RT Journal Article SR Electronic T1 Irrigation Effects on the Growth of Newly Planted Oaks (Quercus Spp.) JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 83 OP 88 DO 10.48044/jauf.2005.010 VO 31 IS 2 A1 Laurence R. Costello A1 Katherine S. Jones A1 Douglas D. McCreary YR 2005 UL http://auf.isa-arbor.com/content/31/2/83.abstract AB The effect of irrigation on the growth of container-grown oaks was investigated over a 4-year period. Quercus lobata, Q. agrifolia, and Q. douglasii were irrigated at three levels of reference evapotranspiration (0, 0.25, and 0.5 ET0) after being established for 1 year at the University of California Bay Area Research and Extension Center in Santa Clara, California, U.S. Although no significant differences were found in trunk diameter growth for irrigation treatments after 4 years, growth of Q. agrifolia was significantly greater than Q. lobata and Q. douglasii. Root mass, shoot mass, and root distribution were measured for Q. agrifolia, and mean shoot:root ratio was found to be 2.6 to 1. Many roots of Q. agrifolia were found to develop with a stronger vertical than horizontal orientation, and root distribution was not significantly affected by irrigation treatments.