USDA Forest Service

Forest Health Protection, Southern Region


USDA Forest Service
Forest Health Protection
Region 8
1720 Peachtree Road, NW
Room 816 N
Atlanta, GA 30309

Phone: (404) 347-7478
Fax: (404) 347-1880

United States Department of Agriculture Forest Service.

USDA Link Forest Service Link


The 2012 National Insect & Disease Risk Map

In 2006, the USDA Forest Service, State & Private Forestry, Forest Health Protection (FHP) unit published the second National Insect and Disease Risk Map (NIDRM). The publication, individual maps and much background information can be viewed at:

Built using a GIS framework, 1-kilometer resolution host tree species maps, and ancillary data such as climate, topography, soils, pest occurrence, etc., were used to model the risk of mortality for individual pest agents. The resulting maps were combined to display composite risk of mortality of 25 percent or more of forest basal area over a 15-year period.

The 2006 National Insect and Disease Risk Map--Composite Risk.

The 2006 National Insect and Disease Risk Map--Composite Risk.


Technology advances and forests change; and a new revision of the NIDRM is underway with a projected completion date of 2012. GIS data layers are being completely updated at a finer resolution of 240-meters with many of the layers being re-sampled from 30-meter host and climate data. FHP’s Forest Health Technology Enterprise Team (FHTET) is leading the effort with assistance from USDA Forest Service regions and staff of many State Foresters. Tapping a large and diverse team of experts is essential in making technology represent biology in a realistic way.

The 240-meter host species layers form the foundation of individual risk models. FHTET constructed representative layers for host tree species using satellite imagery, Forest Inventory & Analysis (FIA) field data and other data layers such as climate and topography. Final host layers will contain species attributes such as frequency and distribution, basal area per acre, trees per acre, quadratic mean diameter and a stand density index. Initial versions of host layers are currently under review by Federal and state personnel. This will include the collection of field data from various areas that will help to verify predicted parameters such as basal area and quadratic mean diameter. Feedback from field visits will be used to adjust models and improve host layers.


Modeled longleaf pine frequency in southern Alabama and Mississippi.

Modeled longleaf pine frequency in southern Alabama and Mississippi.


Technology is also making risk modeling easier, quicker and more intuitive. FHTET has produced a software program, the Risk Map Application (RMAP), which allows regional teams of Federal and state insect and disease specialists to readily produce and modify risk models for individual pest/host combinations. Modelers can almost immediately see the resulting output and add, subtract, and modify factors contributing to risk, thus adjusting models based on known science and professional knowledge.


Screen shot of Risk Map Application.

Screen shot of Risk Map Application.


Important pests that will be addressed by the Southern modeling team include annosum root disease, beech bark disease, butternut canker, Dutch elm disease, emerald ash borer, fusiform rust, gypsy moth, hemlock wooly adelgid, laurel wilt, oak wilt, red oak decline, Sirex wood wasp, southern pine beetle and white pine blister rust. Others may be added as necessary. There may be insufficient data to create good models of some pests. In those cases, maps illustrating a special concern will be created using whatever data is available to best display the risk or threat to southern forests. Many southern pests are east wide in their distribution and whenever appropriate, southern and northeastern specialists will collaborate to build models that seamlessly display risk.

Once individual models are complete and reviewed, a composite map will be constructed by summing the mortality risk of the various agents. Acres at risk to mortality can then be tallied and displayed. Further periodic revisions to the risk analysis are a certainty given the rapidly-changing nature of forests and pest threats, especially the threats from introduced and invasive pests which often have rapid and devastating effects.

Southern Region NIDRM contact:

Dale A. Starkey, Plant Pathologist and
Southern Forest Health Monitoring Program Manager

USDA Forest Service, Southern Region
State & Private Forestry, Forest Health Protection
Alexandria Field Office
2500 Shreveport Hwy.
Pineville, Louisiana 71360
Voice: 318-473-7293
Fax: 318-473-7292

Last update: September 2010



USDA Forest Service - Forest Health Protection, Southern Region
Last Modified: Monday, 16 December 2013 at 14:18:28 CST

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