Methodology:

Sample collection of Alnus alnobetula and Salix spp. was undertaken in the Inuvialuit Settlement region during field campaigns in 2022, 2023, and 2024. The Inuvialuit Settlement Region is one of the four regions of Inuit Nunangat, and part of the Northwest Territories, Canada. Data collection was undertaken within the wider Beavers and Socio-ecological Resilience in Inuit Nunangat (BARIN) project collaborative environment - which adhered to CARE principles including contributing to advancing Inuit governance in research according to the National Inuit Strategy on Research priority areas. Collaboration with Indigenous experts underpinned the project including Inuit co-development and management of the project, and direct consultation with and co-investigation by the Fisheries Joint Management Committee and Joint Secretariat organisations. Relevant work permits were obtained for work on Inuvialuit private lands, as well as approval from local Hunters and Trappers Committees (HTCs) where updates were provided regularly at HTC board meetings. Via work with community researchers, knowledge was also regularly informally shared and informed the research process. Key project datasets are shared amongst all project partners and stored in ways that allow access and joint control for academic and Inuvialuit partners.

Shrub stems were sampled from both living erect canopy-forming shrubs and from beaver-browsed stems along the Inuvik-Tuktoyaktuk Highway (ITH), including some sites at Trail Valley Creek (TVC). Collected shrubs were then subsampled into discs, and further split into subsamples of sufficient size for microslides. Subsamples were soaked in water for at least 24 hours prior to cutting of transverse sections with a GSL1-microtome to thickness of 10-20 micrometers. After sectioning, slides were then bleached, rinsed with milliQ water and double-stained with a 4:1 Safranin-Astrablue mixture. Sections were then rinsed sequentially with 50, 75 and 99% ethanol, before permanently fixing with Canada balsam under a cover slip, drying and stabilising in an oven at 60°C for a minimum of 12 hours. The samples are used for dendrochronological chronology formation and crossdating.

Data quality:

There is some variation in notation and ID system used between years due to multiple sample collectors, processors, and data managers. An additional sample ID has been retrospectively added in order to allow for a standardised ID across all years and all relevant BARIN project datasets.