Annual ring growth of a widespread high-arctic shrub reflects past fluctuations in community-level plant biomass

1. Long time-series of primary production are rarely available, restricting our mechanistic understanding of vegetation and ecosystem dynamics under climate change. Dendrochronological tools are increasingly used instead, particularly in the Arctic – the world’s most rapidly warming biome. Yet, high-latitude plant species are subject to strong energy allocation trade-offs, and whether annual allocations to secondary growth (e.g. ‘tree-rings’) actually reflects primary production above-ground remains unknown. Taking advantage of a unique ground-based monitoring time-series of annual vascular plant biomass in high Arctic Svalbard (78N), we evaluated how well retrospective ring growth of the widespread dwarf shrub Salix polaris represents above-ground biomass production of vascular plants.
2. Using a balanced design in permanent plots for plant biomass monitoring, we collected 30 S. polaris shrubs across five sites in each of two habitats. We established annual ring growth time-series usi...