Typically, the amount and type of pruning that is necessary is based on:
- Tree species
- Growth rates (how fast the branches grow back)
- Wood strength (the chance of the branch breaking under the load of strong wind, snow, or ice) -Conductivity (how well the wood can conduct electricity)
- Branch size (Larger-diameter branches coming in contact with conductors by failure or deflection create the greatest risk for tree-related interruptions)
- Voltage conducted by the line and the line’s construction (the higher the voltage, the greater the clearance required)
- Framing and spacing between phases of multi-phase lines (compact design and multi-phase lines pose a higher risk to tree-related interruptions)
- Location of a tree in relationship to protective devices and critical customers on the circuit (hospitals, etc)
- Location of a tree in regards to general public safety (existence of tree houses, public places, climbing ability of tree, etc)
- Risk of wildfire ignition