A műemlékek sokszínűsége (A 28. Egri Nyári Egyetem előadásai 1998 Eger, 1998)

Előadások / Presentations - PÁRKÁNY Ildikó: Gardens of mansions

where tree roots have enough room under the wide pavements. The provision for ecological requirements has resulted in a very nice stock of trees along busy roads, too. Flower compositions make the spectacle colourful in smaller parks. Various baskets and holders planted with flowers are clever solutions. VALUE DEFINITION OF PLANTS The first question is to see why there is a need to define the value of plants. In countries with advanced environmental culture it is natural, that communities need ornamenting and environment improving plants. To cultivate and care for these plants is a continuous task, and it is a good idea if the population appreciate them. The cultivation and care of green areas was done in a way that had been unchanged for years in our country. Sufficient financial resources were usually available provided by the councils. The change of system has, however, modified a lot. Many a time the finances do not stretch to cultivating the green areas properly once the compulsory tasks had been financed by the local authorities. Local authorities often struggle with the lack of financial resources by obtaining the necessary means wherever it is possible while areas covered with valuable plants fall victim. It happens that the population damage the plants and traditional measures fine these people up to a few thousand forints. Value definition attempts to change all this in the hope that by defining the real value of plants they will be appreciated in the proper way. When working out the method we regarded the assimilating foliage as the most valuable part of plants with respect to urban life therefore chose it as the basis of evaluation. We also wanted to have a realistic value. These are indicated by two factors: 1 The assimilating surfaces and their products participating in the formation of the environment are known or can be learnt and measured by figures. 2 Trees as components of green surfaces can be evaluated with difficulty since their products are changeable depending on their age and the size of foliage, however, taking these factors into account they can also be evaluated. THE METHOD OF VALUE DEFINITION FOR TREES IS THE FOLLOWING. The value equals the financial appearance of the assimilating surface of the foliage and the produce of these surfaces. It is known how much oxygen and vapour a square metre of leaf surface produces, how much carbon-dioxide and pollutants it binds or absorbs. The size of leaf surface in 1 cubic metre of foliage is known. Earlier results of research are at our disposal (Radó, 1978), according to which an average 4 square metre leaf surface can be found in 1 cubic metre foliage. The assimilating produce of foliage and leafs depends on the size and shape. The foliage size of certain types is characteristic of the type and the age. Growth can be described by the so-called growth curve. The foliage shape influences the value since the cubic volume of a regular globe is different from an egg like shape, for example, thus the assimilating surface size is also different. Primarily we defined the growth curve characteristic of each tree type. Software specially developed for this purpose was used for the calculations. Later on, in order to make the calculation easier the curves were classified according to whether the type had slow, medium or fast growth and also according to what the life span of the tree was. For example, poplars grow fast and their life span is short, they reach full development by the age of 30 to 40 years and the foliage of the silver poplar is egg shaped. A