Movement and work in the tree using DdRT and SRT with the ZIGZAG

Installing the work rope:

• The arborist selects an anchor on-site and installs it as high as possible in the tree, for optimal movement.
• Provides tree access for multiple arborists
• The access rope can be used for rescue or as a work aid by the person on the ground.

• The top of the tree must be reached before work can begin.

SRT

• • Ability to work anytime during access.
  • Ability to work without climbing to the tree-top.
  • The rope may be set up on a releasable anchor, to facilitate rescue.
  • Difficult to check anchor quality before use.
  • Using an anchor set by the throw line, which is not necessarily the best nor the best placed.

Efficiency and ergonomics when returning to the trunk:

• Pulling on the brake-side rope in double mode provides a self-hauling effect. The rope serves as a fulcrum and reduces the effort needed to climb.
• Without a special setup, the arborist pulls 100% of his weight when pulling on the rope.

Load on the anchor:

Ddrt

• The arborist is suspended directly; the load on the anchor is simple.

SRT

• The load on the anchor is theoretically doubled by the “pulley effect” at the rope’s redirect point (depending on the friction at the redirect).

Note: this point will be elaborated in another technical tip as practice can differ significantly from theory.