Effect of root-stimulating treatments on physiologic and growth performances of Platanus x acerifolia and Ulmus pumila seedlings

2014 | Dr. Manuela Baietto, University of Milan, Italy

Chemical industries annually release several new natural and synthetic fertilizer products to help urban trees survive the stresses associated with transplanting. In fact, a 5% failure rate for new transplants within the first five years is common, and in many cases, it may exceed 25% with the surviving plants not often exhibiting good growth rates. Many authors report the primary determining factor in the transplanting success in the urban environment is a prompt response of the root system to water and nutrient uptake. It is well known that a correct provision of nutrients during the initial growing phases helps to maximize the fitness of seedlings by facilitating the development of a strong root system that can overcome post-transplanting stresses. Several papers on the fertilization of landscape trees give conflicting results, particularly pertaining to the wide range of eco-physiological needs and growth factor requirements of the wide diversity of species.

Our project is aimed at testing the effects of some commercially-available products (biostimulants), considered alternatives to traditional fertilizers, applied under different watering regimes, in order to produce plants that are fit for transplanting into the urban environment because they are capable of achieving high growth performances in the short and long term. Experiments will be conducted on two species (London Plane and Siberian Elm), traditionally and frequently used as shading trees in Northern and Central Europe. This is a research area that has not been studied previously – assessing the nutrient factors most responsible for the transplanting success of these species.

Study Results

About 5% plants in the urban environment die within the first year after transplanting. During particularly hot summers, mortality can reach as high as 20-25%. They also show a very low aesthetic and environmental contribution. Causes of mortality are bad planting sites, non-compliant management practices, poor uptake of water or nutrients, low soil fertility, vandalism, bad choice of species and poor quality of transplanting materials. In particular, transplanting failures are due to the young root system, not properly prepared to adapt and survive in a new site condition. The final goal of this project is evaluating the effects of two fertilizing products (biostimulants), on physiologic performances and growth rate on young trees belonging to two shading tree species, that may help reduce the incidence of new planting failures in the urban environment during the first few years after transplanting.

At the end of the second year the following general results were obtained. Both biostimulants (fulvic acid: FA and seaweed extract: SE) promoted a more uniform growth, compared to the check (water only). The application of both the biostimulants promoted a superior growth, although it was not always statistically significant. One application per year is to be considered generally enough, to get positive results in term of better and more uniform growth. In terms of dry matter, the same conclusions could be drawn, although in Platanus x acerifolia two application per year of the SE were required in order to equate the result of one application of FA.

The project would not have been possible without TREE Fund funding, given the particular situation both in Italy and in the EU as well. The general policy put in place since many year is to favour by large the ‘basic’ approaches in the field of science, so there are very little chances to find calls for applied research. In addition, landscaping and ornamental plants are basically neglected in term of R&D, despite the growing concern on the liveability of our urban environments.

Year: 2014

Funding Duration: 1-3 years

Grant Program: Jack Kimmel International Grant

Grant Title: Effect of root-stimulating treatments on physiologic and growth performances of Platanus x acerifolia and Ulmus pumila seedlings

Researcher: Manuela Baietto

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For more information on this project, contact the researcher via TREE Fund at treefund@treefund.org.