Contrasting tree ring Hg records in two conifer species: Multi-site evidence of species-specific radial translocation effects in Scots pine versus European larch

0549942 - GLÚ 2022 RIV NL eng J - Journal Article
Nováková, Tereza - Navrátil, Tomáš - Demers, J. J. - Roll, Michal - Rohovec, Jan
Contrasting tree ring Hg records in two conifer species: Multi-site evidence of species-specific radial translocation effects in Scots pine versus European larch.
Science of the Total Environment. Roč. 762, March (2021), č. článku 144022. ISSN 0048-9697. E-ISSN 1879-1026
R&D Projects: GA ČR(CZ) GA20-06728S
Institutional support: RVO:67985831
Keywords : Tree rings * European larch * Larix decidua * Pinus sylvestris * Mercury * Atmospheric Hg * Biogeochemical archives * Heartwood * Sapwood
OECD category: Environmental sciences (social aspects to be 5.7)
Impact factor: 10.754, year: 2021
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0048969720375537?via%3Dihub

Tree ring records are increasingly being used as a geochemical archive of past atmospheric mercury (Hg) pollution. However, it is not clear whether all tree species can be used reliably for this purpose. We compared tree-ring Hg records of two coniferous species - widely used Scots pine (Pinus sylvestris) and less frequently used European larch (Larix decidua) at 6 study sites across the Czech Republic. Site-specific mean Hg concentrations in tree-ring segments of larch ranged from 2.1 to 5.2 μg kg−1, whereas pine had higher mean Hg concentrations (3.6–8.3 μg kg⁻¹). Temporal records of Hg concentrations in tree rings of larch and pine differed significantly. Comparisons with previously documented peat Hg records showed that larch tree-ring Hg records more closely agreed with peat archive records. For pines, which had a large, tree-age dependent number of sapwood rings (62 ± 17, 1SD), we found a strong relationship between the year of peak Hg and the number of sapwood tree rings (p = 0.012, r² = 0.35), as well as between peak Hg year and the sapwood-heartwood boundary year (p < 0.001, r² = 0.65), rather than with temporal changes in atmospheric Hg levels. The much greater number of pine sapwood tree rings appears to promote radial Hg translocation, resulting in the shift of Hg peaks backward in time through the tree-ring record. In contrast, Larch consistently had a low number of sapwood tree rings (19 ± 6, 1SD), and more closely agreed with peat Hg records. This study suggests that European larch, a tree species characterized by a relatively low and consistent number of sapwood tree rings, records changes in atmospheric Hg concentrations more reliably than does Scots pine, a species with a relatively high and variable number of sapwood tree rings.
Permanent Link: http://hdl.handle.net/11104/0325837