Physiology, morphology, and ozone uptake of leaves of black cherry seedlings, saplings, and canopy trees

air pollution arbre forestier canopy couvert cubierta de copas damage estoma fenologia feuille fisiologia vegetal foliage forest trees gas exchange hojas intercambio de gases leaf conductance leaves ozone ozono pennsylvania pennsylvanie phenology plant anatomy plant physiology plant water relations plantule potentiel hydrique prunus serotina relaciones planta agua relation plante eau seedlings stomata stomate transpiration water potential xilema xylem