Methods for measuring arctic and alpine shrub growth: a review

Shrubshave increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundraecosystems. The analysis of shrubgrowth is improving our understanding of tundravegetation dynamics and environmental changes. However, dendrochronologicalmethods developed for trees, need to be adapted for the morphology and growth eccentricity of shrubs. Here, we review current and developing methods to measure radial and axial growth, estimate age, and assess growth dynamics in relation to environmental variables. Recent advances in sampling methods, analysis and applications have improved our ability to investigate growth and recruitment dynamics of shrubs. However, to extrapolate findings to the biomescale, future dendroecological work will require improved approaches that better address variation in growth within parts of the plant, among individuals within populations and between species.