Modeled mountain pine beetle basal area loss - 2006

The 2006 National Insect and Disease Risk Map (NIDRM) Project integrates 188 individual risk models constructed within a common, consistent framework that accounts for regional variations in current and future forest health. The 2006 risk assessment, conducted within the contiguous United States and Alaska, provides a consistent, repeatable, transparent process through which interactive spatial and temporal risk assessments can be conducted at various scales to aid in the allocation of resources for forest health management. This modeling process is intended to increase the utilization of forest health risk maps within and outside the National Forest System and encourage development of future risk maps.

NIDRM is a composite, consisting of 188 individual risk models. These models are built to portray the expected loss of basal area for each agent and its corresponding host. That loss of basal area relates to risk of mortality via the definition of risk: "the expectation that, without remediation, 25 percent or more of the standing live basal area (BA) of trees greater than 1 inch in diameter will die over the next 15 years (starting in 2005) due to insects and diseases."