1. |
2. Recommendations for assessing xylogenesis in angiosperm treesLorène Julia Marchand, Peter Prislan, Jožica Gričar, Cristina Nabais, Elena Larysch, Roberto Silvestro, Omar Flores, Cyrille Rathgeber, Patrick Fonti, 2026, izvirni znanstveni članek Povzetek: Understanding wood formation is critical for interpreting tree growth and carbon allocation under changing environmental conditions. While major progress has been made for gymnosperms, harmonized approaches for studying xylogenesis in angiosperms remain limited. Here, we present practical recommendations for observing and analysing xylogenesis in angiosperm trees, illustrated from examples from temperate and sub-Mediterranean forests. The perspective includes guidance on identifying xylem cell types in histological sections, defining developmental phenophases and establishing a workflow for data collection (and analysis). Annotated images are provided to support reproducibility and inter-observer consistency. We also discuss key challenges unique to angiosperms, including cell-type-specificities and wood type differences. Future research priorities include conserving histological images, extending xylogenesis to branches and coarse roots, enabling cross-biome comparisons and advancing kinetic analysis. This framework supports the coordinated expansion of angiosperm xylogenesis studies, enabling deeper insights into tree functioning in a changing world.
Ključne besede: wood formation, xylem cell types, wood type, methodology
Objavljeno v DiRROS: 19.02.2026; Ogledov: 440; Prenosov: 202
 Celotno besedilo (46,72 MB)
Gradivo ima več datotek! Več... |
3. Temperature and photoperiod interactions influence the cessation of wood growth in three temperate and boreal conifersJianhong Lin, Cyrille Rathgeber, Patrick Fonti, Sergio Rossi, Henri E. Cuny, Edurne Martinez Del Castillo, Katarina Čufar, Jesús J. Camarero, Alessio Giovannelli, Harri Mäkinen, Peter Prislan, Walter Oberhuber, Hanuš Vavrčík, Jianguo Huang, Andreas Gruber, Vladimir Gryc, Václav Treml, Martin De Luis, Jožica Gričar, Nicolas Delpierre, 2026, izvirni znanstveni članek Povzetek: Cambium phenology is a crucial process in wood production and carbon sequestration of forest ecosystems. Although cambium phenology has been widely studied, research specifically focusing on the cessation of wood formation remains limited. To better understand the influence of environmental and intrinsic factors on the cessation of wood formation, we built and compared three ecophysiological models (temperature sum model, photoperiod-influenced temperature sum model and soil moisture- and photoperiod-influenced temperature sum model) in their ability to predict the date of cessation of xylem cell enlargement (cE) in three major Northern Hemisphere conifer species (Black spruce, Norway spruce and Scots pine). We developed these models based on xylogenesis data collected for 130 site‐years across Europe and Canada. Our results demonstrate that the photoperiod-influenced temperature sum model is well-supported by data across all conifer species, with a RMSE of 9.2 days, suggesting that both temperature and photoperiod are critical drivers of wood growth cessation. However, incorporating soil moisture effects does not improve model performance. Our model effectively captures the inter-site variability in cE across a wide environmental gradient, with a fair model efficiency (ME = 0.51 ± 0.22), but performed less well for annual anomalies (ME = 0.10 ± 0.09). Additionally, we found that the total ring cell number also affected prediction accuracy. Using this model, we reconstructed historical trends in cE over the past six decades and found a trend to delayed cessation dates. This delay varied geographically, with slower shifts at higher latitudes and elevations, likely due to constrained cambial responses and conservative growth strategies in colder regions. Our model framework offers a simple yet accurate approach for predicting wood growth cessation at large spatial scales, providing a basis for integrating cambium phenology into land surface models and forest productivity assessments.
