What was done
Upper-canopy leaves of four species of trees located in a semi-deciduous tropical forest near Panama City, Republic of Panama, were enclosed in small transparent cups enriched with CO2 to about twice the current ambient concentration and sampled to determine the effects of elevated CO2 on sugar and starch production.

What was learned
"Against expectation," elevated CO2 caused 30 and 100% increases in leaf sugar and starch concentrations, respectively, for all four tropical tree species studied, regardless of whether they were sampled in the morning or evening or under high or low light intensities.  This observation demonstrates that atmospheric CO2 enrichment significantly stimulates individual leaf total nonstructural carbohydrate contents in tropical tree species, even when there is a very large "sink" (the rest of the tree) to which the carbohydrates could readily be exported.

What it means
As the CO2 content of the air continues to rise, it will likely stimulate total nonstructural carbohydrate production in nearly all vegetation, including tropical trees.  These additional carbohydrates can be used in many beneficial ways, including those that would increase the further growth and development of the vegetation.