Explanation of Terms
Below is a description of the terms that are used when you click on the forest community map. Unless otherwise mentioned, data in these tables was obtained from the USDA Forest Service's National Forest Inventory Database Retrieval System.
Area of Forest. The percentage of the total land area in a county that is forested.
Community Type 4. The four most common forest communities that occur in a county. A forest community is a group of species that frequently occur together. Not all species pictured with the community-type occur together all of the time.
County Name. The name of the county that was clicked
Estimate.
Foresters often do not measure every tree in an area. Instead they take plots
or samples of an area and use this information to calculate the total.
Forest Growth, State (%). This is an estimate
of how much the forests in a state are growing each year. It is based on
how much trees have grown in size between two time periods.
Forest Harvest, State (%). This is an estimate
of how much timber is being removed from the forest each year. Removals can
be the result of harvesting, land clearing or changes in land use.
Forest Mortality, State (%). This is an estimate
of how much of the forest has died between two time periods. Insects, diseases,
fire and combinations of environmental factors cause death of trees in the forest.
Number of Forested Plots. The number of plots that
were used to estimate the number and type of trees found in a county. The larger
the number of plots, the more accurate the data.
Number of Trees. This is an estimate of
the total number of trees found in a county. A tree is defined as a woody plant
at least 5 inches in diameter at a height of 4.5 feet from the ground.
Plot. The USDA Forest Service collects information
on small areas of land called plots. Each plot is roughly 1/6 acre in size,
and they are spread evenly across the county. On each plot, the tree species,
height, diameter, land-use (forest or non-forest), land ownership, and mortality
are recorded.
Private Forest Land. The percentage of the total
land area in a county that is owned by private individuals and corporations.
Public Forest Land. The percentage of the total
land area in a county that is owned by government. This includes local parks,
national forests, national parks, and Army bases.
State Name. The name of the state that was clicked.
Top 10 Species. The most important species found in
a county. How important a tree is depends on how abundant it is (number of trees)
and how dominant it is (how big). This data was obtained from http://www.fs.fed.us/ne/delaware/atlas/index.html
Year of Survey. This is the year that the last forest
survey was made in a state. It gives you an idea of how current is the data
presented in a table.