title: Effects of decadal exposure to interacting elevated CO2 and/or O3 on paper birch (Betula papyrifera) reproduction.
abstract: We studied the effects of long-term exposure (nine years) of birch (Betula papyrifera) trees to elevated CO(2) and/or O(3) on reproduction and seedling development at the Aspen FACE (Free-Air Carbon Dioxide Enrichment) site in Rhinelander, WI. We found that elevated CO(2) increased both the number of trees that flowered and the quantity of flowers (260% increase in male flower production), increased seed weight, germination rate, and seedling vigor. Elevated O(3) also increased flowering but decreased seed weight and germination rate. In the combination treatment (elevated CO(2)+O(3)) seed weight is decreased (20% reduction) while germination rate was unaffected. The evidence from this study indicates that elevated CO(2) may have a largely positive impact on forest tree reproduction and regeneration while elevated O(3) will likely have a negative impact.
authors: Michigan Technological University, School of Forest Resources and Environmental Sciences, Houghton, MI 49931, USA. jndarbah@mtu.edu
authors: Joseph N T
authors: JN
authors: Darbah
authors: Mark E
authors: ME
authors: Kubiske
authors: Neil
authors: N
authors: Nelson
authors: Elina
authors: E
authors: Oksanen
authors: Elina
authors: E
authors: Vapaavuori
authors: David F
authors: DF
authors: Karnosky
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D029662:Betula / Q000187:drug effects / Q000502:physiology*; D018533:Biomass; D002245:Carbon Dioxide / Q000633:toxicity*; D004784:Environmental Monitoring / Q000379:methods; D035263:Flowering Tops / Q000187:drug effects / Q000254:growth & development; D016468:Forestry; D018525:Germination; D017752:Greenhouse Effect; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D012098:Reproduction; D036226:Seedlings; D012639:Seeds; D013995:Time; D014922:Wisconsin
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D002245:Carbon Dioxide; D010126:Ozone