Availability of Public, Near-residential Green Spaces 1992
The inventory analysis covered all open spaces listed in the Green Space List, and hence open to the public, with the use type “park and green spaces.”
For the East Berlin boroughs, the probable status of the open spaces first had to be determined, since the major part of the areas listed in the Green Space List, at the time of compilation, were still in the hands of the boroughs, and thus under the legal auspices of the Green Space agencies, although a reorganization and/or change of ownership was to be expected for many areas.
Areas which, according to estimation of the Green Space agencies, would remain under their jurisdiction, and would in addition retain their public character, were classified as public. The basis for this estimation was, as a rule, preliminary consultation between the Conservation and Green Space agencies, the Urban Planning Agency, Public Housing Companies and the Trust Holding Agency (Treuhand) (as of November 1991). The inventory analysis incorporated all parks and city squares, but also areas within those new residential areas generously interspersed with green spaces, for instance, along the so-called “supply corridors” or in the large residential courtyards, provided these constituted an unbroken area of more than 1 ha, and were generally accessible.
The statements regarding probable status of the areas represent the status as of November/December 1991, and are to be reexamined after clarification of ownership and responsibilities.
Appraisal of the Suitability for Recreation
Since near-development green spaces can also fulfill the function of a near-residential open space, the appraisal of the suitability for recreation covered all green spaces over 0.5 ha with regard to the observance of the minimum requirements for near-residential open space examined (cf. Kellermann 1974). The appraisal of the green spaces was based on the existing data and map material.
The following criteria were used for the appraisal:
Open spaces for near-residential recreation must have a minimum size of 0.5 ha, to make the type-specific use possible. For green spaces cut by streets and for which size data for the individual parts is lacking, open spaces are considered only if one of the segments is larger than 0.5 ha.
The open space must be at least in part broader than 15 m. Areas with embankments must have a level space of at least 15 m.
Unhindered accessibility to the open space must be guaranteed. Green spaces may not be surrounded entirely by obstacles which shut out the intake area. Obstacles include heavily-traveled streets (more than 10,000 motor vehicle/day), rail lines, bodies of water and enclosures (such as at the Kaulsdorfer Busch / water reservoir). The possible existence of pedestrian footbridges and/or tunnels, or of traffic lights, which could mitigate the barrier effect at isolated points, was not considered.
Noise pollution and air pollution diminish the recreational value of a period outdoors. Since detailed measurements and/or prepared data in reference to the situation in green spaces were not available at the time of compilation, the pollution factor is here limited to the element of traffic noise.
For green and open spaces, German Industrial Standard (DIN) 18005, 5.87, Sound Protection and Urban Development for Urban Development Planning, specifies a limit of 55 dB (A). With free acoustic propagation, this limit can be reached on a city street with a speed limit of 50 km/h even at a vehicle load of 2,000 motor vehicles per day. Major thoroughfares are as a rule burdened with far more than 10,000 motor vehicles per day. This corresponds to a noise pollution of more than 60 dB (A), and frequently more than 70 dB (A). Intermittent vegetation in green spaces provides no noise buffer. A reduction of the noise can be ascertained solely at increasing distance from the source of the noise. Due to the location of many green spaces on heavily traveled streets, a large number must be considered heavily noise-polluted, and would not therefore be classified as useful for recreation. As a minimum requirement, it was stipulated that at least a part of the open space had to be unaffected by major ecological damage. This criterion was further specified to indicate that an open space on a heavily-traveled street – with a noise level of more than 70 dB (A) – would only be classed as suitable for recreation if it had a minimum depth of 100 m from the street, or a minimum size of 1 ha. Minimum size and/or depth should guarantee that a visit to the open space would be possible at a distance from the street. Green spaces with a size of over 1 ha were thus fundamentally classified as useful.
Minimum requirements with regard to the equipment of open space facilities were not included in the appraisal, since some open spaces examined, especially in East Berlin, are inadequate in terms of equipment. Deficits in this area can be corrected with the appropriation of sufficient funds, however, so that this was not considered a criterion for exclusion.
