Can Elevated CO2 Enhance Woody-Plant Seedling Establishment in Treeless Grasslands?
Reference Davis, M.A., Reich, P.B., Knoll, M.J.B., Dooley, L., Hundtoft, M. and Attleson, I. 2007. Elevated atmospheric CO2: a nurse plant substitute for oak seedlings establishing in old fields. Global Change Biology 13: 2308-2316. Background The authors introduce their most interesting study by stating that “woody vegetation is encroaching into grasslands throughout many regions of the world,” and they note that explanations for this phenomenon have included, among other things, “elevated levels of atmospheric CO2 (Idso, 1992; Polley et al., 2003).” Hence, they decided to test the CO2 hypothesis at the Cedar Creek Natural History Area in east-central Minnesota, where they report that “water limitation represents a significant obstacle to the establishment of oaks in the site’s old fields.” What was done In May of 1999, four oak (Quercus ellipsoidalis) acorns were planted in each of 24 plots in each of six experimental FACE rings, three of which were maintained at an elevated atmosphe
