Evaluation of planting sites common to a southeast Alaska clear-cut. IV. Nutrient levels in ectomycorrhizal Sitka spruce seedlings

Abstract

Sitka spruce (Piceasitchensis (Bong.) Carr.) seedlings colonized by the ectomycorrhizal fungi Laccarialaccata (Scop. ex Fr.) Berk and Br., Hebelomacrustuliniforme (Bull, ex St. Amans) Quel., or Cenococcumgeophilum Fr. and a noninoculated control were planted on rotten wood, undisturbed duff, undisturbed duff on the north side of large stumps, and exposed mineral soil in an area recently clear-cut on Chichagof Island, southeast Alaska. Uptake and concentrations of N, P, K, Ca, Mg, and several micronutrients in foliage, stems, and roots were determined 2 years after outplanting. There were no significant interactions between fungal treatments and microsite types for uptake or concentration of any nutrient. Uptake and concentrations of N and P in foliage and roots did not differ significantly among fungal treatments. Foliar K and Cu concentrations were significantly higher in control seedlings than in those with L. laccata ectomycorrhizae. Calcium was the only nutrient analyzed that was present in higher concentrations in seedlings inoculated with H. crustuliniforme than in controls. Concentrations of foliar P, Mn, and Zn were significantly greater in seedlings grown on undisturbed duff (protected north side) than in seedlings grown on exposed mineral soil. However, foliar concentrations of all nutrients tested were not significantly different between seedlings grown on undisturbed duff (unprotected sites) and those grown on mineral soil. Seedlings grown on rotten wood had significantly greater concentrations of foliar Ca than seedlings grown on either exposed mineral soil or undisturbed duff. The on-site colonization of control seedlings after outplanting indicates that resident ectomycorrhizal fungi readily establish and appear to provide equal if not improved nutrient benefits compared to inoculated seedlings. Greater nutritional benefits were derived by planting on certain microsite types (duff and protected duff) than by inoculating with specific ectomycorrhizal fungi.