The Britz Garden in Neukölln und the former horticultural exhibition area in Marzahn constituted two exceptions in the appraisal. Both green spaces are limited in their accessibility by entrance fees, and they do not fall under the responsibility of the Green Space Agencies. Because of their important recreational functions, and the relatively low entrance fees, they were nonetheless classified as fully useful green spaces.
Altogether, 779 public green spaces had a minimum size of 0.5 ha, and were included in the appraisal. Of these, 557 could be classified as fully useful, while 222 green spaces did not meet the standards, 84 of them because of too-high noise pollution levels (cf. Tab. 2).
Survey of Intake Areas
All green spaces which were determined as to be useful were recorded on the basic maps in a scale of 1:20,000, and assigned an intake area.
The intake areas were determined by means of a circle drawn around the respective open space, with the distance determined as the crow flies. To compensate for the difference between this distance and the actual walking distance to the green space, 10% was subtracted from the maximum distance. Thus, a radius of 450 m resulted for near-residential open spaces.
For smaller open spaces, the center was chosen as the point of origin of the radius; for larger spaces, the entrance area was used (approx. 100 m inside the open space).
The intake area of a green space can be reduced by psychological or physical barriers which exist within the intake area. Physical barriers include rivers and canals, railroad lines, airports, and also streets with a traffic volume of over 10,000 motor vehicle per day. The schematically determined intake area was corrected by the consideration of the available barriers.
Wooded areas also were assigned an intake area, provided they fulfilled the minimum requirements for accessibility and size. The assumption was that the edges of forests can assume the functions of a near-residential open space, while for agricultural areas, recreational use is impossible, or is reduced to a few fringe areas.
Calculation of the Degree of Availability
According to the standard value valid in Berlin, the availability of public green spaces to the population at a level of 6 m2 or more near-residential open space per inhabitant is considered sufficient. On the basis of this standard value, the degree of availability (m2 of green space/inhabitant) was broken down into four levels.
The categories are: Areas of availability, where near-residential green space is available at a level of more than 6 m2 per inhabitant (Category 1); Areas of non-availability, which have no useful green space (less than 0.1 m2/inh., Category 4); and Areas of insufficient availability, including all residential areas with a degree of availability between 0.1 and 5.9 m2 /inh. Availability of less than 50% of the standard value, i.e. less than 3 m2/inh., is shown separately (Category 2: 3.0 – 5.9 m2/inh.; Category 3: 0.1 – 2.9 m2/inh.). For the calculation of the respective degree of availability, the number of inhabitants in the intake area of a green space was divided by the size (the calculated population by the m2 of green space). All intake areas of forest edges count as areas of availability.
If statements are necessary on availability in a specific situation, this generalized statement will need to be concretized in order to render a judgment on the possible recreational function of a forest or forest edge.
The superimposition of a matrix of the degree of availability over a map of the construction structure of residential areas provides further insight into the availability situation. It does not, however, provide additional evaluation material.
Deduction of the Housing Type
The construction structure can be examined as an indicator for the available share of private open space. Areas with different construction structures, but with comparable shares of private/semi-public open spaces, were lumped together, and classified into three categories (cf. Fig. 1):
extremely slight share of private / semi-public open spaces
This involves predominantly areas of closed-block development (up to 1914), including all preservation-oriented reconstructed blocks integrated into this construction structure. In addition, core and mixed areas are counted in this category.
slight to medium share of private / semi-public open spaces
To this category belong all construction structures which display large quadrangles or strips of green space (development from the twenties and thirties and/or from the fifties and sixties), and the high-rise apartment developments on the outskirts of town with generous green spaces (green separators) between the buildings. Furthermore, the redeveloped apartment blocks also include closed block development which was decored completely and thus displays larger open spaces.
medium to high share of private / semi-public open spaces
This category includes all open development (for instance single-family or row-house development). The buildings to a large extent have their own gardens, so that the share of private green is very high.