Forest resources of the Tanana unit, Alaska: 2018

Abstract

This report provides detailed estimates and highlights key findings from Forest Inventory and Analysis (FIA) data collected across the Tanana unit in interior Alaska, 2014–2018. The Tanana unit encompasses much of the Tanana River basin and is one of six inventory units distributed throughout the expansive boreal forest that comprises much of Alaska. Estimates of forest area, volume, aboveground biomass, and ecosystem carbon are provided across land ownerships, forest types, and forest demographics throughout the unit. The Tanana unit covers approximately 33.4 million ac, of which 20.8 million ac (62 percent) were considered forest land managed mostly by state and local governments. Private landowners and state and local governments oversee most of the live-tree volume on timberland, where much of the region’s forest management occurs. A majority of the unit, 10.8 million ac (52 percent), is composed of black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) forests, while Alaska paper birch (Betula neoalaskana Sarg.) and white spruce (Picea glauca (Moench) Voss) forests comprised about 3.9 million ac (19 percent) and 3.4 million ac (16 percent), respectively. Unique to this inventory was the incorporation of soil carbon estimates, which comprised 76 to 90 percent of total ecosystem carbon pools among forest types. More than half of the total soil carbon was found in black spruce forests where cool, saturated soils limit organic matter decomposition. Understory vascular vegetation was primarily comprised of low-stature shrubs: lingonberry (Vaccinium vitis-idaea L.), bog Labrador tea (Ledum groenlandicum), bog blueberry (Vaccinium uliginosum), and resin birch (Betula glandulosa)—species frequently encountered in the most common forest type, black spruce. Resin birch, bog blueberry, and marsh Labrador tea (Ledum palustre ssp. decumbens) were the most common vascular plant species on nonforest plots. Ground layer biomass was dominated by nitrogen-fixing feather mosses in uplands and Sphagnum peat mosses in lowlands. This report summarizes the main outcomes of a detailed survey of forest and nonforest conditions throughout a region that has previously lacked a comprehensive inventory at such a scale, despite its global and regional importance.Supplemental Download - Forest resources of the Tanana unit, Alaska: 2018.https://www.fs.usda.gov/pnw/pubs/pnw_gtr1005-supplement.pdf