanical advantage always involves a trade-off: pulling distance for pulling power.
21. Friction – the force resisting the relative motion of solid surfaces sliding against each other. Friction produces heat which can damage both ropes/hardware as well as tree bark. Friction management is a key component to many aspects of tree climbing and rigging.
22. Bend Ratio – when running a rope through a block or pulley, the minimum ratio of sheave to rope diameter is 4:1. This means that if we are using 1/2″ rope, the sheave must be at least 2″ in diameter. A more preferable ratio, as recommended by Samson Ropes, is 8:1, for maximum strength retention of the rope, meaning that a 1/2″ rope would be used with a pulley sheave diameter of 4″.
*** See also: Language of the Ropes – Tree Climbing