Nutrient Relations of the Evergreen Shrub, Adenostoma fasciculatum, in the California Chaparral

Seasonal changes in biomass, nitrogen, and phosphorus contents in plant parts of the evergreen shrub, Adenostoma fasciculatum, indicate that the shoot of this plant takes up nutrients during the winter rainy season prior to any above-ground growth. Such a nutrient uptake pattern would result in a possible conservation of nutrients that would otherwise be lost to the plant through decomposition and leaching from the litter during the rainy season that follows the long summer drought. A similar uptake pattern has been noted in shrubs of the Australian mediterranean-climate region. We propose that evergreen leaves are efficient in providing a high photosynthetic return per unit of nutrient invested and also provide a sink for nutrients taken up from the soil during nongrowth periods. Primary production as well as nutrient pool sizes and fluxes of Adenostoma are similar to those found in scrub communities of other mediterraneanclimatic regions.