Effects of Storage Temperatures and Duration on the Performance of Bareroot Deciduous Hardwood Trees

Abstract

Two-year-old Norway maple (Acerplatanoides), red oak (Quercus rubra), European mountain ash (Sorbus aucuparia), paper birch (Betula papyrifera), and Washington hawthorn (Crataegus phaenopyrum) seedlings were stored bare-root at temperatures of +4, 0 -2, and -4C for 0, 3, or 6 months. Survival and regrowth of plants stored at 0, -2, or -4C was better than at +4C. Survival, root regrowth, and % budbreak were maintained at pre-storage levels when Norway maple, red oak, European mountain ash, and paper birch were stored at -4C, and when Washington hawthorn was stored at -2C. Among the species tested, Norway maple and European mountain ash appeared most tolerant, red oak slightly less tolerant, and paper birch and Washington hawthorn the least tolerant of postharvest cold storage. Among Norway maple, red oak, and Washington hawthorn, tolerance to postharvest handling conditions appeared to be related to the depth of dormancy and a lower natural xylem water potential during the winter season. Increasing the length of time in storage reduced root regrowth and % budbreak, and increased plant mortality, stem dieback and the number of days to budbreak for most species stored at all test temperatures.