Forward Modeling Reveals Multidecadal Trends in Cambial Kinetics and Phenology at Treeline

• DOI: 10.3389/fpls.2021.613643
• Publication Date: 2021-01-28T04:38:41Z
• Authors: Jan Tumajer; Jakub Kašpar; Hana Kuželová; Vladimir V. Shishov; Ivan I. Tychkov; Margarita I. Popkova; Eugene A. Vaganov; Václav Treml
• Keywords: Growing season; Tracheid; Annual growth %

Significant alterations of cambial activity might be expected due to climate warming, leading growing season extension and higher growth rates especially in cold-limited forests. However, assessment climate-change-driven trends intra-annual wood formation suffers from the lack direct observations with a timespan exceeding few years. We used Vaganov-Shashkin process-based model to: (i) simulate daily resolved numbers differentiating cells; (ii) develop chronologies onset termination specific phases phenology during 1961–2017. also determined dominant climatic factor limiting for each day. To asses validity, we 8 years xylogenesis monitoring treeline region Krkonoše Mts. (Czechia). The exhibits high validity case spring phenological seasonal dynamics tracheid production, but its precision declines estimates autumn duration. simulations reveal an increasing trend number tracheids produced by cambium year 0.42 cells/year. Spring (onset cell enlargement) show significant shifts toward earlier occurrence (for 0.28–0.34 days/year). In addition, there is increase simulated entire associated redistribution controls over activity. Results suggest that at are driven temperature-stimulated intensification kinetics, decoupling summer effect low temperature frequency climatically optimal days. Our results highlight kinetics stimulation temperatures shifting determine recent ecosystems. Redistribution individual factors controlling questions temporal stability signal cold forest under ongoing change.