Plant species composition, calculated leaf masses

Green plants confer numerous physical and aestheticbenefits in urban environments. Plants sequestercarbon dioxide and release oxygen, and surfaces allowdeposition of pollutants.

Vegetation in the Phoenix, Arizona, metropolitan area was surveyed using a modi®ed strati®ed random sampling design to

identify plant species and to measure foliar volumes for species-speci®c calculation of leaf mass. We identi®ed the genus and

species and measured the crown dimensions of plants located in a park and parking lot, and in three types of urban landscapes:

¯ood-irrigated, mesic and xeric. Species compositions of these landscape types were compared quantitatively using a

Sorenson index of similarity and the landscape types were found to be dissimilar. The three landscape types varied in

calculated leaf masses and the respective identities of the dominant species, and relatively few plant species accounted for the

majority of the leaf mass. Plant species and leaf mass data were used to estimate relative contributions from each landscape

type of the biogenic volatile organic compounds isoprene and monoterpenes. Results from this study have implications for

future plant surveys taken for biogenic emissions inventory development, and for plant species selection for urban landscapes,

especially large-scale tree planting programs.