Management regimes affect woody plant productivity and water use efficiency in an urban desert ecosystem

Woody plant productivity and water use were evaluated under various management regimes in the Central Arizona Phoenix Long Term Ecological Research study area during 1999–2003. Management was defined as alteration of plant density, irrigation of plants, and removal of plant biomass via pruning. In a ground survey of 204 randomly chosen sites woody plant canopy area (CA) was higher in developed plots than in desert plots. Highest CA was measured in single family residential (SFR) sites but did not differ from most other developed site types. In experimental plots modeled after local SFR sites whole plot above ground biomass production (PP) and leaf area (LA) were higher and water use efficiency (WUE) was lower under high irrigation rate relative to low irrigation rate. Shrub pruning affected whole plot LA but not PP or WUE. Plant gas exchange data were used in conjunction with a trapezoidal integration model to predict maximum plant carbon uptake for plants in desert sites or under various irrigation regimes. These data might be used to facilitate long term monitoring of plant productivity and water use in the study area and to establish sound management practices in urban and suburban environments.