Production patterns of understory layers in several Galician (NW Spain) woodlands - Seasonality, net productivity and renewal rates

Production and quantity, as well as the renewal rates of understory vegetation biomass, were measured in shrublands and oak, conifer, and eucalyptus forest stands. A significant (P<0.05) negative correlation was found between understory biomass and tree canopy cover. However, stand tree density and basal area were not significantly correlated with understory. Herbs were the major contributors to seasonal fluctuation in production. Although productivity differed among stands, the seasonal pattern of production did not. Production was higher in the warmer seasons for all sites. This higher productivity was correlated with plant species richness. The renewal rates of the understory biomass were dependent on the herbaceous/woody plant ratio. Different responses were found in productivity of shrubs, forbs, ferns, and grasses after cutting understory biomass. These dissimilarities were also conditioned to forest type. (C) 1998 Elsevier Science B.V.