Vertical gradient of needle ozone uptake within the canopy of Cryptomeria japonica.

Leaf ozone uptake through the stomata is an important index for the ozone risk assessments on trees. Stomatal conductance (g) and ozone concentration ([O]), determinants of the leaf ozone uptake, are known to show vertical gradients within a tree canopy. However, less is known about the within-canopy vertical gradient of leaf ozone uptake.