Biomass, Production, and Litterfall in the Coastal Sage Scrub of Southern California

A 22‐year‐old stand of coastal sage scrub in the coastal mountains of southern California had a peak standing aboveground biomass of 1,417 g/m 2 , determined by dimension analysis. Annual aboveground net primary production was 255 g/m 2 /yr, determined by monthly twig harvests of dominant species and the clipping production of subordinate species. The stand was codominated by two drought‐deciduous species, Salvia leucophylla and Artemisia californica , which together comprised 81% of the biomass. Annual litterfall was measured at 194 g/m 2 /yr. These biomass, production, and litterfall values are less than those measured in most evergreen chaparral communities in California. Seasonally, the two dominant shrubs began aboveground production in the winter soon after the first rains and continued growth for six months until early summer. A massive leaf fall occurred in May–June as the summer drought began, but twig and inflorescence production for both species continued at a high rate into the summer months. Salvia leucophylla had two shoot types: 1) an early spring canopy shoot that elongated rapidly, produced the inflorescence, and died in mid‐summer; and 2) a short side shoot produced in late spring with small dense leaves that were retained during the summer drought and early winter. Artemisia californica produced a single cohort of twigs in the early spring, most of which carried inflorescences by late summer.