Radial distributions of Cd in stems of oak trees (Quercus robur L.) re-analyzed after 10 years

Abstract

Radial distribution patterns of Cd were determined in stems of the same oak trees (Quercus robur L.) in 1983 and again in 1994. On both sampling dates the same distribution patterns were generally observed. Highest concentrations of Cd were found at the sapwood-heartwood transition. A sharp drop over this boundary towards inner parts of the stems occurred in all trees. In the decade between the two investigations the sapwood-heartwood boundaries had shifted outwards by 9-11 annual rings. The Cd peaks at the boundaries were shifted by approximately the same interval. The results suggest that the described Cd peaks are mobile in a radial direction. The present location of such peaks cannot be used to infer the pollution history of the tree's environment. The Cd accumulation at the sapwood-heartwood boundary is probably affected by physiological processes in the wood. Thus it is concluded that radial distributions of Cd in stems of oak trees are no reliable source of information for retrospective monitoring of past time pollution levels.

A Comparison of Tree Rings and Peat Deposit Geochemical Archives in the Vicinity of a Lead Smelter

“…Considering the presence of Pb and Cd in highly soluble compounds, their ionic charge radius ratio and their non-essentiality for plants, a limited radial mobility in xylem of these two elements is supposed (Cutter and Guyette 1993). However, in oak trees (Quercus robur), a radial movement of Cd, expressed as a concentration peak shift, was detected in segments between sapwood and heartwood towards the tree bark (Hagemayer 1995). Maxima in Pb concentrations in tree cores after 1990 (Fig.…”

Changes in Mercury Deposition in a Mining and Smelting Region as Recorded in Tree Rings

“…), though the use of dendrochemical techniques has had varying success (e.g. Eklund 1995;Hagemeyer 1995;Watmough and Hutchinson 2002). Factors influencing the applicability of dendrochemical analyses include differences in: (1) tree species and physiology (in particular physiological differences between sapwood and hardwood), (2) the metal of concern, (3) deposition levels and (4) soil chemistry (Cutter and Guyette 1993;Watmough 1999).…”

Heavy Metals in Polish Forest Stands of Quercus Robur and Q. Petraea

“…It is noteworthy that Hagemeyer and Breckle (1986) and Hagemeyer (1995) observed an increased accumulation of Cd at the transition zone between sapwood and heartwood of oak trees, i.e. in the growth rings formed about 5-10 years before sampling.…”

“…Many reports attest to the possible correlation between industrialization and motorization, associated with air pollution, and the level of heavy metals in corresponding growth rings (Ault et al, 1970;Ward et al, 1974;Rolfe, 1974;Kardell and Larsson, 1978;Queirolo et al, 1990). Other authors point to the possibility of radial movement of metals towards heartwood, which contradicts a strong relationship between concentration of heavy metals in successive growth rings and environmental pollution at that time (Hagemeyer and Breckle, 1986;Hagemeyer, 1995;Hagemeyer and Shin, 1995;Balk and Hagemeyer, 1994;Brackhage et al, 1996;Lukaszewski et al, 1988Lukaszewski et al, , 1993Nabais et al, 1999;). It was found that xylem has ion-exchanging properties, as Ca 2+ ions exclude Pb 2+ and Cu 2+ ions from xylem.…”