1. Radial increment of beech (Fagus sylvatica L.) Is under a strong impact of climate in the continental biogeographical region of CroatiaTom Levanič, Damir Ugarković, Ivan Seletković, Mladen Ognjenović, Mia Marušić, Robert Bogdanić, Nenad Potočić, 2023, izvirni znanstveni članek Povzetek: European beech (Fagus sylvatica L.) is an important component of forests in the alpine and continental biogeographical regions of Croatia. This study aimed to (1) analyze the long-term response of beech to climate, (2) identify potentially critical climatic conditions that could negatively affect the radial increment (RI) and vitality of beech, and (3) evaluate differences in the response of beech between the two biogeographical regions in Croatia. We used the 16 × 16 km Croatian ICP Forests Level 1 network. On a total of 25 plots, we cored between 5 and 24 trees for dendrochronological analysis. Tree-ring widths (TRW) were measured and standardized using cubic spline. TRW chronologies for the two regions were calculated and correlated to the temperature and precipitation data and Standardized Precipitation and Evapotranspiration Index (SPEI) using bootstrapped correlations. Continental region precipitation from April to August and alpine region precipitation from June to August were significantly important for RI. Temperature was less important for RI than precipitation in both regions, but the importance of the negative impact of above-average temperatures in the continental region and the positive impact of above-average precipitation in the alpine region has increased over the last two decades. A comparison with the 3-month SPEI confirmed the significant influence of high temperatures and the lack of precipitation in August on the RI of beech trees in both regions.
Ključne besede: climate change, tree growth, forest productivity, drought, European beech
Objavljeno v DiRROS: 28.06.2023; Ogledov: 424; Prenosov: 212
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2. Tree and stand growth differ among soil classes in semi-natural forests in central EuropeAndrej Bončina, Matija Klopčič, Vasilije Trifković, Andrej Ficko, Primož Simončič, 2023, izvirni znanstveni članek Povzetek: We determined the size of differences in stand and tree growth in semi-natural forests with respect to 16 reference soil groups. The forest area of Slovenia (11.8 thousand km2) was used as the study area, and reference soil units were derived from the national soil map at a 1:25,000 scale consisting of 10,781 polygons with an average size of 117.95 ha. Stand growth was defined as periodic stand basal area increment, while the growth of Norway spruce, silver fir, Scots pine, European beech and sessile oak trees was estimated by the periodic diameter increment of 238,349 dominant trees on 67,061 permanent sampling plots. A linear fixed-effects model and linear mixed-effect models were used for studying stand and tree growth in different site, stand and tree conditions. The soil unit was the dummy variable with Dystric Cambisols set as the reference category. Soil contributed 4.3 % to the explained variability of basal area increment and 4–27 % to the explained variability of the diameter increment of the five tree species. Soil was a stronger driver of stand and tree growth than climate or topography. Stand and tree species production rate on soil units was in the interval of −28 % to +5 % and −47 % to +14 % of that on the reference soil unit, respectively. Stand growth was the highest on Eutric Gleysols and the lowest on Histosols, and tree species generally exhibited the highest and the lowest growth rates on different soil units. We suggest that soil should be considered in growth models and studied interrelatedly with climatic, site and stand variables.
Ključne besede: reference soil groups, FAO soil unit, natural forest, stand growth, tree growth
Objavljeno v DiRROS: 29.12.2022; Ogledov: 563; Prenosov: 275
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3. Early-warning signals of individual tree mortality based on annual radial growthMaxime Cailleret, Vasilis Dakos, Steven Jansen, Elisabeth M.R. Robert, Tuomas Aakala, Mariano M. Amoroso, Joe A. Antos, Christof Bigler, Harald Bugmann, Marco Caccianaga, Katarina Čufar, Tom Levanič, 2019, izvirni znanstveni članek Povzetek: Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the differences in growth level between trees that died and survived a given mortality event to assess whether changes in temporal autocorrelation, variance, and synchrony in time-series of annual radial growth data can be used as early warning signals of mortality risk. Taking advantage of a unique global ring-width database of 3065 dead trees and 4389 living trees growing together at 198 sites (belonging to 36 gymnosperm and angiosperm species), we analyzed temporal changes in autocorrelation, variance, and synchrony before tree death (diachronic analysis), and also compared these metrics between trees that died and trees that survived a given mortality event (synchronic analysis). Changes in autocorrelation were a poor indicator of mortality risk. However, we found a gradual increase in interannual growth variability and a decrease in growth synchrony in the last %20 years before mortality of gymnosperms, irrespective of the cause of mortality. These changes could be associated with drought-induced alterations in carbon economy and allocation patterns. In angiosperms, we did not find any consistent changes in any metric. Such lack of any signal might be explained by the relatively high capacity of angiosperms to recover after a stress-induced growth decline. Our analysis provides a robust method for estimating early-warning signals of tree mortality based on annual growth data. In addition to the frequently reported decrease in growth rates, an increase in inter-annual growth variability and a decrease in growth synchrony may be powerful predictors of gymnosperm mortality risk, but not necessarily so for angiosperms.
