Basic tree care concepts - Petzl USA
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Basic tree care concepts

Warnings

  • Read the technical notice before viewing the following techniques.
  • It is important to fully understand the information provided in the technical notice before using this complementary information
  • Mastering these techniques requires training.
  • Consult a professional before attempting to perform these techniques on your own.

Belay system

A belay system includes at least an anchor and potential accessories (false crotch...), a belay support (rope, lanyard...), a rope adjuster and its connection to the harness. When two belay systems are required, each element of the first system must be independent of the elements of the second system.

Tree access

The access phase begins on arriving at the base of the tree and ends when the work rope is installed on a primary anchor. Generally, the arborist begins by throwing a line over a high branch.

This line is used to install the access rope used for the ascent.

Aligning the ends

When installing a doubled access rope, the strands of the throw line must be “aligned”: the arborist ensures that the two strands run side-by-side and aren’t separated by one or more branches.

Work phase

The work phase includes moving around in the tree to get to the cutting points, and cutting.

Movement

While moving around, the arborist can use a single belay system installed on a primary anchor. Depending on national legislation, a second belay system is recommended, or mandatory, when the rope of the primary system is inclined at more than 45°.

DdRT Doubled Rope Technique

Movement technique using one doubled rope, with a redirect point at the anchor. Attention: the rope is “doubled” but it is a single belay system. The rope is mobile: it is constantly moving between the anchor and the arborist, as he/she moves around.

SRT Single Rope Technique

Movement technique which also enables access, using a single rope anchored to a fixed point in the tree, or to the base of the tree. The rope is fixed and does not glide; the arborist moves along the rope.

Cutting

When using any cutting tool, the arborist must use two independent belay systems.

Friction hitches

Friction hitches are the traditional arborist tools. Numerous types exist for different usages.

The hitches must be learned through training and always tied with the utmost care.

The primary characteristic of a friction hitch is to be "living":

  • The same knot grabs and slides differently depending on the situation and how it is tied.
  • The same knot grabs and slides differently depending on the ropes used.

False crotch

A false crotch is an anchoring device installed around the trunk or a branch. It allows better rope glide and avoids damaging the branch itself.

Tree anchor

The concept of the tree anchor must be understood through specific arborist training.

Primary or definitive anchor

Passing around the trunk (axis 1) or around the largest branches in certain situations (axis 2).

During the work phases, the arborist must have at least one belay system installed on a primary anchor.

Supplementary anchor

Passing around any branch that can hold the arborist's weight.

A supplementary anchor can be used to install a second (supplementary) belay system or a positioning lanyard.

Connectors

Depending on national legislation, it is recommended, or mandatory, to use double auto-locking connectors (TRIACT-LOCK, BALL-LOCK...) in tree care work. In the various situations of cantilever loading, such as blocking around a branch, use steel connectors.