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Query: "author" (Mitja Ferlan) .

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21.
Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescens
Jožica Gričar, Polona Hafner, Martina Lavrič, Mitja Ferlan, Nives Ogrinc, Bor Krajnc, Klemen Eler, Dominik Vodnik, 2020, original scientific article

Abstract: An increased frequency of fire events on the Slovenian Karst is in line with future climate-change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (%13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Q. pubescens with good re-sprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the LAI values measured in H-trees. Throughout the season, F-trees were characterised by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative %13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3 weeks later in F-trees, resulting in 60% and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem anatomy in the analyses revealed that fire caused changes in conduit dimensions in the early phloem but not in the earlywood. However, premature formation of the tyloses in the earlywood vessels of the youngest two xylem increments in F-trees implies that xylem hydraulic integrity was also affected by heat. Analyses of secondary tissues showed that although xylem and phloem tissues are interlinked changes in their transport systems due to heat damage are not necessarily coordinated.
Keywords: pubescent oak, cambium, radial growth, xylem, phloem, anatomy, sub-Mediterranean
Published in DiRROS: 19.03.2020; Views: 2377; Downloads: 1270
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22.
Measuring techniques for concentration and stable isotopologues of CO2 in a terrestrial ecosystem : a review
Grega E. Voglar, Saša Zavadlav, Tom Levanič, Mitja Ferlan, 2019, review article

Abstract: Measurements of carbon dioxide and their stable isotopes are propulsive research tool in ecology and environmental science as they can give us insight into carbon cycle. They are widely used to investigate both natural and anthropogenic carbon sources in the atmosphere, hydrosphere and geosphere, as well as the exchange between these reservoirs. In this paper, we provide a basic overview of two different analytical measurement techniques, isotope ratio mass spectrometry (IRMS) and laser-absorption spectroscopy (LAS) which have been developed and utilized for monitoring of CO2 isotopologues in ecosystem. We present the basics for each technique, however with the emphasis on LAS measurement technique we are targeting readers who are not familiar with this topic. A major objective of this paper is to illustrate the current value and future potential of various analytical instruments in a wide range of applications deployed in the terrestrial ecosystem. Finally, we draw a conclusion from recent research campaigns by presenting a decision tree to better understand and choose a correct application combination for a selected scale of ecosystem.
Keywords: Isotope ratio mass spectrometry, laser-absorption spectroscopy, CO2 isotopologues, terrestrial ecosystem, decision tree, spectroscopic databases
Published in DiRROS: 18.02.2020; Views: 1724; Downloads: 757
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23.
Mikroklimatske razmere v sestojih in vrzelih dinarskih jelovobukovih gozdov Slovenije z vidika podnebnih sprememb
Janez Kermavnar, Mitja Ferlan, Aleksander Marinšek, Klemen Eler, Andrej Kobler, Lado Kutnar, 2019, original scientific article

Abstract: Dinarski jelovo-bukovi gozdovi so eden glavnih gozdnih vegetacijskih tipov v Sloveniji, v katerih so se v zadnjem obdobju zaradi naravnih ujm spremenile ekološke razmere. Namen raziskave je bila analiza izbranih spremenljivk mikroklime (temperatura zraka, relativna zračna vlaga) v strnjenih sestojih, v presvetljenih sestojih in v sestojnih vrzelih na treh raziskovalnih območjih (Trnovski gozd, Snežnik, Kočevski rog). Za strnjene sestoje je bila značilna visoka stopnja zastiranja tal s krošnjami dreves ( ~ 95 %). Sestojne vrzeli so nastale s posekom vseh dreves na krožni površini 0,4 ha, v presvetljenih sestojih pa je bila posekana približno polovica lesne zaloge gozdnega sestoja. Ukrepi so bili izvedeni leta 2012, meritve meteoroloških spremenljivk pa smo opravili prvo (2013) in drugo (2014) leto po sečnji. Primerjali smo, kako se mikroklimatske razmere v sestojih in vrzelih spreminjajo v vegetacijski sezoni (maj-oktober) in kakšne so razlike med dvema meteorološko razmeroma različnima poletjema v letih 2013 (več vročinskih valov, poletna suša) in 2014 (nestanovitno vreme z relativno veliko količino padavin). Izmerjene najvišje dnevne temperature zraka (Tmax) so bile izrazito višje v vrzelih kot v sestoju, v povprečju za 3,6 °C; najnižja relativna zračna vlaga (RVmin) pa je bila nižja, v povprečju za 15,0 odstotnih točk. Razlike v obeh spremenljivkah med sestoji in vrzelmi so bile največje v poletnih mesecih (junij-avgust) leta 2013 (Tmax: 4,9 °C; RVmin: -19,7 odstotnih točk), ki je bilo razmeroma vroče in sušno. Na podlagi meritev meteoroloških spremenljivk in zastora drevesnih krošenj (podatki LiDARskega snemanja) v presvetljenih sestojih smo ugotovili statistično značilno negativno linearno povezavo med zastorom drevesnih krošenj in Tmax ter pozitivno povezavo med zastorom krošenj in vrednostmi RVmin. Rezultate analiz smo prikazali v luči potencialnih vplivov podnebnih sprememb, katerim so dinarski jelovo-bukovi gozdovi zaradi kombinacije neugodnih dejavnikov npr. zmanjšana mehanska in biološka stabilnost sestojev zaradi velikopovršinskih motenj, poletne suše, vodoprepusten kraški teren ter pogosto plitva tla z majhno sposobnostjo zadrževanja vode - še posebej izpostavljeni.
Keywords: dinarski jelovo-bukovi gozdovi, temperatura zraka, relativna zračna vlaga, sestojne vrzeli, zastor krošenj dreves, podnebne spremembe, Slovenija
Published in DiRROS: 20.12.2019; Views: 2536; Downloads: 771
.pdf Full text (388,92 KB)

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Influence of meteorological conditions and crown defoliation on tree phenology in intensive forest monitoring plots in Slovenia
Urša Vilhar, Mitja Skudnik, Mitja Ferlan, Primož Simončič, 2014, original scientific article

Abstract: Data from the forest monitoring programme in Slovenia were used to assess the relationship between tree phenology, crown defoliation and meteorological conditions in Fagus sylvatica, Quercus robur and Picea abies forests in the 2004-2013 period. We hypothesized a species-specific response of first leaf unfolding, general leaf colouring, the length of the growing season to crown defoliation, air temperature, precipitation and soil water. In accordance with the hypothesis, we found a high sensitivity of first leaf unfolding to air temperature and precipitation for all species, exhibiting contrasting responses. We observed strong sensitivity of beech defoliation to precipitation and soil water conditions. Oak crown defoliation and next-year phenology were correlated, with higher crown defoliation contributing to earlier leaf unfolding, later autumn leaf colouring and longer growing season of oak in next year. Correlation between crown defoliation and phenology was found neither for beech nor spruce.
Published in DiRROS: 12.07.2017; Views: 4318; Downloads: 2316
.pdf Full text (1,35 MB)

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