Refers to the era prior to European settlement of North America, especially to the period before industrialization made it possible for these settlers to induce unprecedented ecosystem changes.

A usually metal chain used to measure length and distance. Less commonly used in land surveys than a Gunter's or surveyor's chain, the Ramsden's or engineer's chain is 100 feet in length, with 100 1-foot links. The terms "engineer's chain" and "Ramsden's chain" apply primarily to the measuring utensil itself and not to any particular unit of length.

1. A measurement used in the United States Public Lands Survey System (PLSS), consisting of a strip of land six miles wide, running in a north-south direction.
2. A row or tier of townships lying east or west of the principal meridian and numbered successively to the east and to the west from the principal meridian. Abbreviated as R1E (range 1E), R2E (range 2 east), R1W (range 1 west), and so on.

A point in history that is considered to be representative of the natural conditions of an ecosystem. This point, which may be in the past or present, is chosen such that it is within the historic or natural range of variability for a particular area.

A pattern of regular or semi-regular occurrences or processes that characterizes and governs a natural system, as in precipitation regime, fire regime, disturbance regime, etc.

The planting of trees under silvicultural prescriptions in areas where trees were once located but no longer exist due to disturbance (harvest, fire, wind, insects, etc.).

A unit of length used in land surveys. The terms, rods, poles, and perches are equivalent and may be used interchangeably, although "rod" is the most common. One (1) rod is equal to 25 links, 16.5 feet, or 1/4 (0.25) chain. For conversions and examples, see Rod, pole, or perch equivalents and conversions and the various Converting rods, poles, or perches to... entries.

A rod is a unit of length used in land surveys.
One (1) rod is equal to one (1) pole or perch.
One (1) rod is equal to 16.5 feet.
One (1) rod is equal to 0.25 chains.
One (1) rod is equal to 25 links.
One (1) rod is equal to 0.025 furlongs.
One (1) rod is equal to 198 inches.
One (1) rod is equal to 5.5 yards.
One (1) rod is equal to 0.0031 miles.
One (1) rod is equal to 502.92 centimeters.
One (1) rod is equal to 5.0292 meters.
One (1) rod is equal to 0.00503 kilometers.

Unit of area measurement equal to 1/4 (0.25) acre, 40 square rods, or 10,890.0 square feet. For more rood conversions, see rood conversions or equivalents or converting roods.

One (1) rood is equal to 1/4 (0.25) acre. One (1) rood is equal to 40 square rods. One (1) rood is equal to 2.5 square chains. One (1) rood is equal to 10,890.0 square feet. One (1) rood is equal to 1,210.0square yards. One (1) rood is equal to 0.2959 arpents. One (1) rood is equal to 0.0004 sections or square miles. One (1) rood is equal to 0.00001 townships. One (1) rood is equal to 1,011.7141 square meters. One (1) rood is equal to 0.1012 hectares. One (1) rood is equal to 0.001 square kilometers.

The number of years required to grow trees to an ideal size or age; usually trees are grown to either economic maturity or natural maturity.

Generally, temperature decreases as elevation increases. For every 1,000 foot increase in elevation, temperature decreases three (3) degrees Fahrenheit, and vice versa. As latitude becomes more northward in the Northern Hemisphere and more southerly in the Southern Hemisphere, temperature decreases. The general rule is that temperature changes three (3) degrees Fahrenheit for every 300 mile change in latitude at an elevation of sea level. These temperature changes influence greatly the diversity and abundance of plant and animal species from place to place. However, other factors such as soil, topography, aspect, and precipitation are also extremely important in determining the types of plant and animal life that occur in any given area.

See "Surface runoff".

A measure of merchantable timber in live trees of merchantable species. Generally, sawlogs should be a minimum of eight inches (8") diameter at breast height (dbh) and eight feet (8') in length.

Live trees of merchantable species that are suitable for harvesting and sawing into lumber according to specific criteria. Generally, sawtimber should be greater than eight inches (8") diameter at breast height (dbh), and should contain at least one (1) sawlog. Merchantable sawlogs are usually a minimum of eight feet (8') in length.

A section is a tract of land approximately one (1) mile square and containing 640 acres, within a township. Sections are used in the government rectangular survey system (U.S. Public Lands Survey). Each section is approximately 1/36th (0.0278) of a township. Irregularities exist due to the curvature of the earth; these irregularities are corrected for in the northern and western tiers of sections in each township. One (1) section is equal to 640 acres, one (1) mile square, one (1) square mile, and 27,878,400 square feet.

One (1) section of a township is one (1) mile square and has an area of one (1) square mile. One (1) section is equal to 640 acres. One (1) section is equal to 27,878,400 square feet. One (1) section is equal to 2.59 square kilometers. One (1) section is equal to 3,097,600 square yards. One (1) section is equal to 102,399.59 square rods, poles, or perches. One (1) section is equal to 6,399.9744 square chains. One (1) section is equal to 2,560.0 roods. One (1) section is equal to 757.5523 arpents. One (1) section is equal to 0.0278 (1/36th) townships. One (1) section is equal to 2,589,988.1103 square meters. One (1) section is equal to 258.9988 hectares.

The practice of manipulating and controlling forest establishment, growth, composition, structure, and to a certain extent, function. Silviculture can be thought of as agriculture for the forest, with trees as crops.

The characteristics of a site that influence growth of vegetation, including soil chemical and physical properties, climate, aspect, elevation, topography, and disturbance regime.

A unit of area measurement (square measure) that is one (1) Gunter's or surveyor's chain in length on each side. There are ten (10) square chains in one (1) acre of land. One (1) square chain is equal to 4,356.0 square feet or 404.687 square meters.

One (1) square chain is equal to 4,356.0 square feet. One (1) square chain is equal to 484.002 square yards. One (1) square chain is equal to 404.687 square meters. One (1) square chain is equal to 16.0 square rods, poles, or perches. One (1) square chain is equal to 0.4 roods. One (1) square chain is equal to 0.1184 arpents. One (1) square chain is equal to 0.1 acres. One (1) square chain is equal to 0.0405 hectares. One (1) square chain is equal to 0.0004 square kilometers. One (1) square chain is equal to 0.0002 square miles or sections. One (1) square chain is equal to 0.000004 townships.

A unit of area measurement (square measure) that is one (1) foot long on each side. One (1) acre of land contains 43,560 square feet. One (1) square foot is equal to 0.09 square meters.

One (1) square foot is equal to 0.0929 square meters. One (1) square foot is equal to 0.1111 square yards. One (1) square foot is equal to 0.0037 square rods, poles, or perches. One (1) square foot is equal to 0.0002 square chains. One (1) square foot is equal to 0.00002 acres. One (1) foot is equal to 0.000009 hectares. One (1) square foot is equal to 0.00009 roods. One (1) square foot is equal to 0.00003 arpents.

A common unit of metric area measurement that is one (1) kilometer in length on each side. One (1) square kilometer is equal to 1,000,000 square meters, 100 hectares, or 0.386 square miles.

One (1) square kilometer is equal to 1,000,000 square meters. One (1) square kilometer is equal to 100 hectares. One (1) square kilometer is equal to 0.3861 square miles. One (1) square kilometer is equal to 247.10538 acres. One (1) square kilometer is equal to 10,763,910.42 square feet. One (1) square kilometer is equal to 1,195,990.046 square yards. One (1) square kilometer is equal to 39,536.703 square rods, poles, or perches. One (1) square kilometer is equal to 2,471.044 square chains. One (1) square kilometer is equal to 988.422 roods. One (1) square kilometer is equal to 292.4926 arpents. One (1) kilometer is equal to 0.0107 townships.