Understanding nutrient dynamics of young postfire forests may yield important insights about how stands develop following stand-replacing wildfires. We studied 15-year-old lodgepole pine stands that regenerated naturally following the 1988 Yellowstone fires to address two questions: (1) How do foliar nitrogen (N) concentration and total foliar N vary with lodgepole pine density and aboveground net primary production? (2) Is foliar N related to litter production and to rates of gross production, consumption, and net production of soil NH4+ and NO3-? Foliar N concentration of new lodgepole pine needles averaged 1.38%; only stands at very high density (>80 000 trees-ha-1) approached moderate N limitation. Foliar N concentration in composite (all-age) needles averaged 1.08%, varied among stands (0.87%-1.39%), and declined with increasing tree density. The foliar N pool averaged 48.3 kg N-ha-1, varied among stands (3.6-218.4 kg N-ha-1), and increased with aboveground net primary production. Total foliar N was not related to laboratory estimates of net production of NH4+ or NO3- in soils. Lodgepole pine foliage is a strong N sink, and N does not appear to be limiting at this early successional state. The initial spatial patterns of postfire tree density strongly influence landscape patterns of N storage.
All Science Journal Classification (ASJC) codes
- Global and Planetary Change