Urban Gardens

Urban gardens can be described as private green spaces belonging to a property within towns and cities. They vary in size from a relatively small patch of green space situated in front of a domestic property, often found in inner-city areas to large spaces surrounding an individual property, exceeding several hundred square meters. Urban gardens provide a haven for a wide range of flora and fauna within urban areas. The urban garden is generally not believed to be exceptional in its species richness, yet it has higher plant diversity than is found in the Amazon rain forest. Many bird species also frequent urban gardens, adding a sense of character to a neighborhood, especially during the summer months.

To understand the benefits of urban gardens, it is useful to explore some of their significant characteristics. These include the following:

• 1.
  High plant diversity
• 2.
  Large number of food chains
• 3.
  Large number of unique habitat zones
• 4.
  Constant state of succession
• 5.
  Disturbed state

The relatively high plant diversity reflects that fact that many gardeners plant as many species as possible. This phenomenon has a knock-on effect, since the numerous varieties of plant species provide the basis for a different food chain. Gardeners are usually keen to create several zones within a garden, such as a water feature, a flowerbed, lawns and hedges, and so on, each of which supports different types of flora and fauna. A constant state of succession is ensured by not allowing a particular plant species to dominate. This has the added advantage of preventing a garden from supporting only a specific plant species such as woodland. Finally, because the garden is continuously subjected to disturbance, it is generally welcoming of foreign species, thus ensuring diversity.

Urban gardens provide a range of benefits to an urban area that are not widely acknowledged. Vegetation is known to have a substantial effect on the temperature, moisture, and precipitation regimes of urban areas. For instance, plants can reduce temperatures by as much as several degrees Celsius in large urban green spaces by increasing the relative humidity of the air, causing it to cool, and counteracting the urban heat island effect. Indeed, a large tree, well supplied with water, has the ability to provide local cooling equivalent to several air conditioners running over much of a day.

Urban gardens have the potential to provide significant benefits to human well-being. In the United States, for example, a study found gardeners consistently reporting the importance of urban gardens in providing an opportunity for exercise and reduction in stress levels. In a U.K. survey, gardeners cited the creation of a pleasant environment and the promotion of relaxation as the two most important aspects of gardens. Other benefits noted were personal satisfaction gained through maintenance and in producing a tidy piece of green space, the health benefits of fresh air and [Page 2934]exercise, a sense of peace and tranquility, and the opportunity to meet and talk with neighbors.

Bird's-eye view of a park six stories above the ground in downtown Tokyo

Source: Lawrence Karn/iStockphoto.

Despite their crucial role in urban society, there is generally a lack of information on the extent of urban garden space because local government is not required to monitor or manage such spaces, yet it is apparent from aerial photography and other sources that they constitute a significant portion of many urban properties and must therefore constitute a sizable proportion of urban areas. This relatively large aggregated green space has the advantage of another very significant feature, namely, flood alleviation. As climate change begins to produce more extreme events such as floods, urban gardens have the distinct advantage of attenuating flood peaks.

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