The role of pre-field operations at four forest inventory units: We can see the trees, not just the forest

The Forest Inventory and Analysis (FIA) program attempts to inventory all forested lands throughout the United States. Each of the four FIA units has developed a process to minimize inventory costs by refraining from visiting those plots in the national inventory grid that are undoubtedly nonforest. We refer to this process as pre-field operations. Until recently, the pre-field process of differentiating forest from nonforest plots received very little attention or scrutiny. No national pre-field manual currently exists, nor does any other form of formal documentation of the pre-field process. Prefield specialists from all four FIA units gathered in December 2007 to discuss the role of pre-field operations, to identify national commonalities, to share techniques and technologies, and to explore opportunities to increase efficiency and expand functionality. The meeting revealed that each of the four FIA pre-field teams serves the same two fundamental roles: 1) identifying plot locations that are potentially forested and therefore require visitation by a field crew, and 2) subsequently preparing field materials. Each pre-field team currently practices some form of quality assurance, yet no common procedures exist regarding pre-field quality assessment and quality control. Participants agreed that additional information could be derived from the photointerpretive aspect of this process via the collection of land use and crown cover data from all FIA plots, including those that are not visited by field crews. Such information might facilitate estimates of nonforest conditions with trees, e.g., urban forest, and landuse changes, e.g., the development of formerly forested lands. This paper documents the current status of pre-field operations, suggests areas for future process improvements and collaboration among the four FIA units, and evaluates the potential of the pre-field process to provide additional information to the inventory.