Mineral Nutrition in Sierra Nevada Mixed Conifer: Wildfire Effects, Species Distinctions, and Temporal Variation

An investigation of wildfire effects on mineral nutrition of Jeffrey pine (Pinus jeffreyi Grev. & Balf.) along with species comparisons of the nutrition of unburned specimens of this pine to those of unburned California white fir (Abies concolor var. lowiana [Gord.] Lemm.) were conducted in an eastern Sierran mixed conifer stand. Foliar Fe and Mn concentrations were frequently higher and Al was consistently so in burned than in the unburned pine as assessed in six sampling periods distributed over more than two postfire growing seasons while base cation/metallic element molar ratios consisting of Ca/Al, K/Al, K/Mn, Ca/Fe, Mg/Fe, K/Fe, and Ca/Zn were often lower in the former. Foliar N, P, Fe, Zn, and Cu were frequently higher in unburned pine than unburned fir while the reverse proved true concerning K, Ca, Mn, B, and Al; and likewise several molar ratios involving Al and Mn were higher in the former while several involving Fe, Zn, and Cu were higher in the latter. At midstudy, mineral soil in the burned stand portion had lower K but higher S, Mn, and Zn than that in the unburned portion, and the former had several molar ratios that were lower as well.