- Parent material
- The mineral or organic matter from which the upper layers of soil are formed.
- Park-like structure
- Stands with large scattered trees and open growing conditions, usually maintained by natural ground fires.
- Partial retention
- A tree harvest method that removes only part of the stand. (See High Grading.)
- Peak Flow
- The highest amount of stream of river flow occurring in a year, or from a single storm event.
- Downward flow or infiltration of water through the pores or spaces of rock or soil.
- Perennial stream
- A stream that flows throughout the year and from source to mouth.
- Personal use
- The use of a forest product, such as firewood, for home use and not for commercial use.
- Planning area
- The area of National Forest land covered by a Regional Guide or Forest Plan.
- Planning period
- The 50 year time frame for which goods, services, and effects were projected in the development of the Forest Plan.
- The stage of forest succession in which trees are between 3 and 7 inches in diameter and are the dominant vegetation.
- Pole timber
- Trees at least 5 inches in diameter, but smaller than the minimum size for sawtimber.
- Precommercial thinning
- Removing some of the trees from a stand that are too small to be sold for lumber or house logs, so the remaining trees will grow faster.
- Prescribed fire
- Fire set intentionally in wildland fuels under prescribed conditions and circumstances. Prescribed fire should be used to mitigate the suppression of natural fires.
- Management practices selected to accomplish specific land and resource management objectives.
- A computer model for timber growth and yield. It projects per-acre growth and volume yield for commercial timber stands.
- Public domain lands
- The territory ceded to the Federal government by the original thirteen states, plus additions by treaty, cession, purchase and theft.