Deadwood
Risks
Wood that has been dead for some time may have extensive decay .
Deadwood throughout the canopy may be decayed or poorly attached . The presence of deadwood is not necessarily in itself a significant risk - in many species , deadwood may stay ‘ hard ’ and structurally sound for decades . Recent deadwood may be safer to climb than living branches or stems .
Consider the size ( diameter and length ) and location of the dead branches and what risk they may pose .
In some species deadwood becomes unstable very quickly .
Deadwood can be accidentally dislodged while installing lines , while moving through the tree or while extracting the casualty , possibly causing a struck-by injury to the rescue climber or ground crew .
Control measures Avoid loading if possible .
Load test if possible – look for evidence of decay and watch for deadwood dislodged whilst setting lines or ascending .
Brace , strap , cinch or guy if necessary .
Remove loose deadwood around casualty before beginning extraction .
Decay
Risks
Decay may significantly weaken the structural timber of the tree .
Structural failure may occur at low and unpredictable loads .
Decay is the process of decomposition of organic tissues by fungi or bacteria - in the case of trees , it will normally cause a reduction in the structural integrity of the tree at that point .
Decay can be extremely hard to detect , and some types of decay can rapidly reduce the integrity of a tree . Look for evidence such as fungal fruiting bodies , trunk swellings , deadwood , cavities and previous failures .
Decay at base or in structural roots may result in whole tree failure under low and unpredictable loads .
Control measures Avoid loading if possible . Load test if possible .
Brace , strap , cinch or guy if necessary .
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