Ključne besede: tree mortality, ring-width, forest, growth, resilience indicators, drought, biotic agents, variance
Objavljeno v DiRROS: 20.07.2022; Ogledov: 610; Prenosov: 395
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4. Buckwheat milling waste effects on root morphology and mycorrhization of Silver fir seedlings inoculated with Black Summer Truffle (Tuber aestivum Vittad.)Tina Unuk Nahberger, Tine Grebenc, Daniel Žlindra, Tanja Mrak, Matevž Likar, Hojka Kraigher, Zlata Luthar, 2022, izvirni znanstveni članek Povzetek: Large amounts of buckwheat waste are generated annually by the industry and are used in several different ways. To date, there has been little research regarding its suitability as a medium for growing seedlings in nurseries. The aim of this study was therefore to analyze the suitability of common and Tartary buckwheat wastes (brans and husks) as media used for raising seedlings. A pot experiment with five different treatments was carried out, in which silver fir root parameters were analyzed and compared 6 and 12 months after summer truffle-spore inoculation. A significantly higher concentration of the antioxidant rutin was confirmed in Tartary buckwheat bran compared to other buckwheat waste used. We also confirmed a significantly positive effect of added Tartary buckwheat husks on specific root length, root tip density, and specific root tip density compared to added common buckwheat husks or Tartary buckwheat bran, for which a significantly negative effect on branching density was confirmed. A significantly negative effect of added buckwheat husks and Tartary buckwheat bran was confirmed for summer truffle mycorrhization level.
Ključne besede: buckwheat waste, root growth, summer truffle, forest nursery, silver fir, inoculation with ectomycorrhizal fungi
Objavljeno v DiRROS: 09.02.2022; Ogledov: 914; Prenosov: 619
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5. Water regulation ecosystem services following gap formation in Fir-beech forests in the Dinaric KarstUrša Vilhar, 2021, izvirni znanstveni članek Povzetek: This paper investigates how variation in forest structural characteristics affects the water retention capacity of gaps and forests in fir-beech forests in the Dinaric Karst. Forests are identified as a key element of the landscape for provision of pristine water resources, particularly in highly vulnerable karst aquifers characterized by rapid infiltration of recharge water, high subsurface permeability, and heterogeneous underground flow. Indicators of hydrologic fluxes (drainage flux, canopy interception, transpiration, and soil evaporation) in a large experimental gap (approximately 0.2 ha in size) and those in a nearby old-growth gap were compared over a 13-year period using the Brook90 hydrological model and their structural characteristics were analyzed. In addition, the hydrologic fluxes were also simulated for a managed forest and an old-growth forest for reference. Water regulation capacity was lowest in the experimental gap, where drainage flux accounted for 81% of precipitation and the sum of canopy interception, transpiration, and soil evaporation (evapotranspiration) accounted for 18%. This was followed by the old-growth gap, where drainage flux accounted for 78% of precipitation and evapotranspiration for 23%. Water retention capacity was highest and generally similar for both forests, where 71%72% of annual precipitation drained to the subsurface. The results of this study suggest that the creation of large canopy gaps in fir-beech forests in the Dinaric Karst results in significant and long-lasting reduction in soil and vegetation water retention capacity due to unfavorable conditions for successful natural tree regeneration. For optimal provision of water regulation ecosystem services of forests in the Dinaric Karst, small, irregularly shaped canopy gaps no larger than tree height should be created, mimicking the structural characteristics of naturally occurring gaps in old-growth forests.
Ključne besede: water retention capacity, drainage flux, evapotranspiration, Brook90 hydrological model, experimental canopy gap, old-growth forest
Objavljeno v DiRROS: 05.03.2021; Ogledov: 986; Prenosov: 819
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6. Patterns of tree microhabitats across a gradient of managed to old-growth conditions : a case study from beech dominated forests of South-Eastern SloveniaKristina Sever, Thomas Andrew Nagel, 2019, izvirni znanstveni članek Povzetek: An inventory of tree microhabitats was done in two unmanaged forests (Kobile and Ravna gora forest reserves) and one managed beech forest in SE Slovenia. The purpose of this study was to determine the influence of forest management, natural disturbances, and tree characteristics on microhabitat patterns. Forest structure and microhabitats were recorded in systematically placed plots (500 m2 in size) across each area. In total, we inventoried 849 trees on 54 plots and 1833 tree microhabitats. The results showed that forest management had no significant influence on the abundance of microhabitats per tree, but there were differences regarding microhabitat type between managed and unmanaged sites. There were substantially more microhabitats related to standing dead and live habitat trees in unmanaged forest (e.g. woodpecker cavities, insect galleries and bore holes, branch holes, dead branches and fruiting bodies of fungi), whereas in managed forests there were more tree microhabitats related to management (e.g. exposed heartwood, coarse bark, and epiphytic plants). The results also indicate that disturbance, tree diameter, vitality, and species influence the density, diversity, and occurrence of tree microhabitats.
Ključne besede: forest management, biodiversity, tree microhabitats, beech forests, old-growth, veteran tree, natural disturbance, dead wood
Objavljeno v DiRROS: 08.07.2019; Ogledov: 6912; Prenosov: 2928
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7. Influence of moisture, temperature and growth medium on Cenangium dieback of pine (Cenangium ferruginosum Fr., Ascomycotina)Dušan Jurc, Maja Jurc, 1997, izvirni znanstveni članek Ključne besede: Cenangium dieback of pines, forest dieback, fungi, Cenangium ferruginosum Fr., temperature, moisture, growth medium
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4294; Prenosov: 1851
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