Binkley, Dan; Cromack, Kermit Jr.; Fredriksen, Richard L. 1982. Nitrogen accretion and availability in some snowbrush ecosystems. Forest Science. 28(4): 720-724.
ABSTRACT. We examined two chronosequences in the Oregon Cascade Mountains to assessnitrogen accretion and availability in relation to snowbrush (Ceanothus •elutinus Dougl.). In two12-year-old snowbrush ecosystems, total soil nitrogen to 30-cm depth exceeded levels in adjacentold-growth stands by 500 and 570 kg has-'. Inclusion of the approximate nitrogen content ofaboveground snowbrush and forest floor biomass raised the estimate of nitrogen fixation to 94to 100 kg ha-' yr-' over 12 years. Snowbrush also increased the availability index of soil nitrogen.but nitrogen availability appeared high in all ecosystems. We speculate that nitrogen fixation bysnowbrush during early succession in these ecosystems has been sufficient to prevent nitrogenlimitation throughout the entire successional sequence. The presence of snowbrush for 12 yearsalso increased soil carbon 40 and 60 percent in the two chronosequences. FOREST Sci. 28:720-724.
ADDITIONAL KEY WORDS. Ceanothus rehainus, nitrogen fixation, forest soil fertility, carbon.