Introduction The yellow azalea (Rhododendron luteum Sweet) is a relict species with a distinct distribution. The lowland populations are primarily located in Ukraine, specifically in Zhytomyr Polissia region. The aim of this study was to investigate the key ecological and silvicultural characteristics of Rh. luteum habitats in moist relatively fertile forest sites and to evaluate the success of regeneration of forest coenoses with undergrowth of this species following clear-cutting in the region. Materials and Methods The study was conducted primarily in 2024. Data on Rh. luteum undergrowth regeneration were derived from field observations in Korosten district, Zhytomyr region. To assess the regeneration dynamics of Rh. luteum undergrowth, 30 experimental plots, each of 0.5–1 ha, were established in different forest age groups, including: mature maternal forests (130–140 years old), young forest plantations (before crown closure): 0–1 year and 4–7 years old; forest plantations after crown closure – 8–10, 11–20, 21–30, 31–40, 41–50, 51–60, 61–70 years old. Within each experimental plot, assessments were conducted to evaluate the development of the floristic composition, coenotic structure, and condition of the Rh. luteum undergrowth. Results The total area of forests with Rh. luteum undergrowth in the moist relatively fertile pine site type (C3) in two forestry enterprises amounts to 2,614.4 ha. Of this total, 88.2% consists of forests of natural origin, while only 11.8% comprises forest plantations. Quercus robur dominates in 53.5 % of the studied stands, and the remaining 46.5 % of the area is represented by secondary stands. Within these, Betula pendula occupies 28.6 %, Pinus sylvestris 14.4 %, Populus tremula 2.1 %, and Alnus glutinosa 1.5 %. The largest proportion of the studied forests belongs to the 71–80-year age group (29.2%) and the 61–70-year age group (26.8%). It was shown that in stands older than 40 years, the forest coenosis reached a fully developed state, characterised by a typical floristic composition and coenotic structure. The Rh. luteum undergrowth exhibited a projective cover of approximately 45% at 41 years, increasing to 60–70% at 58 years and 80–90 % at 66 years. The species displayed high vitality, even distribution, and mass flowering. These findings indicate that after clear-cutting Rh. luteum undergrowth regenerates satisfactorily within 40 years. By the 60–70-year age group, the development of a closed Rh. luteum undergrowth is nearly complete, and the physiognomy of the coenosis closely resembles that of the original (maternal) stands. Conclusions Following clear-cutting, Rh. luteum undergrowth regenerates satisfactorily within 40 years in those forests. However, in 17% of surveyed plots, Rh. luteum failed to regenerate, primarily due to excessive stand density, as well as untimely and insufficient thinning in stands under 30 years old. In the Branch “Luhyny Forestry” of the SFE “Forests of Ukraine”, the area of forest stands with Rh. luteum-dominated undergrowth in moist relatively fertile pine sites (C3) declined by 2.2 times between 1978 and 2018, from 926.0 ha to 423.8 ha. 10 Figs., 2 Tables, 30 Refs.

The effect of clear-cut age on soil organic carbon and nitrogen indices in Scots pine (Pinus sylvestris L.) stands

Xylogenesis – the process of secondary xylem formation – is tightly regulated by hormonal, physiological, and environmental signals, but becomes highly vulnerable under extreme climatic stress. Drought, heatwaves, and late frosts can disrupt key stages of cambial activity, cell production, differentiation, and maturation, leading to the formation of distinct anatomical anomalies in the wood of individual tree rings. We present examples of wood anatomical features collected during xylogenesis experiments in (1) Mediterranean and semi-arid, (2) arid and semi-arid, as well as (3) cold and arctic biomes. The most typical features of Mediterranean and semi-arid biomes – L-type IADFs showing xylogenetic plasticity – are shown in Pinus pinea, Arbutus unedo and Quercus ilex. Drought-induced disruptions of xylogenesis in arid and semi-arid biomes are illustrated by E-IADFs in Arbutus unedo and dark rings in Pinus halepensis. Finally, frost rings in Rhododendron myrtifolium and blue rings in Pinus sylvestris are presented as typical wood anatomy anomalies that occur due to disrupted cambial production and cell differentiation at the beginning or the end of vegetation period in the harsh conditions of cold arctic biomes.

