http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Wed, 19 Jun 2013 07:34:22 GMT 2013-06-19T07:34:22Z http://hdl.handle.net/2067/2151 Title: Biomass estimates by satellite data and ground measurements Authors: Chirici, Gherardo; Corona, Piermaria; Marchetti, Marco; Tonti, Daniela; Travaglini, Davide Abstract: L'abstract è disponibile nel file allegato Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2067/2151 2009-12-31T23:00:00Z http://hdl.handle.net/2067/2082 Title: Large-scale monitoring of coppice forest clearcuts by multitemporal very high resolution satellite imagery. A case study from central Italy Authors: Chirici, Gherardo; Giuliarelli, Diego; Biscontini, Daniele; Tonti, Daniela; Mattioli, Walter; Marchetti, Marco; Corona, Piermaria Abstract: Reliable assessment of forest resource stock, productivity and harvesting is a commonly agreed objective of environmental monitoring programs. Distinctively, the assessment of wood harvesting has become even more relevant to evaluate the sustainability of forest management and to quantify forest carbon budget. This paper presents the development and testing of procedures for assessing forest harvesting in coppice forests by very high resolution (VHR) satellite imagery. The study area is located in central Italy over approximately 34,000 km2. A set of SPOT5 HRG multispectral images was acquired for the study years (2002–2007). Official administrative statistics of coppice clearcutswere also acquired.More than 9500 clearcuts weremapped and dated by on-screen interpretation of the SPOT5 images. In a subset of the study area various methods for semi-automatic clearcut mapping were tested by pixel- and object-oriented approaches. The following results are presented: (i) clearcut map developed by visual interpretation of the SPOT5 images resulted in high thematic (overall accuracy of 0.99) and geometric (rootmean square error of clearcut boundary delineation of 5.3 m) reliability; (ii) object-oriented approach achieved significantly better accuracy than pixel-based methods for semi-automatic classification of the coppice clearcuts; (iii) comparison between mapped clearcut area and official forest harvesting statistics proved a significant underestimation by the latter (65% of the total mapped clearcut area). A sample-based procedure exploiting VHR satellite imagery is finally proposed to correct the official statistics of coppice clearcuts. Description: L'articolo è disponibile sul sito dell'editore www.sciencedirect.com Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2067/2082 2010-12-31T23:00:00Z http://hdl.handle.net/2067/2092 Title: Confronto sperimentale tra superfici a ceduo tagliate a raso osservate mediante immagini satellitari ad alta risoluzione e tagliate riscontrate amministrativamente Authors: Corona, Piermaria; Giuliarelli, Diego; Lamonaca, Andrea; Mattioli, Walter; Tonti, Daniela; Chirici, Gherardo; Marchetti, Marco Abstract: The aim of this work is to test the potential of SPOT5 satellite images for monitoring coppice clearcuts. The clearcuts, delineated by on screen interpretation of the satellite images, are compared with the administrative statistics reported for a sample of 230 administrative units. Administrative statistics result significantly lower than those by satellite images, with an average ratio between clearcut area observed by SPOT5 images within each sample unit and the corresponding administrative statistics equal to 1.45. The underestimation by the administrative data is likely due to the simplified process of authorization of coppice clearcuts as well as the eventual lack of timeliness and/or loss of data that sometimes hinder the information flow from administrative bodies to National Forest Service, that is in charge of feeding the official forest statistics. In the light of the experimentation carried out, an operational procedure by SPOT5 images is proposed for the statistical calibration of administrative data about coppice clearcuts. Description: L'articolo è disponibile sul sito dell'editore www.sisef.it Sun, 31 Dec 2006 23:00:00 GMT http://hdl.handle.net/2067/2092 2006-12-31T23:00:00Z http://hdl.handle.net/2067/2117 Title: Post fire natural regeneration monitoring with the integrated use of high resolution remotely sensed images: the case study of the Pineta di Castel Fusano Authors: Chirici, Gherardo; Balsi, Marco; Bertini, Roberta; Bonora, Nico; Chiavetta, Ugo; Ottaviano, Marco; Corona, Piermaria; Lamonaca, Andrea; Giuliarelli, Diego; Mastronardi, Alessandro; Nardinocchi, Giovanni; Sambucini, Valter; Tonti, Daniela; Marchetti, Marco Abstract: La pineta di Castel Fusano (Roma) è stata colpita il 4 luglio del 2000 da un importante incendio boschivo in seguito al quale si è avviata nell’area una intensa rinnovazione naturale sia per via gamica che agamica. Ai fini di monitoraggio della suddetta rinnovazione sono stati realizzati una serie di rilievi a terra in aree campione nel 2003 e nel 2006. Negli stessi anni è stata acquisita la copertura di immagini telerilevate multispettrali ad altissima risoluzione Ikonos e Quick Bird. Scopo del presente lavoro è la sperimentazione di diverse metodologie finalizzate alla modellizzazione delle relazioni esistenti tra i dati telerilevati acquisiti e le misure realizzate a terra per la stima e la mappatura dei fenomeni di rinnovazione gamica e agamica. Sono stati per questo sperimentati metodi sia tradizionali di analisi regressiva multivariata, sia di tipo non parametrico, con algoritmi basati su reti neurali (Relevance Vector Machine e Multi-Layer Perceptron) e k-Nearest Neighbors. Le attività si inquadrano nell’ambito del progetto GRINFOMED - MEDIFIRE per il quale è stato realizzato un apposito software denominato Spatial Forest Modeller (SFM) capace di analizzare le relazioni tra variabili telerilevate e misurate a terra e di individuare i modelli predittivi migliori in modo da derivare mappe tematiche delle variabili acquisite mediante campionamento a terra. Il contributo illustra i dati acquisiti, le metodologie di analisi e di modellizzazione e i risultati ottenuti. Viene inoltre illustrato il funzionamento del software SFM.; Stone pine stand of Castel Fusano (Rome) burnt on July the 4th 2000 during a huge wildfire. As a consequence of the fire an intensive natural sexual and asexual regeneration began. In order to monitor such a regeneration field surveys were carried out in 2003 and 2006 in sample plots. Remotely sensed high resolution images from Ikonos and Quick Bird were acquired for the same years. The purpose of this work is to test different methodologies for modeling existing relationships between remotely sensed images and ground collected data in order to estimate and to map both sexual and asexual regeneration. For such a purpose different methodologies were tested: step-wise Muliple Linear Regression, Neural Networks (Relevance-Vector-Machine and the Multi-Layered-Perceptron) and the k-Nearest-Neighbors. These activities were carried out within the framework of the GRINFOMED- MEDIFIRE also developing a specific software named Spatial Forest Modeler (SFM) able to analyze existing relationships between remotely sensed variables and data collected in the field in order to identify the best available models to map and estimate the studied variables acquired on the basis of a field sampling design. The present paper presents data collected in the field, analysis and modeling methods and achieved results. The SFM software is also presented. Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2067/2117 2007-12-31T23:00:00Z