text: LaDeau and Clark determined that "carbon dioxide enrichment affected mean cone production both through early maturation and increased fecundity," so that "trees in the elevated CO 2 plots produced twice as many cones between 1998 and 2004 as trees in the ambient plots." They also report finding that trees grown in elevated CO 2 "made the transition to reproductive maturation at smaller diameters," and that they "not only reached reproductive maturation at smaller diameters, but also at younger ages." By 2004, for example, they say that "roughly 50% of ambient trees and 75% of fumigated trees produced cones." In addition, they observed that "22% of the trees in high CO 2 produced between 40 and 100 cones during the study, compared with only 9% of ambient trees." What it means