Evaluation of planting sites common to a southeast Alaska clear-cut. I. Nutrient status
Nutrient status was evaluated in the upper 15 cm of three microsite types (rotten wood, exposed mineral soil, and undisturbed duff) common in old-growth western hemlock – Sitka spruce (Tsugaheterophylla (Raf.) Sarg.) – (Piceasitchensis (Bong.) Carr.) clear-cuts. Rotten wood had significantly wider C:N ratio (>100:1) than either undisturbed duff (36:1) or exposed mineral soil (31:1), indicating lower nitrogen availability in rotten wood. Higher levels of inorganic [Formula: see text] in <2 mm fraction of rotten wood compared with the 2- to 9.4-mm fraction indicate that N availability increases as decay advances. Available P was low and could be a major factor limiting growth in all microsites. Exchangeable Mg was relatively low (0.0025 mg/cm3) in exposed mineral soil. Microsite nutrient expression on a volumetric rather than a gravimetric basis better represents availability of nutrients to planted seedlings.