Joseph N T Darbah

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Paper birch (Betula papyrifera Marsh.) and three trembling aspen clones (Populus tremuloides Michx.) were studied to determine if alterations in carbon gain in response to an elevated concentration of CO(2) ([CO(2)]) or O(3) ([O(3)]) or a combination of both affected bud size and carbohydrate composition in autumn, and early leaf development in the(More)
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%(More)
In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: We report of no evidence of photosynthetic and stomatal acclimation in aspen trees(More)
The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO(2) and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO(2) protected photosynthesis of both species against moderate heat stress. Elevated CO(2) increased carboxylation(More)
We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees,(More)
Introduction The concentration of CO2 in the atmosphere has risen by approximately 35% since the pre-industrial era to approximately 380 ppm, now, and is continuing to rise by 1-2 ppm per year. This rate of CO2 increase in the atmosphere is unprecedented in the recent past, for at least two million years. Despite the thousands of papers that have been(More)
Now living in southern Illinois on his family's old farmstead with his wife Carol, Richard was one of the original set of principal investigators who conceived and developed the Aspen FACE project. Richard had a wonderful eye for detail and spent days looking over the shoulders of our contractors during the construction of Aspen FACE, finding and correcting(More)
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