Relationships Among Humus Forms, Forest Floor Nutrient Properties, and Understory Vegetation

Washington D.C.

1990

S. 564-581

2 Abb., 8 Tab., zahlr. Lit. Ang.

Bandaufführung

7380

64601

Morphologically characterized humus forms and their associated understory vegetation have been used to infer different modes of decomposition of forest floor materials, but few studies have analyzed relationships among humus forms, forest floor nutrient properties, and understory vegetation. Examination of these relationships was accomplished in this study by a numerical analysis of forest floor and vegetation data that were obtained from 151 cool mesothermal forest ecosystems of southern British Columbia and stratified into seven humus form groups. Four forest floor nutrient properties (pH, C/N-ratio, total N, and sum of exchangeable Ca, Mg, and K) and nine diagnostic combinations of species differentiated the groups. pH and mineralizable-N consistently increased, and C/N ratio consistently decreased from Lignomors to Hemimors, Humimors, Mormoders, Leptomoders, and to Vermimulls, indicating the presence of a regional decomposition gradient. Multivariate summaries of the nutrient properties and diagnostic species were highly correlated. A consistent correlation was also found between the nutrient properties and indicator plants of nitrogen-rich soils.