Forest Floor Characteristics within a Small Plot in Douglas‐Fir in Western Washington

Abstract

AbstractThe forest floor of a 0.04‐ha plot beneath a 40‐year‐old Pseudotsuga menziesii (Mirb.) Franco plantation was intensively sampled. Means and their standard errors, the range of values and the number of samples required to estimate the mean within 10% with 95% confidence were determined for forest floor dry weight, water storage, calcium, magnesium, sodium, potassium, manganese, nitrogen, ash content, weight loss on ignition and also pH and conductivity of equilibrium solutions from the forest floor and A and B horizons of the soil. Dry weight of the forest floor is 14,300 ± 440 kg/ha and water storage is 2.78 mm or 208% while nutrient contents expressed in kg/ha arc: calcium, 123.27 ± 4.85; magnesium, 19.45 ± 1.14; potassium, 27.31 ± 1.07; manganese, 14.87 ± 0.67; nitrogen, 140.14 ± 6.08, and weight loss on ignition 11,211 ± 228 kg/ha. Dry weight correlates with ash weight, loss on ignition and water storage while ash content correlates with magnesium. Conductivity and pH of equilibrium solutions did not compare with values previously obtained using tension lysimeter installations suggesting that equilibrium with the exchange complex is not achieved during soil moisture flow. Means of most properties are estimated within 10% with less than 30 samples.