Понимание взаимосвязей между температурой, осадками и радиальным приростом деревьев позволяет более точно прогнозировать последствия климатических изменений для лесных экосистем. Выявлены закономерности годового радиального роста сосны обыкновенной (Pinus sylvestris L.) на территории Байкальского государственного природного биосферного заповедника (Республика Бурятия). Построены индивидуальные и обобщенные хронологии ширины годичных колец, что позволило получить более полное представление о динамике роста этого вида. Большинство хронологий покрывают период с 1940 по 2019 годы. Результаты показывают, что радиальный прирост сосны обыкновенной имеет устойчивую обратную зависимость от температуры предыдущего лета: более высокие температуры прошлого лета приводят к пониженному радиальному росту в текущем году. Это может быть связано с ухудшением условий, вызванным засушливыми периодами или лесными пожарами, которые оказывают негативное влияние на здоровье деревьев. Кроме того, климатические данные подтверждают, что в регионе наблюдается рост средней температуры летних месяцев на 2°C и снижение июльских осадков в среднем на 60 мм. Эти изменения могут негативно сказываться на сезонном росте сосны обыкновенной, поскольку для ее нормального развития необходима достаточная почвенная влага в середине и конце лета.

Hemiboreal pine and pine-birch (Pinus sylvestris, Betula pubescens var. litwinowii) forests from the North-Western Caucasus were classified as two associations and four variants – Bistorto carneae–Pinetum sylvestris ass. nov. (var. Rhododendron luteum, var. Avenella flexuosa), Aconito nasuti–Pinetum sylvestris ass. nov. (var. Centaurea phrygia subsp. abbreviata, var. Geranim robertianum). They were included in the alliance Asyneumo campanuloides–Pinion sylvestris all. nov. and order Alchemillo sericatae–Pinetalia sylvestris Ermakov, Abdurakhmanova et Plugatar 2020 after cluster analysis performed. A new concept of the position of these Caucasian birch and pine-birch grass forests in the system of the European-Siberian class Brachypodio pinnati–Betuletea pendulae Ermakov et al. 1991 was proposed. All described associations belong to a special type of zonal small-leaved and light-coniferous hemiboreal forests of Northern Eurasia. It is confirmed by the distinct diagnostic species group of the class Brachypodio pinnati–Betuletea pendulae and their common ecological properties, floristic compositions and physiognomy. The North Caucasian hemiboreal forests together with analogous small-leaved and coniferous-small-leaved forests occurring in the upper part of the forest belt in the mountain ranges of Europe and Asia Minor may be considered as relic communities related by origin with the climate of the cold and dry periods of the Pleistocene.

In this study, some technological properties of test samples manufactured from heat-treated scotch pine (Pinus sylvestris L.) wood were analyzed. For this aim, experimental specimens were manufactured from heat-treated material at temperatures of 140 °C, 160 °C, 180 °C and 200 °C for 3 hours. Three different experimental groups were prepared from the sapwood of the log. The first group was massive wood (wood), the second group was laminated veneer lumber (LVL), and the third group was reinforced laminated veneer lumber (RLVL) using glass fiber fabric. One-component polyurethane based adhesive was used as a binder in this study. Air-dry density, equilibrium moisture content (EMC), and compressive strength parallel to the grain were determined to analyze the effects of the reinforcement on the LVL composite. Test results showed that reinforced heat-treated LVL samples with glass fibers increased both air dry density and compressive strength parallel to the grain. On the other hand, the EMC values of the test samples decreased with increasing heat treatment temperature and reinforcement process. Improving the some physical and mechanical properties of heat-treated wood material can contribute to the widespread use in buildings.

