Analiza regeneracije gozda po požaru : diplomsko delo

Masle, Andraž (author), Grigillo, Dejan (mentor), Potočnik Buhvald, Ana (comentor)

Diplomska naloga obravnava regeneracijo gozda po požaru na Krasu julija 2022, ki je prizadel 3.707 ha površin, od tega 2.902 ha gozda. Namen raziskave je bil s satelitskimi posnetki Sentinel-2 analizirati časovni potek obnove vegetacije v treh letih po požaru ter oceniti, kako hitro in kje poteka regeneracija. Uporabljeni so bili spektralni indeksi, in sicer normiran diferencialni vegetacijski indeks (NDVI), normirano razmerje zgorelosti (NBR), diferencialni NBR (dNBR) in relativni diferencialni NBR (RdNBR), ki omogočajo spremljanje fotosintetske aktivnosti, strukturne obnove vegetacije ter intenzitete požara. Analiza temelji na desetih posnetkih iz obdobja 2017-2025, ki so bili obdelani v programu QGIS. Vsi sloji so bili prostorsko usklajeni, prevzorčeni na prostorsko ločljivost 10 m in izrezani na območje požarišča, določenega z vektorsko datoteko aktivacije EMSR604 storitve Copernicus Emergency Management Service (Copernicus EMS). Ta sistem Evropske komisije je namenjen kartiranju naravnih nesreč na podlagi satelitskih posnetkov. Rezultati kažejo izrazit padec NDVI in NBR neposredno po požaru, kar potrjuje popolno uničenje vegetacije in izgubo vlage v rastlinskem tkivu. Prvo leto po požaru (2023) regeneracija še ni bila zaznavna, kar je posledica obsežne poškodbe tal in koreninskih sistemov. V drugem letu (2024) je prišlo do najintenzivnejše obnove. NDVI je dosegel 75%, NBR pa 57% predpožarnega stanja. Tretje leto (2025) se je regeneracija nadaljevala počasneje, NDVI je dosegel 86%, NBR pa 74% referenčne vrednosti. Primerjava indeksov razkriva, da NDVI hitreje doseže predpožarne vrednosti, medtem ko NBR zaradi občutljivosti na vsebnost vode bolje odraža dejansko strukturno obnovo gozda. Prostorska analiza regeneracijskega indeksa (RI), ki meri spremembo vrednosti NBR glede na stanje takoj po požaru, potrjuje, da je intenziteta požara ključni dejavnik hitrosti obnove. Rezultati so skladni z ugotovitvami literature za sredozemske ekosisteme, hkrati pa odražajo specifične pedološke in klimatske razmere Krasa, ki regeneracijo upočasnjujejo.

• Language: Slovenian
• Keywords: diplomske naloge, požar, regeneracija gozda, daljinsko zaznavanje, NDVI, NBR, Kras, Sentinel-2
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [A. Masle]
• Year: 2026
• Number of pages: 1 spletni vir (1 datoteka PDF (29 str., [15] str. pril.))
• PID: 20.500.12556/RUL-187990
• UDC: 528.8:630*432(497.4)(043.2)
• COBISS.SI-ID: 291542275
• Publication date in RUL: 17.09.2026

Secondary language

• Language: English
• Title: Forest regeneration analysis after the wildfire

Abstract

The thesis investigates post-fire forest regeneration following the July 2022 wildfire in the Kras region, which affected 3,707 ha of land, including 2,902 ha of forest. The aim of the study was to analyse the temporal dynamics of vegetation recovery during the three years following the fire using Sentinel-2 satellite imagery and to assess how quickly and where regeneration occurred. The spectral indices used were the Normalized Difference Vegetation Index (NDVI), Normalized Burn Ratio (NBR), Differenced Normalized Burn Ratio (dNBR), Relative Differenced Normalized Burn Ratio (RdNBR), and Regeneration index (RI), which enable the assessment of photosynthetic activity, structural vegetation recovery and fire severity. The analysis is based on ten Sentinel-2 images from 2017-2025, processed in QGIS. All layers were spatially harmonised, resampled to a spatial resolution of 10 m, and clipped to the burn area defined by the EMSR604 activation of the Copernicus Emergency Management Service (Copernicus EMS). This European Commission service provides satellite-based mapping of areas affected by natural disasters. The results show a substantial decline in NDVI and NBR immediately after the fire, indicating severe destruction of vegetation and loss of moisture in plant tissue. In the first year after the fire (2023), regeneration was not yet detectable, which can be attributed to extensive damage to the soil and root systems. The most pronounced recovery occurred in the second year (2024), when NDVI reached 75% and NBR 57% of pre-fire state. In the third year (2025), regeneration continued at a slower rate, with NDVI reaching 86% and NBR 74% of the reference values. Comparison of the indices shows that NDVI reaches pre-fire values more rapidly, whereas NBR, due to its sensitivity to water content, better reflects the actual structural recovery of the forest. Spatial analysis of the Regeneration Index (RI), which measures the change in NBR relative to the state immediately after the fire, indicates that fire severity is a key factor influencing the rate of recovery. The results are consistent with findings reported in the literature for Mediterranean ecosystems, while also reflecting the specific pedological and climatic conditions of the Kras region, which slow the regeneration process.

• Keywords: graduation thesis, wildfire, forest regeneration, remote sensing, NDVI, NBR, Sentinel-2, Kras