Title: Impacts of elevated atmospheric CO₂ and O₃ on Paper Birch (Betula papyrifera): reproductive fitness

Author: Darbah, Joseph N.T.; Kubiske, Mark E.; Nelson, Neil; Oksanen, Elina; Vaapavuori, Elina; Karnosky, David F.

Year: 2007

Publication: The Scientific World Journal. 7(S1): 240-246.

Abstract: Atmospheric CO₂ and tropospheric O₃ are rising in many regions of the world. Little is known about how these two commonly co-occurring gases will affect reproductive fitness of important forest tree species. Here, we report on the long-term effects of CO₂ and O₃ for paper birch seedlings exposed for nearly their entire life history at the Aspen FACE (Free Air Carbon Dioxide Enrichment) site in Rhinelander, WI. Elevated CO₂ increased both male and female flower production, while elevated O₃ increased female flower production compared to trees in control rings. Interestingly, very little flowering has yet occurred in combined treatment.