Morphological traits of Scots pine (Pinus sylvestris L.) in international provenance tests in Bosnia and HerzegovinaMirzeta Memišević Hodžić
, Semir Bejtić
, Selma Vejzagić
, Dalibor Ballian
Povzetek: Scots pine (Pinus sylvestris L.) is one of the most important tree species in European forests. This study aims to determine whether there is inter-provenance variability in researched morphological traits in two international provenance tests of Scots pine in Bosnia and Herzegovina. We measured height, root collar diameter, and latest shoot length and counted branches on the latest branch whorl of Scots pine plants in two provenance tests. The provenance tests are located in Kupres and Žepče, in different climatic, edaphic, and orographic conditions. Kupres and Žepče contain 15 and 14 provenances, respectively, eleven of which are mutual to both sites. Descriptive statistics and analysis of variance showed differences among provenances in all investigated morphological traits. These differences were attributable to provenance test, provenance, and interaction between provenance test and provenance. The average values were higher in Žepče for all provenances and all studied traits. The Austria A1, Austria A2, Austria A3, and Poland P1 provenances showed the best growth in both tests, while the Italy I1 provenance showed good growth in Žepče but not in Kupres.
Ključne besede: Scots pine, provenance tests, morphological traits, Pinus sylvestris L.
DiRROS - Objavljeno: 01.04.2020; Ogledov: 9; Prenosov: 57
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Tehnična in estetska življenjska doba lesaDavor Kržišnik
, Boštjan Lesar
, Miha Humar
Povzetek: Les na prostem je izpostavljen delovanju biotskih in abiotskih dejavnikov razkroja. V naravi so ti procesi zaželeni, kadar pa les uporabljamo v komercialne namene, želimo razkroj čim bolj upočasniti. V primeru razvrednotenja lesa pa moramo lesene elemente zamenjati. Lesene izdelke praviloma menjamo zaradi estetskih razlogov ali nedoseganja tehničnih zahtev. V tem prispevku opisujemo najpomembnejše mehanizme in razloge za razgradnjo lesa na prostem, naravno odpornost lesa in sodobne rešitve za zaščito. Na koncu so predstavljeni ključni rezultati o obnašanju lesa na terasi lesenega modelnega objekta na Oddelku za lesarstvo. Terasa ponazarja podobno izpostavitev kot mostovi, pohodne površine oziroma streha, zato je primerna kot odličen prikaz obnašanja lesa na prostem.
Ključne besede: les, odpornost lesa, življenjska doba lesa, razkroj, barvne spremembe, lesne glive
DiRROS - Objavljeno: 01.04.2020; Ogledov: 14; Prenosov: 86
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Reconstruction of rockfall activity through dendrogeomorphology and a scar-counting approach : a study in a beech forest stand in the Trenta valley (Slovenian Alps)Barbara Žabota
, Daniel Trappmann
, Tom Levanič
, Milan Kobal
Povzetek: Trees represent an important archive that can be used to reconstruct the spatial and temporal patterns of rockfall events. Rockfall impacts can be recorded in the form of anomalies in tree rings and impact scars on the tree stem. In this paper we demonstrate the use of an approach based on counting scars for reconstructing the frequency and spatial pattern of past rockfalls. The approach was applied by counting the visible scars on the stem surface of 52 European beech trees (Fagus sylvatica L.) in the area of the Trenta Valley, Slovenia. The average number of impacts per trees was 7, and the impacts were mostly classified as old, indicating reduced rockfall activity in recent years. The average recurrence interval was 31.8 years, which was reduced by 1.2 years by the application of the conditional impact probability. The spatial pattern of rockfall impacts shows that rockfall activity is higher in the middle part of the studied slope.
Ključne besede: rockfall, natural hazards, dendrogeomorphology, tree rings, stem scars, recurrence interval
DiRROS - Objavljeno: 01.04.2020; Ogledov: 8; Prenosov: 64
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The influence of abiotic and biotic disturbances on the protective effect of alpine forests against avalanches and rockfallsDomen Oven
, Barbara Žabota
, Milan Kobal
Povzetek: Abiotic and biotic disturbances in alpine forests can reduce forest cover or change the structure of the forest and consequently reduce the protective effect of forest against natural hazards such as avalanches and rockfalls. In this review article, the effect of the main abiotic (forest fire, windthrow, ice break, snow break, avalanche and rockfall) and biotic (insects and pathogens) disturbances in protection forests are presented along with their potential influence on the protective effect of forest against avalanches and rockfalls. In general, natural disturbances negatively affect the protective effect of forest, especially in the case of large-scale and severe events, which in alpine areas are mostly caused by storms, bark beetle outbreaks, avalanches and forest fires. Climate change induced interactions between disturbances are expected to present challenges in the management of protection forests in the future.
Ključne besede: natural disturbances, natural hazards, abiotic disturbances, biotic disturbances, protection forests, protective effect, stand parameters, rockfall, avalanche
DiRROS - Objavljeno: 01.04.2020; Ogledov: 9; Prenosov: 110
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Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescensJožica Gričar
, Polona Hafner
, Martina Lavrič
, Mitja Ferlan
, Nives Ogrinc
, Bor Krajnc
, Klemen Eler
, Dominik Vodnik
Povzetek: 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.
Ključne besede: pubescent oak, cambium, radial growth, xylem, phloem, anatomy, sub-Mediterranean
DiRROS - Objavljeno: 19.03.2020; Ogledov: 48; Prenosov: 19
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