During the AK-Land_2023_Alaska-Transect field campaign in June and July 2023, a comprehensive forest inventory was conducted across 21 full inventory plots and 71 additional short stops for genetic sampling in Alaska. The study area, located within the boreal forest biome and partially underlain by permafrost soils, was surveyed by scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and the University of Potsdam, Germany. The primary objectives were to document tree and forest characteristics to support research on treeline migration, stand infilling, natural disturbances, and succession processes, as well as to initialize and validate a forest model. Approximately 750 trees were inventoried within circular plots of 15 m radius, covering different vegetation types. Detailed measurements were recorded for around 10 individuals per tree species and 3 per shrub species. Tree parameters included species, position, height, crown base, diameter at the base (DBS), diameter at breast height (DBH), minimum and maximum crown diameter (DC min, DC max), and the presence of green cones. For shrubs, species, position, height, and minimum and maximum diameters were documented. Additionally, genetic samples were collected from 714 trees and shrubs in the form of needles, leaves, or cambium tissue, dried on silica gel, and stored at 4°C for future analysis.This dataset provides a valuable resource for studying boreal forest dynamics in the context of environmental change.