Alaska’s vast size and geographic diversity make quantifying its natural resources challenging. The state encompasses a landmass so vast it holds the largest share of the nation’s total forest land, setting it apart from the lower 48 states. This immense scale, combined with extreme northern ecosystems, necessitates specialized inventory methods to accurately estimate the extent of its tree population. Understanding the number of trees requires appreciating the unique methods and ecological distinctions involved in the tally.
Quantifying Alaska’s Forest Cover
The total forested acreage in Alaska is estimated at approximately 129 million acres, representing the enormous scale of its woodlands. This figure covers land with at least a ten percent canopy cover of trees, a definition used by the U.S. Forest Service’s Forest Inventory and Analysis (FIA) program. These resource figures are derived from a continuous process combining satellite imagery with data collected from a systematic network of fixed-radius ground plots.
The total number of trees is consequently a massive figure, currently calculated in the billions. For the highly dense coastal temperate rainforest region alone, the count for live trees with a diameter of one inch or greater stands at over 6.5 billion stems. However, a precise, single total for the entire state remains an estimate because the vast Interior region’s inventory is still in progress and presents logistical difficulties. The FIA program must also differentiate between total forest land and “timberland,” which is forested ground capable of producing commercial timber, with the latter being a significantly smaller portion of the whole.
The ongoing inventory for the 114 million-acre boreal forest unit is a major undertaking that will refine the total tree count as field plots are completed.
Defining Alaskan Tree Species and Distribution
Alaska’s forests are divided into two distinct geographic zones, each supporting different tree species dictated by climate and terrain. The coastal zone, which includes Southeast and parts of Southcentral Alaska, is characterized by a temperate rainforest environment. This zone is a dense, high-biomass ecosystem dominated by towering Western Hemlock and Sitka Spruce.
The remaining, much larger portion of the state is covered by the Interior’s boreal forest, or taiga, an ecosystem that stretches across 114 million acres. Here, the cold, dry climate favors species adapted to short growing seasons and fire-driven succession cycles. The principal trees in the taiga are the hardy Black Spruce, White Spruce, Paper Birch, Aspen, and Balsam Poplar.
The coastal forest, though much smaller in area, boasts a significantly higher volume of wood per acre, with Western Hemlock and Sitka Spruce accounting for the majority of the sawtimber volume. Conversely, the boreal forest is characterized by lower density and smaller, slower-growing trees. This distinction in density and size is a key factor in how the total number of trees is calculated and valued across the state.
The Unique Ecology of Alaskan Forests
Environmental extremes shape Alaska’s forests in ways that directly complicate the inventory process and the final tree count. At the highest latitudes and elevations, the Arctic Treeline marks the boundary where conditions prevent upright tree growth. This zone features Krummholz, a German term meaning “twisted wood,” which describes stunted, shrub-like evergreens that are small for their age.
These dwarf trees, though centuries old, often do not meet the minimum height or diameter requirements to be counted in standard forest inventories, effectively lowering the official tree population. The presence of continuous and discontinuous permafrost further influences forest structure across a vast portion of the Interior. Perennially frozen ground restricts the depth of the active layer, which is the surface soil that thaws each summer.
This shallow thaw layer forces species like Black Spruce to develop root systems that are extensive but shallow, limiting their growth and overall density. The permafrost and associated peatlands in Alaskan forests are also a substantial global carbon reservoir, containing an estimated 53 percent of the nation’s total carbon stock, with over 91 percent of that stored in the soil. As the climate warms, the thaw of this frozen organic material releases carbon dioxide and methane, illustrating the complex ecological role of this unique forest landscape.