Responses of communities of tropical tree species to elevated CO 2 in a forest clearing

Abstract

Communities of ten species of tropical forest tree seedlings from three successional classes were grown at ambient and elevated CO 2 in large open-top chambers on the edge of a forest in Panama . Communities grew from 20 cm to approximately 2 m in height in 6 months. No enhancements in plant biomass accumulation occurred under elevated CO 2 either in the whole communities or in growth of individual species. Reductions in leaf area index under elevated CO 2 were observed, as were decreases in leaf nitrogen concentrations and increases in the C:N ratio of leaf tissue. Species tended to respond individualistically to elevated CO 2 , but some generalizations of how successional groupings responded could be made. Early and mid-successional species generally showed greater responses to elevated CO 2 than late-successional species, particularly with respect to increases in photosynthetic rates and leaf starch concentrations, and reductions in leaf area ratio. Late-successional species showed greater increases in C:N ratios in response to elevated CO 2 than did other species. Our results indicate that there may not be an increase in the growth of regenerating tropical forest under elevated CO 2 , but that there could be changes in soil nutrient availability because of reductions in leaf tissue quality, particularly in late-successional species.

Two tropical conifers show strong growth and water-use efficiency responses to altered CO2concentration

“…There was no positive response to increasing c a in either of the two angiosperm species. The lack of a growth response of Tabebuia and Chrysophyllum to c a is consistent with previous experiments in which seedlings of tropical tree species were grown in unfertilized soil (Lovelock et al, 1998;Winter et al, 2000;Cernusak et al, 2011). The causes of differential responses of plants to elevated c a in greenhouse experiments have recently been revisited by Ali et al (2013).…”

Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition

“…Lovelock et al (1998) grew assemblages of 10 tropical forest tree species at ambient and doubled CO 2 in open-top chambers at a forest edge in Panama. During the six months of the experiment, the plants grew from ca.…”

Growth of a poplar short rotation coppice under elevated atmospheric CO2 concentrations (EUROFACE) depends on fertilization and species

“…Studies on LAI in elevated CO 2 concentrations yielded a variety of results: increased [25,29,38], as well as decreased [14,23] or unchanged [15,18] LAI's were reported in different studies on the effect of elevated CO 2 on trees.…”