The Southern Coastal Plain
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Natural stands susceptible to SPB attack in the Coastal Plain are characterized by high
stand densities, a large proportion of pine sawtimber, and declining radial growth.
Outbreaks occur most frequently in stands located on poorly drained soils and low-lying
areas. Trees on dry or droughty soils are less commonly attacked. Rating systems have been
developed for east Texas; the Kisatchie National Forest in Louisiana; corporate timberland
in Texas, Louisiana, and Mississippi; and forests in south Arkansas.
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Natural stands susceptible to endemic SPB attack in the Piedmont are well-stocked pine
stands with a large percentage of the host component in shortleaf pine, slow radial growth
during the last 10 years, and a high clay content in surface and subsurface soils. Two
systems have been developed for ranking the susceptibility of natural stands to SPB attack
in the upper Piedmont of Georgia. The first is a predictive equation that includes
variables easily measured or often contained in existing inventories; the second is a
system designed for use in the field by service foresters.
Table 1. - Characteristics of stands susceptible to SPB attack.
|Southern Coastal Plain
|Densely stocked stands
||Densely stocked natural stands
|Large proportion of sawtimber
||Large proportion of overmature sawtimber
|Declining radial growth
||Slow radial growth during last 10 years
||Slow radial growth
|Poorly drained soils and low-lying areas
||High percentage of clay in surface and sub-surface soils
||Dry, south-facing slopes
|High percentage of shortleaf and/or loblolly pine in the stand
||High percentage of shortleaf pine in the stand
||High percentage of shortleaf and/or pitch pine in the stand
The Southern Appalachians
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Studies in the mountains of Georgia, North Carolina, South Carolina, and Tennessee have
shown that stands severely attacked by the southern pine beetle were densely stocked, slow
growing, and had a large proportion of overmature pine sawtimber. Shortleaf pine and pitch
pine were more susceptible to beetle attack than Virginia pine and eastern white pine.
Systems are currently being developed to rank the susceptibility of natural stands in the