The urban landscape becomes increasingly great importance in the urban environment. The establishment of a vegetal landscape ranges from a merely visual aspect to a physical or visual barrier, a shadow generator in parks or gardens, etc. In addition, in cases where there is a large concentration of trees, it can be a lung to decongest the atmospheric environment of the city.
URBAN LANDSCAPING AND ITS CONSIDERATIONS
Benefits of tree implantation in urban landscaping:
- Release oxygen
- Regulate temperature and humidity in the urban environment
- Set and absorb dust
- They filter radiation
- Dampens noises
- They favor the presence and implantation of fauna.
From a technical point of view, the ideal selection of the tree goes beyond the color or height that it can achieve, the latter being the one that generates the greatest problems because the development in width (ramifications) or height is not fully taken into account. (bearing).
SELECTION OF VARIETIES AND PREVIOUS CONSIDERATIONS
The selection of trees in urban landscaping should not remain solely on the visual aspect and there are a number of guidelines that must be evaluated. Logically, some of these guidelines will have more weight with respect to others (visual aspect versus resistance to pests and diseases, resistance to salinity in maritime environments versus water needs, etc.). These are the points to analyze when selecting plant varieties in urban landscaping.
- Light needs (sun and shade)
- Resistance to pests and diseases
- Resistance to urban pollution
- Edaphological requirements
- Water requirements
- Adaptation to the climate (hot or cold)
- Color and seasonality
- Tree texture
- Tree growth and development
- Size, structure and shape
It is a special condition in tree selection and urban landscaping. For a park or garden, tall or large trees and generators of a large area of shade will be required.
Ratio of trees with respect to the size in the plantation and the final size:
The above table is of vital consideration for the urban designer, and as many times this work is left in the hands of people without agronomic knowledge, we find countless cases in which the growth of the tree causes problems in the urban landscape. Trees that block the view of buildings, roots that destroy sidewalks, branches that disturb vehicle traffic, etc.
URBAN FACTORS TO TAKE INTO ACCOUNT ACCORDING TO THE GROWTH OF THE TREE
- Overhead electrical wiring
- Street lighting
The tones: Depending on the form of the urban landscaping , different tones can be generated, from common colors (green and brown leaves in autumn) to pink colors such as Japanese plum or almond tree.
This concept of tonality is part of the designer’s choice, adapting it correctly to the environment.
Allergies: a fairly common situation is the use of olive trees in roundabouts or gardens. The establishment of this tree in urban situations can generate allergic problems, and it can be easily substituted by trees of similar size, such as the carob tree.
Here you can see a calendar of species that cause respiratory problems in Spain.
Maintenance: a consideration of special attention is the care that the tree may need as well as its susceptibility to pests or diseases. As a general rule, resistant trees with lower water needs should be selected, without necessarily detracting from the visual aspect . Pruning will be especially important, not only for the health of the trees but also to redirect the growth of the tree and change its structure, when the time comes. For example, avoid the formation of low branches that impede the movement of people on the road, branches that hide traffic signs, or disturb the traffic of heavy vehicles.
As a general rule, the soil in cities is poor, eroded and with a high rock content. The selection of resistant trees should be considered, especially in completely urban land, sidewalks or streets (I think that very few times we have been able to see the incorporation of fertilizer to the trees of urban landscaping, except large gardens) and give it less importance the case of parks and promenades with a higher percentage of land, mineral content and greater care. In addition, it is necessary to plan the growth of the roots, already in the subsoil there are pipes, electrical wiring, sewers or underground, which can be affected by their growth.
TREES MORE RESISTANT TO POLLUTION
This is an important criterion in the urban landscaping of metropolitan cities with high levels of pollution. In summary, in some cities certain sensitive trees will have great problems of adaptation to the environment. Let’s look at the trees that resist (as well as they can) high levels of contamination:
- Acer negundo
- Acer pseudoplatanus
- Aesculus carnea
- Allianthus altissima
- Prunus (genus)
- Robinia pseudoacacia
- Quercus rober
- Populus alba
- Pear and apple trees
- Berberis sp.
- Hibiscus syriacus
- Sage, rosemary and other aromatic species
This is the beginning of an exhaustive analysis that we will add little by little, with more information and depth on the subject.