14 / 55
12
Figure 3
- Examples of forestry interventions aimed to carbon sequestration inside a protected area of Rome
(Natural Reserve of Valle dell'Aniene)
o
•
restrictions and prescriptions. When realizing forestry interventions, it is compulsory to
analyze current local planning instruments and ranking rules (Town Plan, Land Management,
Green Areas Plan, Protected Areas Management Plans, Traffic Laws, etc.). Forestry
intervention, in fact, has to be integrated
in the
local planning context and has to respect what
is provided for by implementation regulations, for example the respect of the smallest
distances from streets. Specifically in Rome, it is necessary to follow what is provided for by
“Guidelines for the management of masts of council ownership in the Roma Capitale
territory” (“Linee guida per la gestione delle alberature di proprietà comunale nel territorio di
Roma Capital
e 19). Finally, it is necessary to check landscape restrictions and all constraints
(such as power lines, aqueducts, gas pipelines, etc.);
•
•
pedological characteristics. It is necessary to assess soil characteristics, which can represent a
limiting factor for plants growing, if it is not suitable for roots penetration. Furthermore, all
actions necessary to prepare adequately the soil before planting can change depending on soil
characteristics (for example if it is necessary to resort to drainage). Therefore, it is important
to analyze soil features, such as structure and texture, rock depth, porosity and permeability,
presence of water and/or of an aquifer, drainage characteristics, pH
20, presence of macro
element
s 21. Particularly, many urban soils can be modified due to compaction events (footfall,
heavy vehicles transit, etc.), alterations deriving from litter and vegetation removal (that
means a change in the organic and nutrient supply in the soil), pH modification (for example
pH is on average high in soil next to streets and buildings). More details on soils in urban
areas and their ecosystem services are provided in the box “Soils in the urban environment”;
•
•
microclimate. Besides the soil, it is fundamental to characterize implantations site from both a
climate (rainfall and temperature) and microclimate point of view (humidity, wind, sunlight
exposure, etc.). The knowledge of all these aspects allows the selection of the most suitable
vegetal associations to plant. Urban environment, in particular, is characterized by higher
temperatures (the so called “urban heat island”) caused by an higher solar energy absorption
on the part of the numerous sealed surfaces (paved streets, buildings), by a drier air and a less
presence of wind (thanks to the many physical obstacles). Furthermore it is necessary to assess
exposure to pollutants (such as traffic congested streets), which represent a source of stress for
19
Deliberation of Town Council (Deliberazione della Giunta Capitolina) n. 307 of 10/17/2014.
20
Species can prefer basic or acidic soil. For example different oak species (turkey oak, holm oak, etc.) prefer basic soil, while cork oak and
chestnut acidic ones.
21
This aspect is crucial in the urban environment, where in the soil it is easier to find building waste and residues, which can create an
unsuitable substrate due to the nutrient lack.