Design of private gardens in Salzburg
Private greenery can make a major contribution to the climate. Nobody knows how big the total area of Salzburg’s private gardens is and what grows there.
In Austria there are more than two million gardens, around 1.3 million balconies and almost a million terraces. Some are green, some grey. The “Gardens of Horror” page shows what excesses the love of stone and concrete has in the private garden scene Facebook and Instagram. There the German botanist and biologist Ulf Soltau posts articles on “gravel garden culture” in Germany.
Low-maintenance private gardens with no benefit for biodiversity
In the city of Salzburg, 58 percent is green space, nobody knows how much of it is made up of private city gardens, not even the city administration, as the office of the responsible city councilor, Barbara Unterkofler, tells us. How these gardens are designed remains the responsibility of the landowners. All a matter of taste too.
Above all, the Austrian private garden should be easy to care for, supervised by Rosemarie Stangl from the Institute for Biological Engineering and Landscaping at BOKU Vienna. For them, gray concrete deserts in private gardens are alarming, “everywhere is sealed, including the front yards. Paving stones usually have no open joints through which water can seep.” Everyone wants to keep their garden weed-free, minimal effort and aesthetically “clean”. The many new construction projects in which the soil structure and any vegetation are radically removed are particularly important to her. Allowing a minimum of gardening, it often includes plants with sterile flowers with no benefit to biodiversity.
The urban ecologist at the University of Salzburg, Jürgen Breuste, knows all too well that private gardens as an important contribution to the environment are not necessarily the focus of local authorities. He is currently writing a textbook on urban gardens, which are given too little attention in the city ecosystem, also in Salzburg. These gardens make a whole range of valuable contributions: They are used for recreation, regulate the climate and water balance, are used for food production, are habitats for many creatures and contribute to urban biodiversity. The trees are particularly valuable there, emphasizes Breuste. However, there is no precise overview. Recommendations on the subject of the garden ecosystem are not exactly developed in Salzburg, at least that is his experience. The German city of Saarlouis, on the other hand, gives its homeowners trees for their front gardens – a small contribution to climate protection.
It is imperative to preserve healthy soils
Unpaved, species-rich gardens with various growth heights and age structures provide important and valuable ecosystem services, they buffer heat and rainwater, serve to recharge groundwater and are a source of food, all important contributions, especially in times of inner-city densification. In Salzburg, this is currently being funded with the “Bonus” project. It is a question of promoting internal development and densification through the expansion of existing single and two-family houses, which after all make up more than 50 percent of the building stock in the city of Salzburg.
The prevailing opinion here is that there is enough greenery growing around the cities anyway, says Rosemarie Stangl from BOKU Vienna, from this perspective the healthy inner-city soil is not of great importance. “It’s not just about maintaining healthy soil. You have to keep surfaces open to evaporation and runoff, and that requires healthy soil,” she points out.
The opposite occurs: more and more healthy soil structure, which develops over a hundred years and more, is concreted over and withdrawn from use. A short lawn, on which the robot lawn mower mows almost continuously, gives biodiversity no chance, insects and animals are endangered by the stress and the mowing blades and flee. This soil only provides the benefits of evaporation, which is counterproductive in dry areas.
More “Urban Cool Spots” for the cities
Photosynthesis and conversion of CO2 in oxygen mean cooling in regions that are becoming hotter, this has been scientifically proven. “Urban Cool Spots” are becoming increasingly important in urban areas, even if the cooling effect is managed more or less with the boundary to the built area. From this point of view, the green private garden is of particular benefit to the owners, tenants and neighboring neighbors themselves. Thermal images of so-called “Urban Heat Islands” show that on hot days it is up to ten degrees warmer in the heavily sealed city areas than in the unsealed surroundings . In addition, says Rosemarie Stangl, modern architecture does without gabled roofs where heat can collect. In the new buildings with flat roofs, heat often builds up, and if there is no preliminary shading from trees and garden vegetation, you create your own “heat islands”. The engineering biologist therefore warns against quick deforestation: Every tree in the old stock that IS felled is a great loss. Young trees need decades to promote their ecological effect.
How could the importance of the topic be brought closer to the property owners? Urban ecologist Jürgen Breuste emphasizes: “Anyone who wants to garden in a way that is close to nature will find a great deal of information on the internet. Emotionally colored campaigns such as the bee topic could attract more attention. In Germany, there is currently a demand that two percent of the land area be left to the wilderness. Breuste thinks that’s a good thing, provided that the decision to use it is made in a targeted and balanced manner. But he already sees potential for discussion here: if arable land or alpine pastures become overgrown, this would probably result in complaints from tourism because it takes away from the visually “clean” landscape. We need more courage for Gstätten, says Jürgen Breuste. As far as inner cities are getting hotter, the biologist contradicts the old town statute: “Just because Wolfgang Amadeus Mozart didn’t have a tree in Salzburg’s inner city doesn’t mean that none can be there today.”
TIPS
Avoid paving and concrete joints wherever possible and leave the floor open. Use lawn pavers, provide paving stones with large open joints, where the green can grow and be cut with the lawnmower. In gardens there should be wild corners where weeds are allowed to grow, which often provide valuable pollen food. Avoid robotic lawnmowers if possible.