Nitrogen Deposition Boosts U.S. Tree Growth
Thomas, R.Q., Canham, C.D., Weathers, K.C. and Goodale, C.L. 2010. Increased tree carbon storage in response to nitrogen deposition in the US. Nature Geoscience 3: 13-17.
Based on their analysis, it was determined that "nitrogen deposition (which ranged from 3 to 11 kg ha-1 yr-1) enhanced the growth of eleven species and decreased the growth of three species," while it "enhanced [the] growth of all tree species with arbuscular mycorrhizal fungi associations," leading to "a 40% enhancement over pre-industrial conditions," which response "includes the direct effects of nitrogen deposition on tree growth through soil fertilization, foliar nitrogen uptake and other potential interactions between nitrogen deposition and other environmental changes, including CO2 fertilization." And to give some feeling for the significance of the size of this response, they say that it "exceeds the 23% enhancement of net primary production anticipated for the year 2050 from a doubling of atmospheric CO2 over preindustrial levels, as estimated using free-air CO2 enrichment studies," citing in this regard the work of Norby et al. (2005).
Thomas et al. conclude that "nitrogen deposition is an important mechanism contributing to carbon sequestration within these temperate forests," but they say that this phenomenon is still "unlikely to explain all of the observed terrestrial carbon sink." Nevertheless, it does go a long way towards doing so, while demonstrating the major benefits of the concomitant increases in the air's CO2 content and temperature with which it interacted over the course of the industrial revolution and its aftermath, which latter increases the IPCC opines are two of the worst things ever to have happened to the biosphere. Clearly, however, they were not. And neither was the increase in anthropogenic nitrogen deposition. All three of these phenomena interacted with each other in such a way as to greatly increase the productivity of these forests.
Norby, R.J., DeLucia, E.H., Gielen, B., Calfapietra, C., Giardina, C.P., King, S.J., Ledford, J., McCarthy, H.R., Moore, D.J.P., Ceulemans, R., De Angelis, P., Finzi, A.C., Karnosky, D.F., Kubiske, M.E., Lukac, M., Pregitzer, K.S., Scarasci-Mugnozza, G.E., Schlesinger, W.H. and Oren, R. 2005. Forest response to elevated CO2 is conserved across a broad range of productivity. Proceedings of the National Academy of Sciences 102: 18,052-18,056.