Hazard A hazard is a likely source of harm ; a situation or condition that may result in personal injury , property damage , or disruption of human activities . In tree management , a hazard is a tree or tree part that has a reasonable likelihood of failure that would cause damage or injury .
Hierarchy of risk control measures
High Visibility clothing ( High Vis or High Viz )
Hinge
The hierarchy of risk control measures is a tool used when determining how risks are to be managed , or when selecting between risk control measures .
Clothing that is made in specific bright reflective colours . Class D is for daytime use only ; Class N has reflective strips and is for day , dusk and night use .
A strip of wood fibres created between the scarf and the back cut that helps control direction in tree felling or limb removal .
Hinge control The ability of the hingewood to prevent the tree from falling sideways during a felling operation . When the hinge is completely broken hinge control is said to be lost .
Hingewood See Hinge above . Hung-up trees Trees which have become lodged in other trees and are wholly or partially suspended . Included bark
Bark present in the union between two stems , inhibiting the interlocking of the xylem and potentially decreasing the strength of the union .
Input force The force applied initially to a system .
Internal stresses ( in timber )
Karabiner
Knotted strength ( of rope or slings )
The forces of tension and compression which are present in timber as it is suspended or twisted under load .
Oblong metal ring , used in climbing and static rigging that is opened and closed by means of a spring-loaded gate .
The reduced strength of a particular cordage type when a knot is incorporated into the loaded section .
Lanyard A length of cordage which is used to connect two points . Lead The part of the rigging line from the rigging point to the load . Leverage
Lowering device
The multiplication of bending force achieved by the use of a lever arm pivoting around a fulcrum .
A device used to create and manage friction in the lowering line ( load line ) in rigging operations .
Mechanical advantage A system by which effort can be multiplied . MEWP Mobile Elevated Work Platform .
Minimum breaking strength or MBS
Also known as minimum break strain and usually expressed in kilonewtons ( kN ), this figure is the load above which an item of lifting equipment can be expected to fail when new and when used in the correct configuration ; this number will drop rapidly i . e . the equipment will break much sooner than expected when using old , worn , damaged or mis-configured equipment .
Moment The twisting action caused by a force acting some distance from a pivot point . Moving block In a mechanical advantage pulley system , the pulley that moves . Moving rope anchor point
A moving rope anchor point is part of a rigging system where a loaded rope makes an angle and can be supported but will still be able to move freely across that angle ; examples include pulleys , rigging rings , tree unions , rigging blocks .
PLB Personal Locator Beacon – an emergency signalling and location device . Portawrap
PPE
Prusik hitch
Brand name of an instrument attached to the base of a tree in rigging ; used to take wraps with the load lines to provide friction for controlled lowering line .
Personal Protective Equipment includes clothing or other articles like helmets that may help to protect the wearer in the event of an accident .
A type of multi-wrapped friction hitch used in climbing and rigging ; used to attach the prusik loop to the climbing line when footlocking .
Prusik loop A loop of rope used to form a prusik hitch for climbing or rigging . Prusik minding pulley
Pull line
A specific type of pulley configured with extended cheek plates to keep a prusik hitch from jamming in the sheave .
A tagline or a line tied near the top of a section of tree or the top of a tree to be removed and used to help pull the top in the desired direction .
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