| Lumber Glossary Term |
Definition |
| Underbrush |
The brush under a stand of timber. |
| Undercut |
A wedge-shaped notch cut in the base of a tree to govern the direction of its fall. This is also known as a box or a notch. |
| Underlayment |
A layer of plywood or other manufactured board used as a base material under finished flooring. Underlayment is often used as a substrate to increase the strength and/or smoothness of the flooring. |
| Uneven-Aged Management |
A Silvicultural system in which individual trees originate at different times and result in a forest with trees of all ages and sizes. Harvest cuts are on an individual-tree selection basis. |
| Unloaded Deflection |
The vertical distance between the chord and the unloaded skyline, measured at mid-span. |
| Unmerchantable Wood |
Material that is unsuitable for conversion to industrial wood products due to size, form, or quality. May include rough, rotten, and dead trees; the tops, limbs, and cull sections fro, harvested trees; or small and noncommercial trees. |
| Upper Stem Portion |
Saw timber tree bole extending from above the merchantable top to as minimum four-inch top diameter outside bark or to the point where the central stems break into limbs. |
| Utility Knife |
A cutting tool used in various trades and crafts for a variety of purposes. Designed to be lightweight, easy to carry and use. |