Climate models forecast warmer winter conditions, which could lead to an earlier spring xylem phenology in trees. Localized stem heat experiments mimic this situation and have shown that stem warming leads to an earlier cambial resumption in evergreen conifers. However, there are still few comprehensive studies comparing the responses to stem heating in coexisting conifers and hardwoods, particularly in drought-prone regions where temperatures are rising. We addressed this issue by comparing the responses (xylem phenology, wood anatomy, growth, and sapwood concentrations of non-structural carbohydrates—NSCs) of two pines (the Eurosiberian Pinus sylvestris L., and the Mediterranean Pinus pinaster Ait.) and a ring-porous oak (Quercus pyrenaica Willd.) to stem heating. We used the Vaganov-Shashkin growth model (VS model) to simulate growth phenology considering several emission scenarios and warming rates. Stem heating in winter advanced cambial phenology in P. pinaster and Q. pyrenaica and enhanced radial growth of the three species 1–2 years after the treatment, but reduced the transversal lumen area of earlywood conduits. P. sylvestris showed a rapid and high growth enhancement, whereas the oak responded with a 1-year delay. Heated P. pinaster and Q. pyrenaica trees showed lower sapwood starch concentrations than non-heated trees. These results partially agree with projections of the VS model, which forecasts earlier growth onset, particularly in P. pinaster, as climate warms. Climate-growth correlations show that growth may be enhanced by warm conditions in late winter but also reduced if this is followed by dry-warm growing seasons. Therefore, forecasted advancements of xylem onset in spring in response to warmer winters may not necessarily translate into enhanced growth if warming reduces the hydraulic conductivity and growing seasons become drier.

Palaeoecological investigations connected with extensive pre-bog, stone walls, and field systems at Kilmore, Dingle peninsula, Ireland, are presented. The main pollen profile, KLM I, spans the last 4000 years. When the record opened, pine (Pinus sylvestris) was already a minor tree, oak (probably Quercus petraea) was the main tall-canopy tree, and birch and alder were dominant locally. Substantial farming is recorded between ca. 1530 and 600 BCE (Bronze Age) when the stone walls were likely constructed. From ca. 560 CE onwards, intensive farming was conducted for much of the time. A largely treeless landscape emerged in the late twelfth century CE. Fine-spatial reconstructions of landscape and vegetation dynamics, including the timing of blanket bog initiation, are made. Post-glacial change in the western Dingle peninsula, based on published Holocene lake profiles and drawing on the new information presented here, is discussed. Reported are (a) fossil spores of the filmy ferns Hymenophyllum tunbrigense, H. wilsonii, and Trichomanes speciosum; (b) the first fossil pollen record for Arbutus unedo (strawberry tree) in the Dingle peninsula (540 CE); and (c) the first published records for Fagopyrum fossil pollen in Ireland, indicating that buckwheat was grown at Kilmore in the late eighteenth/early nineteenth centuries.

Key messageContinuing drought from winter to spring delayed the spring bud phenology of seedlings, and seedlings experiencing colder winter previously were less influenced by the severe drought.Water availability at the beginning of the growth phase, and even before it, is decisive in the phenology and annual cycle of forest trees, consequently affecting carbon sequestration and forest ecosystem balance. This is a novel experimental study on the effects of continuous drought throughout winter and early spring on tree performance. Two groups of Pinus sylvestris var. mongolica seedlings were overwintered in a Chinese solar greenhouse (BIG seedlings) and a plastic tunnel (SMALL seedlings). The seedlings were subjected to continuing droughts from winter to an extra 0 (control), 15 (D15), 30 (D30) and 45 days without irrigation (D45) after soil thawing next spring. Bud phenology, tree growth and physiology were examined. Bud phenological development, tree aboveground growth and root biomass growth were delayed in treatments D30 and D45 in both seedling types. SMALL seedlings had earlier bud phenology and were less influenced by drought than BIG seedlings. The drought-induced changes in spring phenology were associated with higher ABA and lower GA3 concentrations of needles. The phenology and growth differences between the seedling types might relate to soluble sugar concentrations of roots, needle chlorophyll content, needle chlorophyll fluorescence and acclimated morphological changes, such as root-shoot ratio. We suggest that in forest management, a big seedling size does not guarantee growth success, but attention should be paid to the proper conditions in overwintering and storing of the seedlings prior planting. Prolonged drought throughout winter and early spring should be avoided especially before planting the seedlings in an area prone to drought.

