Table 3.

Effect of commercial parking lot planting location (landscape median and perimeter) and time of year (April and August 2002) on leaf carbon assimilation (A), stomatal conductance (gs), internal leaf to ambient CO2 concentrations (Ci/Ca), and leaf chlorophyll concentration (Chl) of four landscape tree species in Phoenix, Arizona.

Tree species/Parking lot locationA (mol/m2/s)gs μmol/m2/s)Ci/CaChl (mg/g)
Australian bottle tree
Median6.0z by5.7 b82.1 b64.7 a0.60 a0.55 a5.6 a4.0 b
Perimeter9.5 a6.2 a112.5 a59.5 a0.58 a0.50 a5.1 b4.3 a
Arizona ash
Median9.2 a7.4 b117.0 b178.0 b0.58 a0.76 a4.2 b4.3 b
Perimeter11.6 a12.2 a156.9 a241.6 a0.58 a0.70 b4.6 a4.7 a
Argentine mesquite
Median7.9 a5.3 a73.6 a85.6 a0.46 a0.67 a3.6 b4.5 a
Perimeter8.2 a6.5 a75.9 a103.6 a0.47 a0.66 a5.4 a4.7 a
Chinese elm
Median6.7 a8.6 b121.2 b110.0 a0.66 b0.57 a3.6 b4.0 b
Perimeter7.1 a10.9 a110.2 a123.9 b0.69 a0.54 b4.2 a5.0 a
  • z Values are treatment means. For gas exchange variables; n = 24. For chlorophyll concentration, n = 168, except for Argentine mesquite, n = 10.

  • y Treatment means followed by the same letter within columns by tree species are not significantly different, Fisher’s LSD test, α = 0.05.