1. Partial asynchrony of coniferous forest carbon sources and sinks at the intra-annual time scaleRoberto Silvestro, Maurizio Mencuccini, Franco Biondi, Jesus Julio Camarero, Alberto Arzac, Filipe Campelo, Katarina Čufar, Henri E. Cuny, Martin De Luis, Annie Deslauriers, Jožica Gričar, Peter Prislan, 2024, izvirni znanstveni članek Povzetek: As major terrestrial carbon sinks, forests play an important role in mitigating climate change. The relationship between the seasonal uptake of carbon and its allocation to woody biomass remains poorly understood, leaving a significant gap in our capacity to predict carbon sequestration by forests. Here, we compare the intra-annual dynamics of carbon fluxes and wood formation across the Northern hemisphere, from carbon assimilation and the formation of non-structural carbon compounds to their incorporation in woody tissues. We show temporally coupled seasonal peaks of carbon assimilation (GPP) and wood cell differentiation, while the two processes are substantially decoupled during off-peak periods. Peaks of cambial activity occur substantially earlier compared to GPP, suggesting the buffer role of non-structural carbohydrates between the processes of carbon assimilation and allocation to wood. Our findings suggest that high-resolution seasonal data of ecosystem carbon fluxes, wood formation and the associated physiological processes may reduce uncertainties in carbon source-sink relationships at different spatial scales, from stand to ecosystem levels.
Ključne besede: carbon sinks, forests, conifers, intra-annual resolution
Objavljeno v DiRROS: 10.02.2025; Ogledov: 611; Prenosov: 461
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2. Low growth resilience to drought is related to future mortality risk in treesLucía De Soto, Maxime Cailleret, Frank Sterck, Steven Jansen, Koen Kramer, Elisabeth M.R. Robert, Tuomas Aakala, Mariano M. Amoroso, Christof Bigler, Jesus Julio Camarero, Katarina Čufar, Tom Levanič, 2020, izvirni znanstveni članek Povzetek: Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions might be crucial to long-term survival. We assess how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We find that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality. Resilience to drought is crucial for tree survival under climate change. Here, DeSoto et al. show that trees that died during drought were less resilient to previous dry events compared to surviving conspecifics, but the resilience strategies differ between angiosperms and gymnosperms.
Ključne besede: trees, mortality, gymnosperms, angiosperms, drought, resilience, resistance, recovery
Objavljeno v DiRROS: 20.02.2020; Ogledov: 2814; Prenosov: 1599
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