Kratkoročne posledice gozdnih požarov na različnih drevesnih vrstah v mešanih gozdovih Slovenije

Petek, Iza (author), Nagel, Thomas Andrew (mentor)

Gozdni požari so v naravi prisotni skozi celotno zgodovino obstoja gozdov. Ponekod v svetu so lahko ključnega pomena za ohranjanje gozdov, ker tam omogočajo pomlajevanje in razmnoževanje nekaterih rastlinskih in drevesnih vrst. V Sloveniji pa so požari sicer prav tako prisotni, a večinoma povzročajo veliko gospodarsko in okoljsko škodo. S podnebnimi spremembami, torej dolgotrajnejšimi sušnimi obdobji in višjimi temperaturami, bo le teh najverjetneje vedno več. Eno izmed rekordnih let v zgodovini gozdnih požarov v Sloveniji je bilo leto 2022. Iz teh razlogov smo se lotili podrobnejšega raziskovanja kratkotrajnih posledic, ki jih imajo gozdni požari na mešane gozdove Gorenjske in Osrednjeslovenske regije. Opravili smo meritve na treh pogoriščih različnih obsegov v okolici Ljubljane in Preddvora, na nadmorskih višinah od 319 do 1018 m in naklonih med 19 in 41,4 stopinjami. Opravili smo popolno premerbo dreves s prsnim premerom enakim ali večjim od 5 cm na naključno razporejenih ploskvah radija 12 m. Na teh smo popisali tudi odmrlo biomaso, na manjših ploskvah radija 2 m pa smo popisali pomlajevanje. Vse ploskve popolne premerbe so bile na vzhodnih, južnih ali zahodnih ekspozicijah. Ugotovili smo, da na intenziteto požara vplivajo nekateri topografski dejavniki, kot sta naklon in nadmorska višina znotraj požarišča, zanimivo pa nismo ugotovili povezave med intenziteto požara in prisotno odmrlo biomaso. Za le to pa se je pokazala manjša povezava z mortaliteto dreves, in sicer obstaja statistično značilna povezanost med mortaliteto dreves in debelino skorje. Na mortaliteto dreves vpliva tudi debelina dreves oziroma njihov prsni premer. Delni vpliv smo ugotovili tudi pri debelini skorje oziroma drevesni vrsti. Na splošno pa sta v teh gozdovih vpliv požara in njegove posledice velika. Po enem letu je ostala živih še manj kot tretjina vseh dreves, izmed katerih pa je imelo veliko število dreves tudi večje poškodbe krošnje. Tem še vedno grozi poslabšanje stanja v prihodnjih nekaj letih, predvsem ob večjih ujmah in napadih podlubnikov, ki se že kažejo v letu 2023 ali ekstremnih sušah.

• Language: Slovenian
• Keywords: Gozdni požari, Slovenija, kratkoročne posledice, regeneracija, odmrla biomasa
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [I. Petek]
• Year: 2023
• PID: 20.500.12556/RUL-149777
• UDC: 630*4(043.2)=163.6
• COBISS.SI-ID: 163951363
• Publication date in RUL: 10.09.2023

Secondary language

• Language: English
• Title: Short-term consequences of fire in mixed forests of Slovenia

Abstract

Forest fires have been present in nature throughout the entire history of the existence of forests. In some parts of the world, they can thus be of vital importance for the preservation of forests, where many species have evolved adaptations to survive or regenerate after fire. Fires are also present in Slovenia, but they mostly cause great economic and environmental damage. With climate change, i.e. longer dry periods and higher temperatures, wildfires are likely to increase in the future. One of the record years in the history of forest fires in Slovenia was 2022. For these reasons, we undertook a more detailed investigation of the short-term consequences of forest fires on mixed forests of the Gorenjska and Osrednjeslovenska regions. We performed measurements at three fire sites of different sizes in the vicinity of Ljubljana and Preddvor, at altitudes from 319 to 1018 m above sea level and slopes between 19 and 41.4 degrees. A complete survey of trees with a breast diameter equal to or greater than 5 cm was carried out in randomly distributed plots with a radius of 12 m. Dead biomass was also recorded on these, and rejuvenation was recorded on smaller plots with a 2 m radius. All plots were on east, south, or west expositions. We found that the intensity of the fire is influenced by some topographical factors, such as the slope and altitude within the fire area, but interestingly, we did not find a connection between the intensity of the fire and deadwood biomass. There was a smaller connection with tree mortality though. The latter is also influenced by breast diameter of trees. A partial influence was also found in bark thickness or tree species. In general, however, the impact of fire and its consequences are great in these forests. After one year, less than a third of all trees remained alive, and many of them also had major crown damage. These are still at risk of deterioration in the next few years, especially in the event of major damage and bark beetle attacks, which are already evident in 2023, or extreme droughts.

• Keywords: Forest fires, Slovenia, short-term consequences, regeneration, deadwood