1,720,963 research outputs found
Applicazione di tecniche di telerilevamento per la stima di parametri dendro-auxometrici a diversa scala in popolamenti forestali
Get PDFIl Telerilevamento è diventato una tecnologia insostituibile per il monitoraggio delle foreste a tutte le scale spaziali, a fini scientifici, pianificatori, gestionali e operativi, tanto da essere diventato onnipresente all’interno della Selvicoltura di precisione. Il Telerilevamento fa parte a sua volta degli strumenti e tecniche della Geomatica che supportano ad analizzare dati, estrarre informazioni e metterle a disposizione degli utilizzatori finali, anche attraverso i Sistemi di supporto alle decisioni. Questo elaborato presenta tre applicazioni di telerilevamento e geomatica legate al contesto territoriale del Friuli Venezia Giulia.
Il primo studio ha riguardato la stima spazialmente esplicita di volume legnoso e incremento legnoso corrente annuo per l’intera superficie forestale del Friuli Venezia Giulia mediante l’utilizzo di dati telerilevati, e dell’Inventario forestale nazionale 2015 usati in un algoritmo Random forest. Tra i dati in ingresso, sono state utilizzate come variabili indipendenti quattro indici spettrali calcolati da Sentinel-2 tramite Google Earth Engine, un modello di altezza delle chiome e tre descrittori della geomorfologia. I risultati sono due mappe raster a risoluzione 23 x 23 m, e dimostrano l’importanza dell’impiego dei dati LiDAR ad alta densità, ma anche l’apporto dei dati satellitari.
Il secondo articolo riguarda la realizzazione di un sistema di supporto alle decisioni forestale finalizzato ad assistere le utilizzazioni e la pianificazione di dettaglio, integrando i dati generati dalla prima ricerca. Questo nuovo strumento è stato sviluppato aggiornando e unendo insieme diverse fonti di informazioni disponibili (ad esempio, composizione delle specie arboree, presenza di aree protette, strade forestali, ecc.) con nuovi livelli ad hoc quali l’accessibilità con due mezzi da esbosco, ed elaborando anche un'analisi dei costi relativa ai diversi possibili metodi di raccolta del legname. Il sistema è stato testato e diffuso tra i professionisti, funzionari regionali e amministrazioni, dimostrandone la facilità d’impiego e l’utilità.
L’ultimo, prende le mosse dal grande incendio del 2022 che ha colpito i boschi del Carso tra Italia e Slovenia. Nasce dall’esigenza di raccogliere dati sull’estensione e severità dell’incendio, applicando l’indice spettrale differenced Normalized Burn Ratio (dNBR), e che ha consentito un approfondimento con i dati raccolti in campo sulle specie vegetali. I risultati mostrano che incendi intensi causano una significativa mortalità degli alberi e modificano profondamente la composizione della vegetazione, favorendo la diffusione di specie arbustive e erbacee, alcune delle quali aliene e invasive. L'aumento dell'eterogeneità degli habitat, pur favorendo la biodiversità a breve termine, potrebbe comportare cambiamenti a lungo termine nella struttura e nel funzionamento dell'ecosistema. Lo studio sottolinea l'importanza di considerare la gravità degli incendi nella pianificazione delle strategie di conservazione e gestione forestale.Remote Sensing has become an irreplaceable technology for forest monitoring at all spatial scales, for scientific, planning, management and operational purposes, so much so that it has become omnipresent within Precision Forestry. Remote Sensing is in turn part of the Geomatics tools and techniques that support data analysis, information extraction and making it available to end users, also through Decision Support Systems. This paper presents three applications of remote sensing and geomatics related to the territory of Friuli Venezia Giulia.
The first study concerned the spatially explicit estimation of growing stock and current annual increment for the entire forest area of Friuli Venezia Giulia through the use of remote sensing data, and the 2015 National Forest Inventory used in a Random forest algorithm. Among the input data, four spectral indices calculated by Sentinel-2 via Google Earth Engine, a canopy height model and three geomorphology descriptors were used as independent variables. The results are two raster maps with a resolution of 23 x 23 m, and demonstrate the importance of using high-density LiDAR data, but also the contribution of satellite data.