Dioryctria Zeller, 1846 (Lepidoptera: Pyralidae) is a significant genus whose species primarily infest coniferous trees and are predominantly distributed across the Northern Hemisphere. To date, 17 species within this genus have been recorded in China. This study reports the discovery of Dioryctria simplicella (Heinemann, 1863) in China. During field surveys in forests of Heilongjiang Province, D. simplicella was observed infesting the cones and trunks of Pinus sylvestris var. mongolica Litv. as larvae. Comprehensive morphological descriptions and diagnostic characteristics of the adult, larva, pupa, and egg stages of D. simplicella are provided herein to facilitate accurate species identification within the genus. Molecular phylogenetic analysis based on mitochondrial cytochrome c oxidase subunit I (COI) DNA barcoding sequences was conducted to assess the phylogenetic position of D. simplicella within Dioryctria. These results strongly support its species identity and clarify its phylogenetic relationships with congeners. This discovery not only expands the known diversity of Lepidoptera in China but also provides new data supporting taxonomic and phylogenetic studies of the genus Dioryctria.

The effect of environmental factors on water exchange parameters of Scots pine in old-growth forests of Karelia

Soil structure has an important role in storing and transporting substances, providing natural habitats for soil microorganisms, and allowing chemical reactions in the soil. A complex investigation on factors affecting soil structure characteristics under herbaceous (H), deciduous (D), mixed (M), and coniferous (SP—Scots Pine and NS—Norway Spruce) vegetation was conducted at three experimental stations—Gabra, Govedartsi, and Igralishte, located correspondingly in the Lozenska, Rila, and Maleshevska Mountains in South-West Bulgaria. The data set obtained includes soil structure indicators and physical, physicochemical, chemical, mineralogical, and microbiological parameters of the A and AC horizons of 11 soil profiles. Under different vegetation conditions, soil structure indicators respond differently depending on climatic conditions and basic soil properties. Regarding the plant available water capacity (PAWC), air capacity (AC), and water-stable aggregates (WSAs), the surface soil layers have an optimal structure in Gabra (H, D), Govedartsi (H, SP, NS), and Igralishte (H). The values for the relative field capacity (RFC < 0.6) showed that the studied soils were water-limited. The WSAs correlated with SOC in Gabra, while in Govedartsi and Igralishte, the WSAs correlated with the β-glucosidase known to hydrolyze organic carbon compounds in soil. The information obtained is important for soil quality monitoring under climatic and anthropogenic changes.

Extensive wildfires and logging have affected the Russian boreal forests in recent decades. Scots pine (Pinus sylvestris L.) forests are widespread in Russia and are one of the most disturbed tree species in Siberia. However, the effects of disturbance on soil CO2 efflux in the vast Siberian forests are still poorly understood. We used the LI 8100A infrared gas analyzer to study changes in soil CO2 efflux into the atmosphere in mature Scots pine forests in the Siberian central taiga five–six years following fires and logging. Measurements of soil CO2 efflux rates were performed on sites where automatic weather stations have been continuously operational since 2022, which gives us temporal patterns of meteorological fluctuations across forests with different disturbance histories. We found significant differences in soil efflux rates depending on the site and disturbance characteristics. In the undisturbed dry lichen-dominated forest, CO2 efflux was 4.8 ± 2.1 µmol m−2 s−1, while in the wet moss-dominated forest it was 2.3 ± 1.3 µmol m−2 s−1, with soil efflux in Sphagnum sp. being twofold of that in feather moss. Both fire and logging significantly reduced CO2 efflux, with a smaller reduction in soil CO2 efflux observed in the moss-dominated plots (5%–40%) compared to the lichen-dominated plots (36%–55%). The soil efflux rate increased exponentially with increasing topsoil temperatures in lichen-dominated Scots pine sites, with disturbed plots showing less dependence compared to undisturbed forest. In the wet moss-dominated Scots pine forest, we found no significant dependence of soil efflux on temperature for all disturbance types. We also found a positive moderate relationship between soil efflux and forest floor depth in both lichen- and moss-dominated Scots pine forests across all the plots studied. Our findings advance the understanding of the effects of fire and logging on the carbon cycle and highlight the importance of accounting for disturbance factors in Earth system models due to changing climate and anthropogenic patterns.

