The effects of irrigation and mulching on growth and physiology of some shade tree species

In the present scenario, we focus on the need for environmentally friendly establishment and low cost management methods of the urban green areas. Compost and its skilled use as mulching material and also to improve organic matter content in the soils, can contribute to such a development. However, the use of compost may not be beneficial, unless the quality is good and the methodology of its use is based on a high level of knowledge in the arboricultural business. Also, the need for efficient water use is emphasised, both by politicians and the general public, especially in Southern Europe. The business of the urban greening sector must take such problems into consideration when deciding upon the choices of methods in plant production, establishment and management. When choosing methodology in urban forestry and urban greening, there may be interactions between the different factors considered, so that when one factor is altered or introduced, other factors need to be modified as well. The project is focused on the use of cultivation techniques (i.e. mulching with pine bark, mulching with green compost and control where herbicide has been used to control weeds), and their possible influence on growth and physiology of some shade tree species widely grown in the urban environment. In 2004 an experimental field was planted at the Fondazione Minoprio (Como). Trees have been planted following the randomised block design with 3 blocks and four plants per block. The treatment are mulching with pine bark, mulching with green compost, herbicide. a) plant height at the beginning and at the end of the season b) bud-break date c) shoot elongation d) leaf gas exchange e) chlorophyll fluorescence Preliminary results have shown that the cultivation techniques applied in this project can have remarkable effects on tree physiology, but results can be variable according to the species. Compost was the most effective on Tilia x europaea, compared to pine bark and control, while on Aesculus x carnea, control with pine bark showed the lowest leaf gas exchange and no differences where found between compost and pine bark. Shoot elongation was higher in the composted linden trees, while no differences emerged in horsechestnut. Plant height and trunk diameter were affected only in Aesculus, with compost showing the best results compared to the other thesis. No differences where found regarding bud break date in 2006. Chlorophyll fluorescence was affected by the different treatment especially in the second part of the season when compost and pine bark showed higher values compared to control.