thresholds
(1) in Integrated Pest Management. pest population levels requiring action. (2) in hazard assessment. risk assessment and risk management. levels or risk requiring action.
through-hardware
cable anchors or bracing rods that pass completely through an oversized. pre-drilled hole in a trunk or branch and are secured with nuts and washers (contrast with dead-end hardware).
through-pruning
in utility line-clearance pruning. directional pruning that removes branches from the center of the tree crown to provide clearance from utility lines. leaving selected overhanging branches above.