Forest Floors in Douglas‐Fir Forests: I. Dry Weight and Chemical Properties

Abstract

AbstractVarious types of understory plant communities occur in association with Douglas‐fir (Pseudotsuga menziesii [Mirb] Franco) forest in western Oregon. Dry weight and chemical properties were determined for 9 forest floor types from the Oregon Coast Range.Dry weight of forest floors varied considerably within stands. Between‐stands values ranged from 20,000 to 76,000 lb/acre. Volatile matter ranged from 69 to 86%. Ranges in values for other factors were: pH, 4.0–6.0; available P, 36–146 ppm; exchangeable K, 1.5–5.4 meq/100g; Ca, 6.5–23.5 meq/100g; Mg, 5–12.8 meq/100g; CEC, 54–76 meq/100g; total N, 0.71–1.52%; total P, 0.089–0.211%; total K, 0.115–0.323%; total Ca, 0.325–1.05%; total Mg, 0.157–0.334%; and total S, 0.081–0.163%. The types having the lowest content of metallic cations were from areas of high precipitation and soils with low base saturation. There was no apparent relationship between levels of exchangeable cations and percentage of these elements in the forest floor.