Ključne besede: cambium phenology, ecophysiological models, xylem formation, climate change, global warming, northern hemisphere forests
Objavljeno v DiRROS: 12.02.2026; Ogledov: 534; Prenosov: 230
Celotno besedilo (1,76 MB)
Gradivo ima več datotek! Več... |
4. Year-to-year variability in xylem and phloem traits of co-existing Fraxinus ornus, Quercus pubescens and Ostrya carpinifoliaJožica Gričar, Klemen Eler, Saša Ogorevc, Debojit Chanda, Sarkiri Kro, Mohendra Thapa, Polona Hafner, Peter Prislan, 2026, izvirni znanstveni članek Povzetek: The xylem and phloem anatomy of co-existing tree species provides valuable information on how different tree species face climate change and adjust their vascular structure to local weather conditions. We examined and compared annual ring widths and conduit size in earlywood and early phloem in Fraxinus ornus, Quercus pubescens and Ostrya carpinifolia in a sub-Mediterranean site in the period 2019–2021. The selected xylem and phloem traits were correlated with monthly weather conditions (precipitation and temperature). We found that phloem increment widths and conduits in earlywood and early phloem in the studied tree species showed different trends in terms of interannual variability and in relation to local weather conditions. In F. ornus, May conditions affected xylem traits, while June conditions phloem traits. In Q. pubescens, winter and March precipitation was related to phloem development. In O. carpinifolia, xylem ring width was positively correlated with June precipitation, while early phloem conduits were negatively affected by April temperature. Only two consistent patterns were detected across the species and years studied: wider xylem increments compared to phloem increments, and wider earlywood vessels compared to early phloem sieve tubes. Statistically significant differences were observed among species across all years for the size of xylem and phloem conduits and the hydraulic conductivity of earlywood vessels, which indicates great differences in the calculated hydraulic conductivity among the tree species. To summarize, hydraulic conductivity of earlywood vessels in Q. pubescens was on average for all three years 10.4 -times and 114-times larger than in F. ornus and O. carpinifolia, respectively. High interannual variability and species-specific sensitivity of xylem and phloem traits to precipitation and temperature confirm high plasticity and different radial growth strategies of the studied tree species to ensure optimal functioning under local weather conditions.
Ključne besede: manna ash, pubescent oak, European hop-hornbeam, earlywood, early phloem, wood anatomy, sub-Mediterranean
Objavljeno v DiRROS: 12.02.2026; Ogledov: 617; Prenosov: 248
Celotno besedilo (1,65 MB)
Gradivo ima več datotek! Več... |
5. |
6. Soil nitrogen drives inverse acclimation of xylem growth cessation to rising temperature in Northern Hemisphere conifersYaling Zhang, Jian-Guo Huang, Minhuang Wang, Wenjin Wang, Annie Deslauriers, Patrick Fonti, Eryuan Liang, Katarina Čufar, Jožica Gričar, Peter Prislan, 2025, izvirni znanstveni članek Povzetek: Controlled experiments suggest that the seasonal build-up of nitrogen (N) limitation constrains the responses of forest autumn phenology to elevated temperatures. Therefore, rising soil N is expected to increase the delaying effects of elevated temperature on the end of the season, i.e., leaf senescence. However, the interactive effects of temperature, soil N, and aridity on xylem autumn phenology remain unknown. We conducted a wide spatial analysis from 75 conifer sites in the Northern Hemisphere and found that rising soil N increases the delaying effects of elevated temperature on the end of xylem cell wall thickening but reduced the delaying effects on the cessation of cell enlargement, especially in humid regions. The contrasting effects of elevated soil N on cell enlargement versus cell wall thickening could affect xylem cell anatomy, thereby induce changes in wood density, and induce a decoupling of stem size growth from photosynthate production. These analyses extend previous findings on forest autumn phenology by systematically investigating the spatial variation in the interactive effects of temperature and soil N on xylem autumn phenology at the cellular scale.
