We investigated growth, water relations, and water use of bare root (BR) and balled-burlapped (BB) Patmore green ash following transplanting into an irrigated landscape setting in a high desert climate. Treatments were green ash harvested as larger (40 mm caliper) BB and BR trees, and smaller BR stock (25 mm caliper). During establishment, we measured canopy growth for 3 years, and for 2 years plant water relations [predawn water potential and midday stomatal conductance (gS)] and water depletion within the root zone. All treatments expressed varying degrees of isohydric responses to root loss by reducing gS that maintained water potential nearly constant, but least so for the smaller BR trees. gS was greater than that of all larger trees, meaning that for the same cost in water potential as the larger trees, BR-Small benefitted from more open stomates and presumably greater carbon gain. Greater initial conductance apparently translated into more growth. Year 1, BR-Small trees had the least total leaf area, but by Year 3 total leaf area was not different among all treatments. Also during Year 1, the ratio of water use to local reference evapotranspiration [plant factor (PF)] was 0.36 for large BR trees vs. 0.56 for BB trees, similar to the recommended PF of 0.5 for trees in dry climates. These results suggest smaller BR trees are a cheaper alternative for high desert landscapes while reaching nearly equivalent growth to BB trees after 3 years. Achieving high growth of BR trees would need careful scheduling of irrigation amount and frequency based on leaf area, root zone size, and local reference evapotranspiration.
We thank the Utah Agricultural Experiment Station for financial support (Utah Agricultural Experiment Station paper 8935).
ASABE2015Determining landscape plant water demands. American Society Agricultural and Biological Engineers Standard S623. 1 Nov. 2015. <http://elibrary.asabe.org/abstract.asp?search=1&JID=2&AID=46518&Abstract=S623.htm>.
AthertonJ.M.NicholC.J.MencucciniM.SimpsonK.2013The utility of optical remote sensing for characterizing changes in the photosynthetic efficiency of Norway maple saplings following transplantationIntl. J. Remote Sens.34655667
DagitR.DownerA.J.2002To prune or not to prune: Responses of coast live oaks (Quercus agrifolia) to canopy retention during transplanting p. 369–380. Gen. Tech. Rpt. Pacific Southwest Research Station USDA Forest Service (PSW-GTR-184)
DostalekJ.WeberM.MatulaS.FrantikT.2009Planting of different-sized tree transplants on arable soilCent. Eur. J. Biol.4574584