The second article concerns the creation of a forestry decision support system aimed at assisting utilization and detailed planning, integrating the data generated by the first research. This new tool was developed by updating and merging together different sources of available information (for example, composition of tree species, presence of protected areas, forest roads, etc.) with new ad hoc levels such as accessibility with two logging vehicles, and also developing a cost analysis relating to the different possible methods of timber harvesting. The system has been tested and disseminated among professionals, regional officials and administrations, demonstrating its ease of use and usefulness.
The last one, starts from the great fire of 2022 that hit the forests of the Karst between Italy and Slovenia. It arises from the need to collect data on the extension and severity of the fire, applying the spectral index differenced Normalized Burn Ratio (dNBR), and which has allowed an in-depth analysis with the data collected in the field on plant species. The results show that intense fires cause significant tree mortality and profoundly modify the composition of the vegetation, favoring the spread of shrubby and herbaceous species, some of which are alien and invasive. The increase in habitat heterogeneity, while favoring biodiversity in the short term, could lead to long-term changes in the structure and functioning of the ecosystem. The study underlines the importance of considering the severity of fires in planning forest conservation and management strategies
Increasing the value of windstorm damaged forest: combining restoration practices and agroforestry
No full textMapping Forest Growing Stock and Its Current Annual Increment Using Random Forest and Remote Sensing Data in Northeast Italy
Get PDFThe role of forests in providing multiple goods and services has been recognized worldwide. In such a context, reliable spatial predictions of forest attributes such as tree volume and current increment are fundamental for conducting forest monitoring, improving restoration programs, and supporting decision-making processes. This article presents the methodology and the results of the wall-to-wall spatialization of the growing stock volume and the current annual increment measured in 273 plots of data of the Italian National Forest Inventory over an area of more than 3260 km2 in the Friuli Venezia Giulia region (Northeast Italy). To this aim, a random forest model was tested using as predictors 4 spectral indices from Sentinel-2, a high-resolution Canopy Height Model derived from LiDAR, and geo-morphological data. According to the Leave One Out cross-validation procedure, the model for the growing stock shows an R2 and an RMSE% of 0.67 and 41%, respectively. Instead, an R2 of 0.47 and an RMSE% of 57% were obtained for the current annual increment. The validation with an independent dataset further improved the models’ performances, yielding significantly higher R2 values of 0.84 and 0.83 for volume and for increment, respectively. Our results underline a relatively higher importance of LiDAR-derived metrics compared to other covariates in estimating both attributes, as they were even twice as important as vegetation indices for growing stock. Therefore, these metrics are promising for the development of a national LiDAR-based model
Impact of salvage logging on short-term natural regeneration in montane forests of the Alps after large windthrow events
Get PDFWind disturbances are one of the main drivers of forest dynamics in Europe, shaping forest stands and modifying the ecosystem services provisioning. Salvage logging is often most common strategy adopted after a high-severity disturbance in managed stands. Understanding natural regeneration dynamics including their interaction with the logging operations, is crucial to understand how forests will be changing under a climate with increasing variability and to design adequate adaptive post-disturbance management strategies. In this study, we focused on 148 stands damaged by storm Vaia (2018). The aim was to analyze natural regeneration dynamics under different logging systems and to investigate influences of site characteristics and disturbance legacies on sapling growth and seedling emergence. The sampling protocol consisted of one transect per stand, perpendicular to one of the intact forest edges, and with a length of 80 m. Along the transect, we collected soil cover, natural seedling and sapling stem density, and deadwood quantity in four sample plots of 3 m radius each at distances of 0, 20, 40, and 80 meters from the edge (592 plots in total). Regeneration species composition was mainly driven by previous stand composition, with some exceptions depending on seed dispersal strategy. Distance from the edge significantly influenced seedlings and saplings occurrence in large gaps and affected the browsing damage percentage, together with deadwood presence. According to GLM’s models, distance from the edge, elevation, and logging methods influenced seedling establishment. At the same time, species characteristics, edge structure, deadwood and logging damages significantly influenced pre-storm seedlings and saplings presence and health. In conclusion site factors, disturbance legacies, and logging strategies are key points to consider in post-disturbance management for a fast forest recovery
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Scheda della rete della mobilità lenta
No full textLa scheda propone quadri conoscitivi, analisi, interpretazioni e strategie in riferimento agli assi della mobilità lenta (ciclabili, cammini, vie d'acqua) in grado di costituire una rete per la fruizione paesaggistica in Friuli Venezia Giulia
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
