La mappatura di Città metropolitana di Milano

(Ita) L’analisi dei sistemi di cmm

In order to develop an urban forestry strategy that considered the territory in a holistic way, the presented research was the result of analyzing the entire metropolitan area of the city, based both on the cross-examination of data deriving from different databases as well as the recovery of historical documents. One such example of historical documentation utilized was aerial footage captured by the Air Force in 1936, which was of use in clearly visualizing the physiognomical changes of natural systems in recent decades. Three interdependent systems that effectively describe the territory in all of its complexity and help to better articulate the effectiveness of a strategic proposal have been identified:

THE ANTHROPIZED SYSTEM ertaining to the urban sphere and anthropic activities, maps the Land use on permeable and impermeable surfaces. It was updated from the DUSAF (the multi-temporal geographical database of the Lombardy region that classifies the territory on the basis of the main types of cover and land use), to the DBT (Topographical Database which represents and describes the topographical objects of the territory), to finally to the SIARL (the Agricultural Information System of the Lombardy Region).

THE ENVIRONMENTAL SYSTEM is mainly composed of green systems and tree cover. The tree canopy cover represents the indicator of vegetation density commonly used in urban forestry as a more effective alternative to the number of trees when measuring the actual consistency of vegetation within the territory. It is an indicator that represents the projection of the crowns of trees on the ground. Once the mapping of the total area of tree canopy cover has been calculated - thanks to the use of satellite images and other GIS data sources - the tree count can be accurately estimated. To this end, the tree canopy itself is measured against the land usage when determining the available planting layouts (ie. the number of trees per hectare).

Today it is estimated that there are roughly 10 million trees in the metropolitan city.

THE CLIMATE SYSTEM is the complex interactive system concerning 5 components: the atmosphere, the hydrosphere, the cryosphere, the land surface and the biosphere. The Metropolitan City of Milan is an area affected by high average temperatures, and has seen an increase in the number of summer days in which the maximum temperature exceeded 29°, the number of consecutive days without rain and the frequency of intense meteoric events. The study of these variations and the mappings present in the research make it possible to orient urban forestry interventions towards the mitigation of climate risks linked to extreme temperatures and intense rainfall through the intervention of waterproofed soils, de-paving and planting of trees in grey areas.

THE POTENTIAL ASSESSMENT

The research efforts also provide an estimate on the potential of urban forestation in the metropolitan city in order to validate the objective of planting 3 million trees. The potential assessment allows for the identification of different project focuses and their respective quantitative potentials, providing a valid tool to support the decision and planning of interventions.

COUNTING PLANNING PLANS 2018-2021

The sharing and cataloguing of planting activities in their entirety across the individual territorial bodies, municipalities and parks within the metropolitan area was a fundamental component of the research, and directly led to the creation of new synergies and the spreading of awareness of the common objective.

2018 – 2020

88.187

planted trees, forest plants and shrubs
2019 – 2020

76.577

planted trees, forest plants and shrubs (out of 101,443 planned, due to postponements or cancellations due to Covid-19)
2020 – 2021

115.886

planted trees, forest plants and shrubs (mapping process in progress)

RELATIONS WITH MUNICIPALITIES

During the implementation of the project, a great deal of work was carried out in collaboration with the 133 municipalities that make up the metropolitan city. Through a listening and communicative approach, the availability, priorities, and capacity for development of the territory over the years were able to be accurately defined - an approach that furthermore led to a strong diverse network including municipalities, farmers, land owners, environmental associations and private companies among others.

As of September 2020, 229 areas have been identified for a total of 6,740,200 square meters, and is constantly growing.