Forests of the Tanana Valley State Forest and Tetlin National Wildlife Refuge, Alaska: results of the 2014 pilot inventory

Abstract

This report highlights key findings from a test (“pilot”) of an interior Alaska forest inventory design. The pilot inventoried the forests of the Tanana Valley State Forest (TVSF) and the Tetlin National Wildlife Refuge (TNWR) in the Tanana River Valley of interior Alaska, covering 2.5 million ac. The inventory consisted of a systematic grid of 98 field-measured plots integrated with NASA’s Goddard- LiDAR/Hyperspectral/Thermal (G-LiHT) imaging system. We summarize and interpret basic resource information such as forest area, ownership, volume, carbon stocks in trees, ground layers, dead wood, and soils; and vegetation community structure and composition. The black spruce forest type covered 49 percent of the forested area. Most of the aboveground live tree biomass was found in Alaska birch and black spruce forest types, but white spruce forest types had the highest mean aboveground live tree biomass per acre. Standing dead tree biomass was 8 percent of the amount in the live tree pool, with the greatest amounts in the white spruce forest type. Soil carbon per acre in the measured layers was highest in black spruce forests and lowest in aspen forests. Biomass of ground layers (i.e., moss and lichen mats) was almost twice as high on black spruce forests than on other forest types. Shrub and grass cover were comparable among units, but forb cover was greater on TVSF than on TNWR. The design and protocols tested during this pilot were refined for the implementation of the large-scale inventory of forests of interior Alaska that started in 2016.