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Outbreak Source Data

These annual county-level data describe southern pine beetle outbreaks with varying levels of resolution over time. The earliest data consist of binary outbreak status, where outbreak is defined as one southern pine beetle spot per thousand acres of host forest type. A more refined categorical measure ("disc") was first used in 1978. In most states a continuous measure ("smacre") is available since 1990.

Spots are usually identified by either state or National Forest specialists using aerial overflights. Several overflights may be conducted per year. Spots smaller than perhaps 10 trees are usually not reported as they often go inactive without intervention. Ground checking of spots may be needed to confirm that southern pine beetle is the causal agent.

These data have been collected for four editions of this report, with data retained and expanded in each iteration. Each state has used its own procedures for collecting and reporting their information, and these procedures may have changed over time.

fspot

Spots reported to be on national forest lands

sspot

Spots reported by the state specialists as having occurred on lands other than national forests

tspot

The total number of spots in a county, the sum of fspot and sspot

acres

Host forest type acres, drawn from Forest Inventory and Analysis survey data, and defined as acres in either the loblolly/shortleaf or oak/pine forest types (more...)

smacre

Spots per thousand acres of host forest type, reports as a continuous measure the intensity of outbreak level

disc

A discrete measure of outbreak level, as determined by the following cutoffs of smacre:

• 0 = less than 0.1 spots per thousand acres
• 1 = 0.1 to less than 1 spot per thousand acres
• 2 = 1 to less than 3 spots per thousand acres
• 3 = three or more spots per thousand acres
• 9 = indicates more than 1 spot per thousand, as indicated by a bin value of 1

bin

A binary measure where "1" indicates outbreak, equivalent to a disc value of 2 or 3 or where smacre is 1 or more

year

Calendar year during which spots form and are identified

fips

Federal Information Processing Standard code that uniquely identifies a county

state

Two character state abbreviation

cntyname

Name of the county