The increasing need for energy-efficient and acoustically optimized buildings has positioned cross-laminated timber (CLT) as a competitive material in sustainable construction. This study investigates the impact of perforation techniques on the thermal and acoustic performance of CLT panels produced from Scots Pine (Pinus sylvestris L.), Uludağ Fir (Abies bornmülleriana Mattf.), and Sessile Oak (Quercus petraea L.). Panels were manufactured in three- and five-layer configurations, incorporating perforation ratios of 10% and 20% in the internal layers. Experimental results demonstrated that increasing perforation ratios led to a decrease in thermal conductivity and transmittance, while significantly improving sound absorption coefficients. For instance, panels with 20% perforation exhibited a notable reduction in sound transmission, contributing to enhanced indoor acoustic comfort. These findings underline the potential of perforated CLT panels as multifunctional elements in both residential and commercial buildings. The study highlights the potential global impact of integrating such material innovations into sustainable construction practices, particularly in urban environments demanding high thermal efficiency and noise control.

Ericaceous understory shrubs and ericoid mycorrhizal fungal communities are ubiquitous in boreal forests, and their interactions with ectomycorrhizal and saprotrophic fungi may determine organic matter dynamics in forest soils. We followed decomposition of pine needle litter and mor-layer humus over 3 yr in a factorial shrub removal- and pine root exclusion experiment in an old-growth Scots pine (Pinus sylvestris) forest, to evaluate effects of fungal guilds on mass loss. Litter mass loss was 23% greater when ectomycorrhizal fungi were excluded suggesting increased saprotrophic activity, independently of ericoid shrub presence. However, this 'Gadgil effect' was only found after 17 months following a summer drought. By contrast, humus mass loss was overall stimulated by ectomycorrhizal fungi, while ericoid mycorrhizal shrubs appeared to counteract this effect, potentially caused by simultaneous addition of recalcitrant organic matter and inhibition of ectomycorrhizal decomposers. We conclude that competitive saprotrophic-ectomycorrhizal fungal interactions may slow early-stage litter decomposition, but this effect was small and inconsistent. Furthermore, interactions between ecto- and ericoid mycorrhizal guild members appear to determine the late-stage organic matter balance of boreal forest humus.

Surface properties of wood materials were determined before and after coating with cellulosic varnish doped with aloe vera gel. For this purpose, samples were prepared from Anatolian black pine (Pinus nigra subsp. pallasiana), fir (Abies nordmanniana subsp. bornmulleriana Mattf.), Ayous (Triplochiton scleroxylon K. Schum), and Scotch pine (Pinus sylvestris L.) woods in accordance with TS 53 (1981) and TS ISO 3129 (2021) principles and then coated with cellulosic varnishes doped with 0%, 5%, 10% and 15% aloe vera (L.) gel according to ASTM D3023-98 (2017) principles. Color changes according to ASTM D2244-21 (2021) and surface glosses according to TS EN ISO 2813 (2014) were determined on varnished surfaces. As the percentage of aloe vera gel in the varnish increased, the red color tone, yellow color tone, total color change, glossiness perpendicular and parallel to the fibers, and difference values decreased. Aloe vera gel can be preferred as an additive in cellulosic varnish in applications where the objective is no change or minimal change in the color and glossiness values, depending on type of wood and area of use.

