Rating the Susceptibility of Stands to Southern Pine Beetle Attack

G.N. Mason - Research Coordinator, IPM RD&A Program for Bark Beetles of Southern Pines,
P.L. Lorio, Jr. - Project Leader and Supervisory Soil Scientist, Forest Insect Research, USDA Forest Service, Southern Forest Experiment Station, Pinesville, LA,
R.P. Belanger - Principal Silviculturist, USDA Forest Service, Southeastern Forest Experiment Station, Athens, GA, and
W.A. Nettleton - Entomologist, Forest Pest Management, USDA Forest Service, Southern Region, State and Private Forestry, Pineville, LA.

Integrated Pest Management Handbook, USDA, Forest Service, Agriculture Handbook No. 645, April 1985.

Model Summaries - Piedmont Risk

Description	Piedmont Risk is a qualitative system for categorizing the likelihood of SPB spot occurrence and spot spread, and the need for treatment to reduce these likelihoods. The system utilizes site/stand data from the Piedmont region of South Carolina and Georgia.
Inputs	1) Pine component (percent shortleaf) 2) Slope (percent) 3) Clay content (percent in surface soil)
Outputs	1) Likelihood of spot occurrence (Risk) 2) Likelihood of spot spread (Hazard) 3) Timber loss potential and need for cultural treatment 4) Economic loss potential
Step I.	(1) Pine component:	> 50% shortleaf?	Yes or no
	(2) Slope:	slope > 10%?	Yes or no
	(3) Clay content:	> 28% clay?	Yes or no

 

Step II.
To estimate the likelihood of spot occurrence, check the line on Table 1 with the combination of inputs from above.

Table 1 - Likelihood of spot occurrence.

Pine component	Slope	Clay content	Spot occurrence
			Value	Class
Yes	Yes	Yes	3	High
Yes	No	Yes	3	High
No	Yes	Yes	3	High
Yes	Yes	No	2	Med
No	No	Yes	2	Med
Yes	No	No	1	Low
No	Yes	No	1	Low
No	No	No	1	Low

 

Step III.
To estimate the likelihood of spot spread, select the value for the appropriate basal area.

Table 2 - Likelihood of spot spread.

Pine basal area (ft²/ac)	Spot spread
	Value	Class
> 120	3	High
90-120	2	Med
< 90	1	Low

 

Step IV.
To determine timber loss and need for stand treatment, add spot occurrence value (from Table 1) and spot spread value (from Table 2):

Spot occurrence value + spot spread value = timber loss value.

Table 3 - Timber loss potential and need for cultural treatment.

Timber loss value	Timber loss potential	Cultural treatment need
6	Very high	Extreme
5	Medium high	High
4	Medium	Medium
3	Medium low	Low
2	Very low	Very low

 

Step V.
To estimate economic loss potential, add timber loss value (from Table 3) and product value. The product value for pulpwood (</-9 inches d.b.h.) is 1; the value for sawtimber (>9 inches d.b.h.) is 2.

Economic loss value = loss value + product value

Table 4 - Economic loss potential.

Economic loss value	Economic loss potential
7-8	High
5-6	Medium
3-4	Low

 

General Reference	Hedden and Karpinski 1983.
For additional information, contact	Dr. R.L. Hedden Department of Forestry Clemson University Clemson, SC 29631 Telephone: (803) 656-3302

[ Back ]