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Highlights: [•] We use EDXRF to identify trends in high-resolution cation distribution in tree rings. [•] Potassium counts are elevated in sapwood and infected wood. [•] Localized peaks in calcium counts can be associated with crystals in wood. [•] Intra-annual variation in peak counts appears associated with ring boundaries. [ABSTRACT FROM AUTHOR]

Logs of eastern red cedar, Juniperus virginiana L., with well-developed bands of light-colored wood (“included sapwood”) within heartwood can be unsuitable for sawn wood products. This finding is in contrast to published information that the “included sapwood” is (1) a heartwood anomaly rather than sapwood and (2) its occurrence is not a reason to exclude this type of wood from commercial use. The alternative view presented here is that “included sapwood” is wound-initiated discolored wood which is the starting point for wood decay in living trees and which has adversely altered wood properties before the development of decay symptoms. Our study of the patterns of discoloration and decay, electrical resistance properties, elemental analysis, wood acidity, solubility in dilute NaOH, total phenol content, and tests of wood decay resistance indicated that the so-called included sapwood was discolored wood. This light-colored discolored wood had no greater decay resistance than sapwood, a common finding in other tree species in which “included sapwood” is found. Half the sample disks sent to our laboratory had symptomatic decay within the bands of light-colored discolored wood bounded by a phenol-enriched protective layer on the bark side and phenol-enriched heartwood on the pith side of the band. This ring-rot, even in its pre-symptomatic stage, can cause problems during processing for sawn wood products. Therefore, logs with well-developed bands of light-colored discolored wood should be considered high-risk material for some products, although they could be useful for others. [ABSTRACT FROM AUTHOR]

Abstract: Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of environmental change due to acidic deposition or forest management practices. We compared the effects of Ca fertilization treatment on Ca concentration in wood and Ca and oxalate (Ox) concentration in foliage at two locations with different initial concentrations of Ca in the soil. We found greater amounts of Ca in wood from the high-Ca location than from the low-Ca location. Ca concentration was greater in wood formed in the 1970s than for wood formed in the 1980s, the outermost decadal band in these samples. The Ca-treatment was detected as an increased concentration of Ca in the 1970s and 1980s decadal bands. We also found that variation in Ca and Ox in foliage was essentially stoichiometric. The appearance and response to chemical tests of crystals in foliage were consistent with identification as calcium oxalate. The increased Ca in wood after Ca-treatment of the soil supports the use of dendrochemistry of base cations to investigate environmental change. However, differences in Ca concentration between the two outermost decadal bands of wood illustrate that internal processes of translocation and storage also affect Ca concentration. Calcium oxalate production in foliage diverts carbon from ordinary biosynthesis and energy-yielding processes. This sequestration, shedding, and decomposition of foliage may represent a significant and under-recognized contribution to carbon and Ca cycling. [Copyright &y& Elsevier]

The decay of coarse woody debris is a key component in the formation of forest soil and in the biogeochemical cycles of Ca and Mg. We tracked changes in density and concentration of Ca and Mg in sapwood of red maple (Acer rubrum L.), red spruce (Picea rubens Sarg.), paper birch (Betula papyrifera Marsh.), and eastern hemlock (Tsuga canadensis (L.) Carr.) in Maine and New Hampshire. We repeatedly sampled 10 logs of each combination of tree species and location at the time of felling and at 2-year intervals for 6 years (birch and hemlock) or 8 years (spruce and maple). We found that density loss was essentially linear for the time period investigated, with birch and maple sapwood decaying at faster rates than spruce and hemlock. Repeated-measures analysis and regression modeling of log-transformed concentrations indicated a significant accumulation of Ca for sapwood of all tree species at both locations (30%–90% increase after 6–8 years of ground contact). Regression estimates of Mg concentration in spruce and maple declined about 20% during the 8 years of ground contact. There was no significant trend for Mg concentration in birch and hemlock. Variation in decay rates and trends in Ca and Mg concentration may be due to differences in sapwood quality, the community of wood decay fungi and associated organisms, or to abiotic conditions. [ABSTRACT FROM AUTHOR]

Arsenic concentrations were measured in annual rings, pith, bark, and leaves of five tree species (four genera) from a site highly contaminated with As in Vineland, New Jersey, and two nearby uncontaminated areas. The highest As concentrations were found in bark (0. 68±0. 89 mg/kg, n =16) and leaves (1. 9±1. 8 mg/kg, n =4) from the contaminated area. Tree-ring As levels from the contaminated area (0. 28±0. 15 mg/kg, n =32) were low but still considerably higher than those from the control areas (0. 06±0. 06 mg/kg, n =30). There is a generally positive relationship between soil and tree-ring As levels. The overall low uptake of As by trees contrasts with that of P, a chemical analog for As(V) in aerated soils. Much higher P concentration in sapwood than in heartwood indicates that P is exported into more recently formed wood during the conversion from sapwood to heartwood; this again is drastically different than the behavior of As which is present in sapwood and heartwood at comparable levels. Variable sapwood As concentrations observed in detailed radial profiles of tree-ring chemistry of a pine and an oak from the contaminated site suggest that As is most likely transported among multiple rings within the sapwood. Therefore, tree species for which sapwood is thin (e.g., oak as in this study) should be preferred for reconstructing the history of contamination of a site. Due to the possibility of lateral translocation between growth rings, further studies are necessary to understand within-tree As transport and storage before dendrochemistry can be confidently accepted for such applications. [Copyright &y& Elsevier]