In Germany, Pinus sylvestris is a dominant tree species, and many trees with large diameters are not utilised due to difficulties with processing. However, older pines have larger volumes of sapwood, and boards with a high sapwood content can be produced. The durability of boards from large-diameter (>50 cm) P. sylvestris trees, treated with furfurylation, acetylation, DMDHEU (1.3-dimethylol-4.5-dihydroxyethyleneurea), and SorCA (Sorbitol/Citric Acid), was assessed. The samples were taken from different sections along the longitudinal axis and the cross-section. The durability was tested against Coniophora puteana, Rhodonia placenta, and Trametes versicolor, according to the EN 113-2 standard. All treatments had a median mass loss < 5%, so classed as "highly durable" (Durability Class 1) against all fungi. DMDHEU had a large deviation in mass loss against Coniophora puteana and could potentially be classified as "moderately durable" (Durability Class 3), if based on the mean mass loss. The inner part of the end section had a higher mass loss, indicating that there was poorer retention of the treatment at this location. Overall, chemical modifications on large-diameter pine trees were effective at increasing durability. Utilising large-diameter pine trees can help to make use of regional resources and potentially reduce reliance on imported timber. With favourable mechanical properties and easy-to-treat sapwood, large-diameter P. sylvestris trees could be used for commercial treatments.

In this study, the biological resistance of Scotch pine (Pinus sylvestris) and beech (Fagus orientalis) wood samples which impregnated with individual and combinations of multi-functional compounds. Artificial antioxidant (A), GRAS compounds (G) and nano-SiO2 (N) were chosen as multi-functional compounds. Firstly, the wood samples were impregnated single, binary and ternary combinations of impregnation solutions. Larvicidial resistance of pine samples was investigated against to Hylotrupes bajulus. Termitidicial resistance of all samples were determined using Subterranean termites Reticulitermes. Also, Gloeophyllum trabeum and Poria placenta were used for fungal resistance of beech and pine samples, respectively. Synergistic effects were calculated based on the fungal results. It was concluded that binary combinations of A+G and G+N and also the ternary combination (A+G+N) have a synergistic effect in binary variations for pine wood samples while A+G and A+N binary combinations show synergistic effect for beech wood samples. In addition, it is seen that the ternary combination also has a synergistic effect as in beech wood samples.

This article discusses the possibility of using an assessment of biological damage as a result of a complex of abiotic factors, including anthropogenic factors. A decrease in the productivity of woody plants, including Scots pine, under the influence of abiotic factors can be considered as a failure of the ecosystem and its trophic levels to receive part of the flows of matter, energy and information and, therefore, considered damage to the environment, or biological damage

Abstract Logistic regression has been used to model individual tree mortality. However, unequal measurement intervals limit the use of reasonable link functions. Although marginal and mixed-effects models have been used, a comparison of these models for predicting mortality in new stands is lacking. We developed models for predicting the mortality of Scots pine (Pinus sylvestris) trees in Finland. The modelling data comprised 44 thinning experiments (127,057 tree-level observations), and 50% of the experiments were randomly selected for model evaluation (43 experiments, 112,518 tree-level observations). A complementary log–log model was used to predict mortality probability based on tree and stand characteristics and thinning effects. The measurement period length was added as an offset variable. The marginal (population-average) and mixed models with random effects (site, plot, and year) were fitted and evaluated. The evaluation consisted of fit statistics, comparisons of predicted and observed mortality rates, and simulations using the Motti stand simulator. The mixed models clearly provided better statistical fits than the marginal model. The evaluation with the Motti simulator showed the most accurate prediction in terms of stem number (N) and stand basal area (G) when using the marginal model. All models, except the random year effect, resulted in maximum G values that remained at a reasonable level in the prolonged Motti simulations. The current survival model in the Motti simulator is based on a relative density index derived from the self-thinning line and provides good prediction accuracy. Based on the new BAL-based models, we recommend the marginal model as an option to the current model.