The following warning signs may be seen during testing :
Failure or partial failure
Movement of the branches at the anchor point
Movement of the lower structure
Movement of the tree in the ground
Loose branches or hangers
Insect swarms or other hazards
Watch for small branches breaking as well as failure of the tree structure . Watch for hangers or dead branches being dislodged .
Excessive movement can be a clear indicator of an unsuitable anchor point . Where an anchor has a large range of movement under working loads it may be too thin or too far out on a branch .
Trees grow to attain equal distribution of mechanical stress through their structures . If a tree under load has a particular area that is visibly bending or flexing more than the surrounding structure , it is probably an area of structural weakness and should be investigated further .
Any movement of the tree in the ground under simulated rescue loads is a major warning sign . Root rot fungi or mechanical damage that has compromised the structural roots may make the whole tree unsafe to climb .
Movement of the tree provides an opportunity to spot , and possibly to dislodge , any loose branches or hangers .
Movement of the tree may cause insect swarms to become active . Of particular concern are paper wasps and similar common tropical species .
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