Use of multiple guy lines
A single guy will not inhibit lateral movement , and the tree can still fail if it moves across the line of the guy ( Image A ). This is unlikely to be a significant concern for rescuers when dealing with leaning trees . It may be applicable if the tree is loose in the ground but does not have significant lean , or if it will be loaded heavily in several directions during the rescue process .
By installing two guys on the up-lean side of the tree , with a minimum angle between the guys of approximately 30 ° or more , lateral movement is inhibited ( Image B ).
This technique may also be useful if the ideal anchor is not available , or if the direction of fall of the tree cannot be determined , for example if the tree is leaning in one direction but deflected in a different path by an obstacle , branches , or the action of its remaining root system .
Front guying
The technique of front guying , or front stabilisation , would be familiar to all rescuers experienced in road-crash rescue or structure rescue .
In the image above , a static front guy has been installed to allow the primary back guy system to be brought to a high tension with no risk of causing the tree to stand back up . Front guying should be considered wherever there is a risk of the tree being ‘ stood up ’ by excessive guy line tension .
- 216 - © Arboriculture Australia 2022