direction can temporarily heat other areas as well. The warmer climate in cities is associated with the following: A shorter none growing season (time between first and last frost) and less severe frosts A reduction in the number of frost days (to nearly half the normal amount and snow days. This warmer climate has the following effects on the vegetation in cities: a longer growing season (e.g., in Vienna, by about 10 to 20 days yearly) a shift in phenological phases. Urban areas of central Europe are experiencing a retreat of native species and archaeophytes. Ate the same time they are and will continue to be centers of introduction and have an abundance of newcomers. The origin of those new species is primarily the warmer regions of Europe, Asia and the Americas. There must be a few questions here that one must look at. One of those would be: is this all really such a band thing? Could we not make use of such climatic advantages and, for instance, use roofs and other spaces within towns and cities where to grow vegetables that could do with a longer growing season or simply in order to supply the demand by people for local foods. Certainly there are ways of utilizing cities too for a variety of purpose of growing foods and this is being done already in some places. We just need more of that. There are enough unused spaces, including roofs, that could be utilized. While there then would be