Paul Eric Aspholm
Research Scientist
(+47) 932 20 452
paul.eric.aspholm@nibio.no
Place
Svanhovd
Visiting address
Svanhovd, NO-9925 Svanvik
Abstract
Blue rings (BRs) are wood anatomy anomalies that present great potential in identifying cold spells during the growing season. In this study, we investigated the effect of temperature anomalies on the occurrence of two types of BR in Pinus sylvestris at its northern distribution limit in Norway. Of the 3508 individual tree rings from 1727 to 2022 analysed, we identified 206 BRs from a span of 85 years, the oldest formed in 1730. We distinguished two types of BR: Type A with normal earlywood and latewood ending with a thin blue layer; and Type B with the entire latewood zone replaced by earlywood-like tracheids. Our results demonstrate that the two types have a common climatic trigger – a cool spring and autumn. However, Type A is more linked to tree-ring width, whereas Type B is associated more closely with tree ontogeny and local environmental constraints. Although we observed the formation of BRs even in old trees, we found that they formed more frequently in young specimens. We showed that while the short-term cyclical drivers of Type A remained persistent, the climatic or environmental drivers associated with Type B gradually diminished under climate change. Our study demonstrates that the differentiation of BRs into types can contribute to a better understanding of their driving factors; however, detailed intra-annual phenological and xylogenetic monitoring will be crucial to achieve further insights.
Abstract
Foredrag under Arendalsuka
Abstract
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