2.5.3 Strapping a split tree
Recent splits that have occurred during the tree accident may be highly unstable . The application of this technique to cracks which have occurred just a few minutes earlier has not been tested in working practice .
Checklist to consider before strapping a crack to access a tree :
Is there access for an aerial rescue appliance , MEWP or crane that will avoid the need to climb the tree ?
Is it possible to use a floating anchor or similar tie-in-point to avoid the rescuer being secured into the compromised tree ?
Where tree trunks have split or cracked longitudinally , their structural integrity may have been compromised by up to 50 %.
Tree workers sometimes use straps or chains to cinch up longitudinal cracks in trunks and stems . If sufficient force can be applied , the loss of structural strength caused by the fault may be somewhat mitigated .
The use of strapping techniques should only be considered when all other possibilities for accessing the tree have been exhausted .
Strapping should be used as a safety factor , rather than a way of climbing a tree that otherwise would not be safe to climb . When performed by tree workers , it is usually in trees that have been split for some time , at the least for several days . If the split was a pre-existing condition that occurred before the accident in the tree took place , it may not be of significant concern .
If the tree is to be strapped and climbed , can the forces remain within normal tree tolerances ?
Where possible , test tree stability before and after strapping by using a pulling line or similar . Strapping should result in a significant and noticeable difference in tree movement .
The first strap should be installed around the trunk below the lowest point of the split to prevent further delamination . Only then can the rescuer continue to ascend the trunk . Once the rescuer ’ s lanyard is approximately one foot past the first lanyard , another lanyard must be installed , usually as high as the rescuer can efficiently reach .
The rescuer can then ascend past that strap , and repeat the process until the casualty is reached or the rescuer can begin climbing the ‘ safe side ’ of a delamination . See Bottom-up rescue on a partially failed stem , Pg . 191 .
Double wrapping the straps or chains may increase their effective strength when working with larger trees .
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