Talking about Urban Forestry is to think about conserving or incorporating selective tree species into cities.
Conserving means to protect the existing trees in the city, to preserve those ancient living beings that surround us, giving them the status of Historic Trees, Remarkable Trees or another nomenclature that protects them for life. Incorporating means we must continue planting trees to neutralize the impact of the city on the environment and the impact of climate change around us.
Under the statement that all trees are good, there are no “good trees” or “bad trees”, we have to study and analyze the benefit or impact of each of these species on the environment that surrounds us.
Knowing that all trees produce oxygen and fixate carbon dioxide, moderating climate change as well as knowing that all of them provide shadow to people and buildings, that they reduce the room temperature, that they very much benefit urban biodiversity, that they filter odors, dust, reduce annoying noises and protect us from strong winds when planted as shelterbelts, that absorb rainwater and retain rainwater on the top the tree and that they reduce the speed with which rainwater and hail reach the ground.
Likewise, if we stop to analyze that indirect benefits are obtained from it such as the incorporation or conservation of permeable soil in cities and that they increase the real estate value of properties, we could conclude that they are all positive ideas.
As well, in this matter we can find different exceptions. Without losing sight of the initial statement that “all trees are good”, both native (specific to each region) and exotic (introduced by people from other regions), we must analyze thoroughly and establish statistics about species of exotic trees that become wild and invasive.
A species becomes wild when they are introduced into a region from which it is not native and finds climate, soil and conditions that lead to its reproduction and propagation. If the expansion of this species reaches the point of invading territories, preventing the development of other native species of trees and typical wildlife of the region, it does not only modify ecosystems, but it also changes enormously the biodiversity.
Birds, mammals, reptiles, insects and other wild animals will be altered by the presence of exotic and invasive species that are not the usual ones in their ecosystem, causing them to disperse and move away from each region in search of food and shelter.
Therefore, we could definitely say that “all trees are good” but each one in its ecoregion or in neighboring regions where part of the biodiversity is shared.
Previously, we stated that the native wildlife that coexist with urban and peri-urban trees since they act as a thermometer that will tell us if we are doing things right or wrong in our ecosystems’ management.
The presence of different species of butterflies, hummingbirds and many other wild animals will let us know that we are on the right path, while in environments modified by the invasion of unknown species we will see the same scarce animal species as in a monoculture forest or in a treeless urban site.
If we could increase urban reforestation as a replacement of trees lining in the sidewalks in streets and avenues, boulevards and recreation areas, the incorporation of native species in the form of biodiversity corridors, micro-forests and the creation of urban reserves will undoubtedly lead us to a healthier life with the environment and will improve the quality of life of its habitants.
One of the main challenges of urban trees is trying to survive the ancient practice of pruning.
The practice of pruning dates back to the beginning of humanity, where the closest trees (private gardens, sidewalks and nearest parks) were pruned to obtain the nearest branches that at the beginning of the winter season would be useful to heat the houses as firewood. Hence, the myth of pruning in autumn is promoted in the collective unconscious.
For that reason, its more than understandable that for centuries until energy and gas began to be used to heat us, trees were pruned to generate firewood. The practice of pruning is in our DNA.
But do trees need pruning? Surely most people would agree that “they sprout stronger” but that is just another ingrained practice that comes from fruit trees.
Nature is wise! If we look at the trees, we can see that they all renew their leaves. The deciduous ones change them all together at a certain time of the year and the evergreen ones change them little by little throughout the year. But we do not know trees that change their branches or that drop all their branches periodically. This shows us that trees do NOT need pruning practices but rather it is a maneuver that we human beings carry out to adjust trees to urban life. It is neither more nor less than a practice for our convenience but that when carried out without technical and professional knowledge, harms the tree and can cause serious risk of injuries to people.
Informing ourselves and training us in urban tree management techniques, will give us the possibility of living in healthier cities but it will also protect us from possible accidents due to action or omission in the decisions we make regarding trees of the cities.
In the same way we would go to repair our car to a professional mechanic, to evaluate the resistance of the roof tile of our home we consult an engineer, to carry out urban tree management practices whether public or private we must consult professionals trained in the matter with their qualifying titles or their proven track record in the matter.
Reforesting cities and protecting existing urban forestry will give us the possibility of living in healthier and much more sustainable cities. Reconnecting with the environment will make us feel much better with our planet, with our fellow human beings and with ourselves.
Let’s keep planting native trees!!
