2.4.6 Lanyard compression injuries
Lanyard compression injuries occur when a climber is attached from Side-D to Side-D around a stem which subsequently delaminates , usually during felling .
There are several reasons for vertical delamination in this fashion . Fast-growing tree species with a high proportion of cellulose fibres are vulnerable to delamination . Heavily leaning stems , stems felled just above a union , or stems with cavities or decay below the cut are all vulnerable to vertical delamination during felling rather than following the hinge .
Shallow , acute scarf ( face ) cuts or undercut or overcut scarf cuts will also increase the likelihood of this occurring .
Lanyards attached from Side-D to Side-D form a circle , with the back pad of the harness being part of that circle . As the stem delaminates , the arborist is constricted against the stem . If the delaminated face does not fully separate from the remaining stem , the rescue team may arrive to find the arborist trapped against the trunk with their lanyard still tensioned by the partially collapsed tree . Several rescues of this type have been undertaken in the last decade in Australia alone .
Lanyard compression rescue scenarios
Scenario 1 : cut section stable , rescue anchors available
The image on the left is based on a recent accident attended by a vertical rescue team .
A tree worker was felling a large , leaning stem close to the ground , using a shallow step cut rather than a scarf . As they put in the back cut , the stem delaminated instead of hinging .
When the rescue team arrived , the arborist was suffering severe compression injuries and their lanyard adjustor was impossible to free . The arborist ’ s climbing line was set in the tree above them , and the cut piece was resting on the ground but still partially attached to the tree .
The rescue team was able to secure the arborist to other available anchors in the tree , then chose to cut the lanyard to free the arborist . There was no need to either secure or cut free the stem to perform the rescue .
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