Soil and stand characteristics and elemental concentration of tall shrub twigs.

Woody twigs (= or <3 mm diam) of tall shrubs were collected during winter in 18 forest stands in the Superior National Forest of NE Minnesota. The stands ranged from young Pinus resinosa plantations to natural pine and hardwood stands to lowland conifer stands on organic soils. Levels of most elements in twigs were not significantly related to soil properties. Twigs from stands on organic soils were higher in Mg and Zn concentration than were twigs from the stands on mineral soils, and Ca was lower in twigs on soils with coarser texture. Although significant differences were found in elemental concentrations of Ca, Mg, Zn, Fe and Mn among stands classified by vegetation type, these differences were small among the upland stands. Stand age did not appear to have a major influence on elemental concentration, but twigs in younger stands had higher K and lower Fe concentrations than did twigs in older stands. Two consistent trends emerged from the analysis, those of differences in Ca and Zn associated with vegetation and soil, and of differences in K associated with stand development. -Authors