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Fall trees, when the replacement is a tough job

The current season, particularly rich in rainfall, has caused several tree failures and brought to the attention of the public the problem of managing old and senescent trees in the urban environment. This is a problematic issue that, in some cases, needs to be addressed without further delay and must be managed not only technically, but also paying attention to the communication aspects which are highly to manage the disputes and meet the expectations and to the demands of citizenship.

Psycology and management. This said, it must be stressed the importance of "historical" and environmental impact of some individuals (trees create a shady "meso-environment" which greatly mitigates the summer temperature and clean the air), so that the removal of entire rows or groups of plants and their subsequent replanting doesn’t always appear to be a viable solution for single historical trees or for those which characterise a certain part of the city.

In these cases, we might suggest a management solution that provides a gradual renewal of the trees, safeguarding the visual continuity of the tree avenue over time. If we could begin today to replace the trees in the most critical conditions, continuing in a progressive manner, we will ensure, at the same time, safer conditions along with the permanent presence of a tree-lined avenue. It is, therefore, reasonable to replace all the trees over a period of time not exceeding 15-20 years, in order to replace 5 to 6.7% of trees/year. This can be programmed in accordance with the nurserymen so that they can plan tree production and provide progressively bigger and ready-to-plant trees so as to ensure a certain size uniformity.

Total replacement, an high-impact decision. In other cases, it may also be taken into account the possibility of entirely removing a tree avenue to re-establish a new one with high quality tree, planted at the right distance and technically and economically well managed, so to simultaneously ensure the safety of the citizen. The complete replacement allows to have coeval and homogeneous plants, which can however be reached, as said, also with replanting "batches", planning the various intervals with plants of progressively larger sizes prepared in nursery with a long term programming. It is clear that this choice implies that some politically "strong" and perhaps unpopular decisions must be taken when the trees are old, sick or injured, but still have high sentimental value for citizens and when the emotional impact for their removal is relevant. Unfortunately, it is sometimes necessary to make these choices to contribute to the development of sustainable cities using the trees in the best way to improve air and water quality, reduce energy costs and, at the same time, to provide the best habitat for humans and for the conservation of animal species. Many cities, also in our country, already have a good amount of green areas. The challenge is to take this “green heritage” to protect and manage it, but also to enrich it further to create a legacy to pass on to future generations of citizens. Examples already exist in various parts of Europe and from these it’s possible to draw inspiration, but is also vital to develop new approaches and apply new solutions to address current and future challenges.

A future challenge. The greatest challenge is to contribute to the development of sustainable cities using the trees in the best way to improve air and water quality, reduce energy costs and at the same time, provide the best habitat for the people and for the conservation of animal species. A good quality urban green does not occur by accident: a careful planning and an equally careful design is needed to ensure that the trees located in urban green areas, parks and along the roadways urban and suburban, might improve the urban landscape and provide services that encourage people to use green areas as part of their daily lives. For this they should be comfortable, safe, attractive and promote the widest possible variety of uses.

Some urban areas experience fall trees frequently and these incidents are more and more frequent, it’s not only a technical problem it’s also due to climate conditions.

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