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Iskalni niz: "ključne besede" (growth of a tree) .

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1.
Radial increment of beech (Fagus sylvatica L.) Is under a strong impact of climate in the continental biogeographical region of Croatia
Tom 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: 401; Prenosov: 201
.pdf Celotno besedilo (4,96 MB)
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2.
Tree and stand growth differ among soil classes in semi-natural forests in central Europe
Andrej 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: 545; Prenosov: 259
.pdf Celotno besedilo (2,23 MB)
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3.
Early-warning signals of individual tree mortality based on annual radial growth
Maxime 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: 586; Prenosov: 386
.pdf Celotno besedilo (2,19 MB)
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4.
Growth-limiting factors and climate response variability in Norway spruce (Picea abies L.) along an elevation and precipitation gradients in Slovenia
Jernej Jevšenak, Ivan Tychkov, Jožica Gričar, Tom Levanič, Jan Tumajer, Peter Prislan, Domen Arnič, Margarita Popkova, Vladimir V. Shishov, 2020, izvirni znanstveni članek

Povzetek: Norway spruce (Picea abies L.) is among the most sensitive coniferous species to ongoing climate change. However, previous studies on its growth response to increasing temperatures have yielded contrasting results (from stimulation to suppression), suggesting highly site-specific responses. Here, we present the first study that applies two independent approaches, i.e. the nonlinear, process-based Vaganov-Shashkin (VS) model and linear daily response functions. Data were collected at twelve sites in Slovenia differing in climate regimes and ranging elevation between 170 and 1300 m a.s.l. VS model results revealed that drier Norway spruce sites at lower elevations are mostly moisture limited, while moist high-elevation sites are generally more temperature limited. Daily response functions match well the pattern of growth-limiting factors from the VS model and further explain the effect of climate on radial growth: prevailing growth-limiting factors correspond to the climate variable with higher correlations. Radial growth correlates negatively with rising summer temperature and positively with higher spring precipitation. The opposite response was observed for the wettest site at the highest elevation, which positively reacts to increased summer temperature and will most likely benefit from a warming climate. For all other sites, the future radial growth of Norway spruce largely depends on the balance between spring precipitation and summer temperature.
Ključne besede: Vaganov-Shashkin model, climate-growth correlations, tree rings, process-based modelling, dendroTools, dendroclimatology
Objavljeno v DiRROS: 21.10.2020; Ogledov: 1210; Prenosov: 949
.pdf Celotno besedilo (1,94 MB)
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5.
Daily climate data reveal stronger climate-growth relationships for an extended European tree-ring network
Jernej Jevšenak, 2019, izvirni znanstveni članek

Povzetek: An extended European tree-ring network was compiled from various sources of tree-ring data from Europe, northern Africa and western Asia. A total of 1860 tree-ring chronologies were used to compare correlation coefficients calculated with aggregated day-wise and month-wise mean temperature, sums of precipitation and standardised precipitation-evapotranspiration index (SPEI). For the daily approach, climate data were aggregated over periods ranging from 21 to 365 days. Absolute correlations calculated with day-wise aggregated climate data were on average higher by 0.060 (temperature data), 0.076 (precipitation data) and 0.075 (SPEI data). Bootstrapped correlations are computationally expensive and were therefore calculated on a 69.4% subset of the data. Bootstrapped correlations indicated statistically significant differences between the daily and monthly approach in approximately 1% of examples. A comparison of time windows used for calculations of correlations revealed slightly later onset and earlier ending day of the year for the daily approach, while the largest differences between the two approaches arise from window lengths: Correlations calculated with day-wise aggregated climate data were calculated using fewer days than the monthly approach. Differences in the onset and ending dates of periods for the daily and monthly approaches were greater for precipitation and SPEI data than for temperature data.
Ključne besede: tree rings, dendroclimatology, tree-ring network, daily climate data, climate-growth relationships, dendroTools
Objavljeno v DiRROS: 21.08.2019; Ogledov: 2225; Prenosov: 1019
.pdf Celotno besedilo (889,22 KB)
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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 Slovenia
Kristina 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: 6847; Prenosov: 2911
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7.
O rastnih funkcijah
Anton Cedilnik, 1979, izvirni znanstveni članek

Povzetek: Članek ima namen z matematičnega stališča osvetliti lastnosti funkcij, ki jih gozdarji, agronomi in biologi uporabljajo za opis rasti nekaterih količin, kot višinska, debelinska, prostorninska rast dreves v odvisnosti od časa in podobno. Navadno uporabljajo za ponazoritev teh procesov elementarne, odsekoma analitične funkcije, ker na takih lahko uporabimo metode aproksimacije eksperimentalnih podatkov. Vendar take funkcije le grobo kažejo dejanska dogajanja v majhnih intervalih neodvisne spremenljivke. Zato bi bilo treba postaviti trdnejše temelje in kriterije za določevanje tipov funkcij, ki bi bile primerne za opisovanje katerih koli pojavov te vrste. Ta študija je poskus v tej smeri.
Ključne besede: matematika, gozdarstvo, rastna funkcija, biološka rast, karakteristična funkcija, subjektivni čas, rast drevesa, mathematics, forestry, growth function, biological growth, characteristic function, subjective time, growth of a tree
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4381; Prenosov: 1885
.pdf Celotno besedilo (1,23 MB)

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