Long-Term Trends in Tree-Ring Width and Isotope Signatures [δ¹³C, δ¹⁵N] of Fagus sylvatica L. on Soils with Contrasting Water Supply

• Published in: Ecosystems (New York) Vol. 16; no. 8; pp. 1413 - 1428
• Main Authors: Härdtle, Werner, Niemeyer, Thomas, Assmann, Thorsten, Baiboks, Saskia, Fichtner, Andreas, Friedrich, Uta, Lang, Anne C., Neuwirth, Burkhard, Pfister, Laurent, Ries, Christian, Schuldt, Andreas, Simon, Natalie, von Oheimb, Goddert
• Format: Journal Article
• Language: English
• Published: Boston Springer Science+Business Media 01.12.2013; Springer US; Springer; Springer Nature B.V
• Subjects: Analysis; Biomedical and Life Sciences; Climate change; Climate models; Dendroclimatology; Drought; Ecology; Ecotypes; Environmental Management; Forest soils; Forest stands; Geoecology/Natural Processes; Growth rings; Hydrology/Water Resources; Isotopes; Life Sciences; Plant growth; Plant populations; Plant Sciences; Signatures; Soil sciences; Soils; Stable isotopes; Terrestrial ecosystems; Trees; Water supply; Zoology; drought limitation; Luxembourg; nitrogen deposition; basal area increment; dendrochemistry; dendroecology; climate change
• ISSN: 1432-9840; 1435-0629
• DOI: 10.1007/s10021-013-9692-x

We investigated long-term responses (since 1850) of Fagus sylvatica (Luxembourg; central Europe) to shifts in temperature, precipitation, and nitrogen deposition by analyzing diameter at breast height (DBH) increment, basal area increment (BAI), and tree-ring stable isotopes (δ¹³C, δ¹⁵N). We compared stands on soils with contrasting water supply (Regosols and Cambisols with an available water capacity of ca. 40 and 170 mm, respectively) and of two different age classes (ca. 60 vs. 200 years). All stands showed a peak in DBH increment in the decade 1978-1987, but a decline in increment growth in subsequent decades. In addition, BAI declined in mature stands in the last two decades. Decreasing increment rates were attributable to an increasing drought limitation of stands, mainly induced by increasing temperatures in the last two decades. Contrary to our expectations, stands on Cambisols showed a similar susceptibility to shifts in temperature and precipitation as stands on Regosols, suggesting a strong adaptation of the respective ecotypes grown at dryer sites. This result was in line with long-term trends for tree-ring δ¹³C signatures, which did not differ significantly between stands on Cambisols and Regosols. Climate impacts on tree-ring δ¹⁵N signatures were low. High spring precipitation and temperatures caused increasing and decreasing δ¹⁵N values, respectively, but only in mature stands on Cambisols. Stands on Regosols tended to have lower δ¹⁵N values than stands on Cambisols. Decreasing δ¹⁵N values in recent decades suggest an increasing impact of allochthonous N loads with isotopically lighter N.