This dataset comprises centimetre-resolution orthomosaics generated from structure-from-motion (SfM) processing of UAV-based multispectral imagery acquired with a MicaSense Altum sensor. The study region spans parts of the northern boreal forest and the tundra–taiga ecotone (TTE). The primary objective is to map vegetation cover, with a focus on differentiating forest types. Fieldwork was designed and conducted by researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), during peak summer 2022 (10 July to 19 August). The study area encompasses a broad bioclimatic gradient, extending from tundra and open forest near Inuvik, Northwest Territories, Canada, across the southern Yukon and mountainous terrain of the Mackenzie and Cassiar Mountains, to regions near Fort Nelson, British Columbia, Canada. Survey locations were pre-selected using satellite data. At each site, transects of at least 50 m width and 500 m length were surveyed. Ground reference data were collected from one or, in rare cases, multiple circular plots with a diameter of 30 m. UAV flights were conducted at an altitude of 70 m above ground level and a speed of 5 m/s, following manufacturer recommendations. Raw imagery was processed in Agisoft Metashape. After image alignment and radiometric calibration using a reflectance panel, orthomosaics were exported at the highest available spatial resolution.

Each file contains the following 7 bands: - Blue, 475 nm, 32 nm bandwidth- Green, 560 nm, 27 nm bandwidth- Red, 668 nm, 14 nm bandwidth- Red edge, 717 nm, 12 nm bandwidth- NIR, 842 nm, 57 nm bandwidth- LWIR, 11 µm, 6 µm nm bandwidthAlpha mask/transparency, value 0 means no data, value 65535 means valid dataFunding and AcknolwledgmentsThis work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project number 563037533. It received funding from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, for the expedition CA-Land_2022_NWCanada Forest Change Northwest Canada. We also acknowledge funding for our equipment by the project Potsdamer InnoLab für Arktisforschung no. F221-08-AWI/001/002 from the Brandenburg Ministry for Science, Research and Culture (MWFK). We would like to thank the logistics department of the Alfred Wegener Institute, especially Volkmar Aßmann and Jan Kahl, for their support in realising the fieldwork. During the preparation phase, contacts with several First Nations people in the areas of our planned field work, Canadian agencies and institutes were very helpful. We are particularly grateful to Katherine Wolfenden, Land and Resources Coordinator in Fort Nelson, Christina Martin, Lands & Resources Coordinator for the Gwich'in Tribal Council, and Laura Nerysoo, Teslin Tlingit Renewable Resource Council Coordinator, as well as Andrew Koe, our wildlife monitor from the Gwich'in First Nation, for helping to ensure our safety during our fieldwork in bear country.