Distribution and Chemical Characteristics of Cations in Annual Rings of Japanese Cedar

Abstract

The objectives of this study were to investigate the distribution and chemical characteristics of cations in annual rings of Japanese cedar (Cryptomeriajaponica D. Don) grown in a healthy stand of an unindustrialized region in Japan and discuss the possibility of using cations in tree-rings as a chronological index of acidic deposition. Radial distributions of some cations and P at different vertical positions of the stem were analyzed for five trees from the same mountain. Each cation and P in all trees showed a specific distribution in its radial pattern but similar distribution trends were observed at all vertical positions. The cations and P were classified into three groups: (I) constant radial concentrations (Ca 2 + , Sr 2 +, Na ÷ , and probably Ba 2 +), (II) high concentrations in the heartwood and low in the sapwood (Mg +, K + , Rb ÷ , Cs +), and (IH) increasing concentrations in sapwood (P, Mn z ÷, Cũ +). The total concentration of cations exceeded the calcium-binding capacity (CBC) of the wood, and the excess was attributed to K + in a salt form. The CBC increased from the sapwood/ heartwood boundary toward the pith in the heartwood but remained constant in the sapwood. The increase of CBC in the heartwood was consistent with the profile of Mg 2+ , indicating a transfer of Mg + into heartwood and fixation on the acquired binding site. The radial distribution of 9°Sr was closely related to the cumulative deposition of fallout from the nuclear weapon tests, but that of ~TCs was unrelated. This suggests immobility of Sr~ + and mobility of Cs ÷ in the horizontal direction of wood. The conservation of the historical ~eSr/Sr2 + change indicated that no influence of heartwood formation on the chemical environment of Sr~+ in cedar xylem and a possibility of using Sr + as a chronological index of nutrient availability. A steady-state in nutrient availability is speculated for trees growing in this mountain because all of the trees analyzed show constant radial distributions of Sr 2 + for decades.

Radial variations in wood mineral element concentrations: a comparison of beech and pedunculate oak from the Belgian Ardennes

“…They ascribed those changes to the long-term effects of leaching of forest soil by acid rain, in line with similar previous reports in other polluted regions of the world [4,5,20,22,24]. In the present study, there was a systematic, statistically significant decrease of Ca, Mg, K, P and Mn in oak heartwood, but there was no significant change in Al and N concentrations and in Al/Ca ratio.…”

“…A similar pattern found in two coexisting species with contrasting wood structure could arguably point to a common environmental effect. However, as stated hereabove, decreasing cations concentrations from pith to outer heartwood (or to cambium) have been commonly observed in many different species of trees in various environmental contexts [24,25,27,29,31], including beech [15] and several oak species [6,31]. Therefore, it is questionable whether such outwardly decreasing concentration gradients are actually indicative of cation depletion in the soil solution.…”

“…The size of the sample is in the range of recent dendrochemical investigations (e.g. [6,11,15,16,22,24,26]). …”

“…Although nutrient concentration profiles are highly species-and element-specific [6,24,27,29], it appears that N, P, K and S most often have higher concentrations in the sapwood, in line with their metabolic role in living cells and their high mobility in xylem [9,12,27,34]. By contrast, Ca, Mg and Mn often have higher concentrations in the heartwood [27].…”

“…The "wavy" profile of Mg and K in beech, accompanied by relatively large standard deviations might indicate that such radial movements are occurring. Another explanation can lie in a systematic decrease of wood cation binding capacity (CBC) with ageing as shown by Momoshima et al in Japanese cedar [24]. CBC has apparently never been assessed in oak and beech wood.…”