Tropospheric O(3) compromises net primary production in young stands of trembling aspen, paper birch and sugar maple in response to elevated atmospheric CO(2).

Concentrations of atmospheric CO(2) and tropospheric ozone (O(3)) are rising concurrently in the atmosphere, with potentially antagonistic effects on forest net primary production (NPP) and implications for terrestrial carbon sequestration. Using free-air CO(2) enrichment (FACE) technology, we exposed north-temperate forest communities to concentrations of CO(2) and O(3) predicted for the year 2050 for the first 7 yr of stand development. Site-specific allometric equations were applied to annual nondestructive growth measurements to estimate above- and below-ground biomass and NPP for each year of the experiment.

Research note: Can decreased transpiration limit plant nitrogen acquisition in elevated CO2?

N acquisition often lags behind accelerated C gain in plants exposed to CO2-enriched atmospheres. To help resolve the causes of this lag, we considered its possible link with stomatal closure, a common first-order response to elevated CO2 that can decrease transpiration. Specifically, we tested the hypothesis that declines in transpiration, and hence mass flow of soil solution, can decrease delivery of mobile N to the root and thereby limit plant N acquisition.

CO and light effects on deciduous trees: growth, foliar chemistry, and insect performance.

This study examined the effects of CO and light availability on sapling growth and foliar chemistry, and consequences for insect performance. Quaking aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh.

Photosynthetic responses of Miconia species to canopy openings in a lowland tropical rainforest.

We examined the photosynthetic acclimation of three tropical species of Miconia to canopy openings in a Costa Rican rainforest. The response of photosynthesis to canopy opening was very similar in Miconia affinis, M. gracilis, and M.