Analisi quali-quantitativa dei residui vegetali prodotti dalla manutenzione del verde urbano di Roma
Author(s)
Stirpe, Filippo
Date Issued
February 26, 2009
Type
Doctoral Thesis
Abstract
The City of Rome owns and manages about 150,000 trees along the city streets, the so-called "urban trees."
Each year approximately 20,000 trees are subject to ordinary pruning.
The yards of pruning of urban trees represent a huge resource of wood biomass, left often in order to be
collected in green dumps, or used however in way not appropriated.
Aim of this study is to analyze the work systems in this kind of yards in order to obtain reliable data about the
productivity and the amount of cut biomass.
The analysis object of the study let us make an evaluation of the amount of the different kind of residues
(branches, leaves, fruits, barks), produced by the yards of pruning for each species of tree examined in
Rome.
Therefore we analyzed the work systems in this kind of yards, obtaining data about the kind of prunings
usually done for every species of tree examined.
The companies are generally obliged from the contract to accumulate the residues in areas, often directly
adjacent to the roads, where it’s easy to organize a yard in order to chip the residues with specific
machinery.
Extracted wood from each tree has been analyzed in its dimension, and in its chemical and physical
characteristics, to determine how it could be used for energetic purposes.
The analysis of the yards object of the study has evidenced, that the residual material represents generically
from 0,26 t to 0,41 t in terms of fresh weight, depending on the kind of tree and on the intensity of pruning. In
fact medium intensity prunings interest 20-25 % of the branches, while strong prunings are not so common.
The dimensional analysis of the extracted wood shows that more than 50% of the branches has a diameter
of 10 cm or more, while 40 % has a diameter of less then 10 cm. Smaller material such as leaves, flowers,
fruits and barches has been classified as “other material”.
It was difficult to compare our data with other studies, for there is not a complete and detailed study on the
existing trees in the communal area, their positioning and the parameters. Many studies has been carried out
about prunings in forest yards, others refer about physiology of urban trees related to the architectural
dimension of trees.
It was possible however to make an evaluation of the amount of residues produced by the companies
examined in Rome. They collect 7.000-8.000 t of fresh substance; at least 5-6.000 t could be used for
energetic purposes, in order to supply a thermic plant of about 1 MW.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
Subjects
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