Growth Responses of Tree Roots to Atmospheric CO2 Enrichment
Smith, A.R., Lukac, M., Bambrick, M., Miglietta, F. and Godbold, D.L. 2013. Tree species diversity interacts with elevated CO2 to induce a greater root system response. Global Change Biology 19: 217-228.
In describing their findings, the five researchers report that at the end of the final growing season, "the overall effect of the elevated CO2 treatment was a 31% increase in fine root biomass," but they say that "in the polyculture fine root biomass was enhanced by 68% under elevated CO2." Smith et al. thus conclude their work by stating that their data suggest that "existing biogeochemical cycling models parameterized with data from species grown in monoculture may be underestimating the belowground response to global change." Indeed, the CO2-induced enhancement of tree root growth out in the real world of nature may actually be much larger than previously believed.
Jackson, R.B., Mooney, H.A. and Schulze, E.D. 1997. A global budget for fine root biomass, surface area, and nutrient contents. Proceedings of the National Academy of Sciences USA 94: 7362-7366.