Ključne besede: soil moisture, stem growth, autumn phenology, wood formation, xylogenesis
Objavljeno v DiRROS: 21.01.2026; Ogledov: 304; Prenosov: 233
Celotno besedilo (1,14 MB)
Gradivo ima več datotek! Več... |
7. Dataset of xylem and phloem traits of Fraxinus ornus, Quercus pubescens and Ostrya carpinifolia from Podgorski Kras (Slovenia) in the period 2019-2021Jožica Gričar, Klemen Eler, Saša Ogorevc, Debojit Chanda, Sarkiri Kro, Mohendra Thapa, Polona Hafner, Peter Prislan, 2025, zaključena znanstvena zbirka raziskovalnih podatkov Ključne besede: raziskovalni podatki
Objavljeno v DiRROS: 28.11.2025; Ogledov: 866; Prenosov: 489
 Celotno besedilo (177,04 KB)
Gradivo ima več datotek! Več... |
8. |
9. Xylem growth cessation in stems and branches of European beech and silver birch : influences of temperature and droughtLorène Julia Marchand, Jožica Gričar, Peter Prislan, Inge Dox, Melanie S. Verlinden, Omar Flores, Matteo Campioli, 2025, izvirni znanstveni članek Povzetek: Introduction: Assessing wood growth phenology over multiple years is essential for understanding the environmental drivers of forest growth and improving large-scale predictions of the carbon cycle. Xylogenesis methods facilitate the assessment of the timing and rate of xylem cell wall thickening, the primary sink of carbon in wood. In angiosperm trees, where wood anatomy is complex, significantly less is known about the factors controlling growth cessation in autumn due to indirect, sinteracting, and lag effects, in contrast to growth resumption in spring. Furthermore, both branch and stem growth must be considered to account for the total aboveground phenology. Methods: In this study, we focused on European beech (Fagus sylvatica) and silver birch (Betula pendula) in a mild temperate region (Northern Belgium). We examined the progress of cell wall thickening in autumn and the seasonal timing of xylem growth cessation for these species’ stems over five years and for their branches over one year in mature trees. In addition, we investigated the same variables in the stems and branches of potted saplings for two years and for oak (Quercus robur) and aspen (Populus tremula) saplings over one year. Results: Our results demonstrate a considerable variation in the progression and cessation of wood growth, with differences of up to a month and a half in growth cessation (early September to late October), predominantly driven by climatic variables. Early cessation of xylem growth in stems was strongly associated with high temperatures in April and August, elevated vapour pressure deficit, and severe soil drought in August. The progression of cell wall thickening in late summer was generally synchronized between branches and stems for every species. However, branches sustained a higher percentage of growth (approximately 2 weeks) in early autumn during non-drought years. Discussion: These findings provide valuable insights for refining models of forest growth and carbon storage, enabling a more comprehensive representation that encompasses the entire tree under different climatic scenarios.
Ključne besede: phenology, cambium, cell wall thickening, hardwood species, atmospheric drought
Objavljeno v DiRROS: 08.09.2025; Ogledov: 562; Prenosov: 359
Celotno besedilo (2,51 MB)
Gradivo ima več datotek! Več... |
10. Tree-ring formation dynamics in Fagus sylvatica and Quercus petraea in a dry and a wet yearRadosław Puchałka, Peter Prislan, Marcin Miroslav Klisz, M. Koprowski, Jožica Gričar, 2024, izvirni znanstveni članek Povzetek: European beech Fagus sylvatica and Sessile oak Quercus petraea are reaching the north-eastern limits of their natural ranges in northern Poland. According to the projected changes in potential ranges in this region, climatic conditions for both species until 2080 will remain stable. On the other hand, a decrease in the vitality of mature trees and a reduction in their radial growth are currently observed. To understand these contradictory findings, we monitored the cambial activity in both species during two vegetation seasons. 2015 was characterized by a negative water balance, while 2017 was wet. This provided an opportunity to compare how the xylogenesis proceeds in diffuse-porous beech and ring-porous oak during contrasting in the summer precipitation seasons. The forming annual increments were sampled with Presler borer at variable time intervals depending on the leaf phenological phases. The cores were prepared using a sledge microtome and double-stained with safranin and astra blue. Observations of the phases of wood formation and measurements of the width of the forming increments were analysed on the microslide digital images. Differences in the dates of the phenological phases were analysed using Two-Way ANOVA, while the dynamics of the formation of annual increments were fitted to the Single and Double Gompertz function for beech and oak, respectively. The beginning of vessel formation started earlier in both seasons compared to previous studies. Inter-seasonal differences in the duration of spring phenological phases were insignificant for both species, while inter-species differences were significant due to physiological diversity between diffuse-porous beech and ring-porous oak. In dry 2015, cambial activity ceased sooner in both species than in 2017. Differences between oak and beech were insignificant in both years, but statistically significant disparities existed within each species due to varying in precipitation seasons. Rainfall significantly elongated the duration of cambial activity and caused wider tree-rings. According to our study, despite predicted maintaining their climatic niche, both species, situated at the north-eastern cooler range boundary, are expected to produce wood at a lower rate due to the projected warmer central European climate with increased heatwaves and summer droughts.
Ključne besede: climate change, meteorological extremes, wood formation, summer drought, xylogenesis
Objavljeno v DiRROS: 08.07.2025; Ogledov: 657; Prenosov: 562
Celotno besedilo (2,56 MB)
Gradivo ima več datotek! Več... |
