Prefield methods: streamlining forest or nonforest determinations to increase inventory efficiency

Interior West Forest Inventory and Analysis has developed prefield protocols to distinguish forested plots that require field visits from nonforested plots that do not require field visits. Recent innovations have increased the efficiency of the prefield process. First, the incorporation of periodic inventory data into a prefield database increased the amount of information available for making accurate forest or nonforest determinations. Second, acquisition of low-altitude aerial photography proved to be a cost-effective method of verifying forest or nonforest status. Third, tools based on geographic information system technology have decreased the time required to complete the prefield process. Comparisons of field data with prefield determinations verify the prefield process as a cost-effective method of focusing data collection efforts on forested plots.