Effects of Atmospheric Nitrogen Deposition on High Elevation Colorado Forests
2004. Effects of Atmospheric Nitrogen Deposition on High Elevation Colorado Forests. Pages 10-14. In HIGH ALTITUDE REVEGETATION WORKSHOP NO. 16.. Colorado State University, Fort Collins, Colorado. March 3-5, 2004. Colorado Water Resources Research Institute. Colorado State University. Information Series No. XX
Atmospheric nitrogen deposition from energy, automobile, and agricultural emissions acts as a fertilizer to these forests, but this fertilization also alters natural ecosystem processes. The authors compared old-growth forest characteristics from the east side of the Colorado Front Range, where nitrogen deposition ranges 3-6 kg N/ha/yr, to characteristics from the west side, and where nitrogen deposition is several times lower. Fertilization experiments were also conducted on east- and west-side forest stands. Higher nitrogen deposition has led to greater nitrogen accumulation in needles, greater soil microbial activity, and accumulation of N in soil floors. Fertilization of east-side forests caused microbial activity and nitrogen leaching to increase, since these forests are close to nitrogen saturation. Fertilization of west-side forests increased organic and foliar nitrogen concentrations. Understory vegetation differs across the east- and west-side plots, with east-side vegetation being much more diverse than west-side.