Forest Inventory and Analysis
at the North Central Research Station

FIA Inventory

Originally, the region's forests were inventoried one State at a time, progressing from State to State until all the forests in the region had been surveyed and the cycle began again. These periodic inventories began in the 1930's, and most of our States have been inventoried at least four times since then.

In 1998 Congress mandated that we switch from periodic to annual inventories. In an annual inventory, about 20 percent of the plots in a State are visited every year and each plot is revisited every 5 years. This annual inventory system allows for completed regional coverage every year and a 5-year reporting cycle. Concurrent with the switch to annual inventories, we began to assess forest health by incorporating the plot component of the National Forest Health Monitoring Program.

To learn more about FIA Inventory click here.

Timber Products Output

TPO is a survey based system that was originally devised to provide an estimate of current removals from timberlands. Because of the periodic nature of past FIA field surveys, they could only provide an estimate of average removals. TPO was developed to provide another estimate for removals and also to provide further information as to where the wood was processed and into what product category.

To learn more about Timber Products Output (TPO) click here.

Containment and eradication strategies were developed in the battle against the Emerald Ash Borer infestation that was discovered near Detroit in July 2002 by using TPO data and maps.   

To learn more about the Emerald Ash Borer click here.