The Remaining Fifteen Percent
With more than 600 million square miles, Alaska is the largest state in the United States. The state’s interior boreal forests, spanning more than 170,000 square miles, are equally vast—representing 15 percent of total U.S. forest land. Although these forests play a significant role in supplying natural resources to local Alaskan communities and in sustaining global energy, water, and carbon cycles, they were not inventoried as part of the FIA program until 2015, making them the last U.S. forest type to be formally inventoried. The reason: conducting intensive sampling across this expansive, remote landscape was a daunting and logistically complex endeavor.
But, a year earlier in 2014, the Pacific Northwest Research Station, in partnership with Alaska’s Department of Natural Resources, NASA, and the University of Alaska, demonstrated that it was possible—and feasible—to conduct a formal inventory of these “remaining fifteen percent”—at the same cost per acre as any other plot in the West. The team conducted a physical, ground-based inventory of one plot out of the five that they would sample in the rest of the West, per the national FIA sampling protocol, and then used state-of-the-art remote-sensing technology—obtained by high-resolution cameras and laser scanners affixed to aircraft—to collect detailed forest structure and condition information along swaths spanning the entire inventory unit. This integrated approach, which works especially well in the interior and reduced the overall cost per acre to inventory the interior, wouldn’t be as effective in other areas with mountainous territory and dense forest canopies. Now that the inventory is formally underway, this approach allows PNW-FIA to efficiently inventory Alaska’s remaining forested area at a research-plot grid density that is one-fifth the standard national FIA sampling design.
Members of the Pacific Northwest Forest Inventory and Analysis crew who conducted the pilot inventory of interior Alaska.
In 2016, the PNW-FIA team installed and inventoried 188 permanent plots in the Tanana Valley unit; this year, they plan to complete 230, and the remainder in 2018, before moving on to the Copper Susitna unit. This critical first step of installing plots and taking initial measurements in interior Alaska will take 12 years; when it is completed, the team will have inventoried 4,500 new forest inventory plots across the region. Then, they will move into the remeasurement phase, where the real gold mine of change information becomes accessible, returning to interior Alaska in future years for follow-up measurements and analyses that steadily add to our understanding of interior Alaska’s forests.
- by Yasmeen Sands, Public Affairs Specialist