The influence of soluble carbohydrates, slow-release nitrogen and a plant growth regulator on transplant survival of trees

Abstract

High mortality rates following planting out of ornamental trees into urban landscapes is a common phenomenon within the UK. Previous research has shown that the quantity of reserve carbohydrates in root tissue is crucial for successful survival following transplanting from the nursery into field conditions. Enhancing the root carbohydrate status of ornamental trees during nursery management has received little attention. Supplementing 45 l containerised stock of Lombardy Poplar (Populus nigra “Italica” (Moench) Koehne), English oak (Quercus robur L.) and European beech (Fagus sylvatica L.) with a high nitrogen slow-release fertiliser, sucrose and a plant growth regulator during nursery production significantly enhanced root carbohydrate (glucose, fructose, sucrose, total sugar) content of all three tree species. Based on total root sugar enhancement, efficacy of treatment was in the order paclobutrazol>nitrogen fertiliser ≥ ≤ sucrose. Significantly enhanced root carbohydrate content during nursery production may have contributed to reduced transplant mortality and enhanced field performance (growth and vitality) of all three tree species over the following 2-year period. However, the magnitude of treatment response varied between each tree species. Results of the study strongly indicate that enhancing root carbohydrate content in the nursery prior to out-planting can increase transplant survival and subsequent field performance over a 2-year period.