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Povzetek: Since the impact of temperature on seedling growth and biomass allocation of different tree species remains relatively unknown, the influence of different temperature conditions on stem diameter (xylem and bark), stem and root extensions, as well as below- and aboveground woody biomass, in three-year old European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.) seedlings in 2010–2011 were studied. One-year-old seedlings were grown outdoors (mean temperature during the growing season = 17–19°C), in the greenhouse (mean temperature during the growing season = 22–24°C) and climatized room (mean temperature during the growing season = 15–17°C) for two years. In terms of radial increment, xylem increments were narrowest in the case of increased temperature for beech and decreased temperature for pine. There was no difference in the thickness of the bark in beech seedlings exposed to different temperature conditions whereas in pine, the bark proportion was highest in control seedlings with the widest diameters. The periderm thickness was comparable in seedlings exposed to different temperatures and represented 10–14 % and 15 % of the bark tissue in pine and beech, respectively. Comparison of the total radial increments of seedlings of the two species under different temperature conditions showed that they were wider in pine in all three regimes. Increment of the main root was considerably higher in both species and represented about 90 % of the total length increment in beech and 74–87 % in pine. In addition, woody biomass was substantially higher aboveground in both tree species (by about 70–80 %). With beech, above- and belowground biomass was reduced in the case of elevated temperature, with the smallest share of roots. In pine, lower temperature diminished amount of biomass and caused its greatest allocation to belowground, which represented almost half of the total biomass accumulation. The short-term treatments clearly show that biomass allocation shifts of pine and beech in response to temperature seem to be a species-specific. The observed differences could be viewed as a plastic adjustment to environmental heterogeneity.
Ključne besede: European beech, Scots pine, radial increment, stem, root, bark, xylem
Objavljeno v DiRROS: 27.01.2026; Ogledov: 206; Prenosov: 96
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Ključne besede: research data, bark beetles
Objavljeno v DiRROS: 30.06.2025; Ogledov: 687; Prenosov: 366
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Ključne besede: small-scale forest owners, natural disturbances, bark beetle, diverging interests, forest-based value chain, forest policy
Objavljeno v DiRROS: 06.10.2023; Ogledov: 1367; Prenosov: 551
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Povzetek: Norway spruce (Picea abies [L.] Karst.) has been at the centre of controversy for many decades. Recent evidence of its profound disturbance-induced damage and consequent stock depletions across forest landscapes in Europe has reinforced doubts regarding the sustainability and prospects of this tree species in the future. Like many other European countries, Slovenia has experienced significant Norway spruce mortality and a decrease in growing stock primarily as the result of several disturbance agents (bark beetle outbreaks, an ice storm, windthrows). We investigated a countrywide spruce growing stock decline based on data between 2010 and 2018. Particular focus was placed on identifying the main ecological drivers of this decline, namely geological conditions, climatic parameters, soil attributes, topographic factors and forest stand characteristics. The effects of potential predictors on the relative change (%) in spruce volume (m3 ha-1) during the period 2010-2018 were analysed with Generalized Additive Models. Based on a national dataset including forest compartments (n = 6355) with a spruce growing stock decline > 10%, we found mixed support for ecology-based hypotheses. While spruce decline responded to bedrock type as predicted (i.e., greater relative decline in carbonate compared to silicate compartments), higher forest naturalness (preservation of tree species composition) was not associated with a lower decline. Spruce decline was amplified by higher potential evapotranspiration and soil clay content but showed a strong negative relationship with spruce proportion in the year 2010. General trends along the gradients of other selected predictors (stoniness/rockiness and heat load index) were less pronounced. The results suggest that most of these ecological predictors interact with geology and forest naturalness in affecting Norway spruce decline. Our analysis reveals that bedrock type can play an important role due to its mitigating effects. However, forest naturalness is of secondary significance as intensified large-scale forest disturbances likely override its buffering potential.
Ključne besede: Norway Spruce, bark beetle outbreaks, ice storm, soil-geology, relationship, tree species composition, Slovenia
Objavljeno v DiRROS: 05.04.2023; Ogledov: 1982; Prenosov: 924
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Povzetek: It is expected that climate change as well as abiotic and anthropogenic disturbances will strongly influence temperate forests. Besides changes in the main climate variables, various disturbance factors may significantly worsen conditions for mesic Slovenian forests (SE Europe) dominated by European beech (Fagus sylvatica), Norway spruce (Picea abies) and European silver fir (Abies alba). In Slovenia, the climate has warmed in recent decades, with an average annual rate of increase of about 0.4°C per decade or even more than 0.5°C per decade in summer. In addition, disturbances have caused considerable damage to trees in the most extensive forest types in Slovenia, starting with a widespread ice storm in 2014, followed by bark beetle outbreaks, windthrows and salvage logging interventions. After 2014, salvage logging increased from about one third to two thirds of the total annual felling. Over the last two decades, we have observed a decline in Norway spruce growing stock, with the highest rate of decrease in areas below 500 m a.s.l., and an increasing trend for European beech. Overall, the three dominant species (beech, spruce, silver fir), which together account for more than 70% of the total growing stock, have shown a declining trend over the last 20 years. The patterns observed are broadly consistent with earlier predictions developed for different climate change scenarios and with those reported in many other European countries. Adaptive forest management, which implements close-to-nature silviculture, has been traditionally practised in the region under study and has the potential to play an important role in reducing the risks associated with the impacts of climate change and disturbances in the future.
Ključne besede: climate warming, disturbance factors, ice storm, bark beetle outbreaks, spruce decline, salvage logging, tree species composition, temperate forest, Slovenia
Objavljeno v DiRROS: 03.01.2022; Ogledov: 1836; Prenosov: 1395
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