Scots Pine Trees Research Articles

Adventitious roots as a source of information in reconstructing the activity of modern aeolian processes in the temperate climate zone: A case study from the Kozłów sandy area (SW Poland)

This paper presents a spatial-temporal reconstruction of inland dune movements at an anthropogenic active sandy area known as the Kozłów Desert, SW Poland. This unique sandy area, with assemblages of aeolian forms typical of “true” deserts, is an inactive military training ground (decommissioned in 1992) where military activity led to the initiation of geomorphic processes. The reconstruction was carried out based on the growth reaction characteristics of Scots pine (Pinus sylvestris L.) and downy birch (Betula pubescens L.) trees. 14 increment cores were collected from 12 trees and analysed with standard dendrochronological techniques. Samples of adventitious roots from all the trees examined were collected and prepared to extend the analyses and check their usefulness in dating modern geomorphic processes. The adventitious roots of pine and birch were found to react differently to burial, in terms of both reaction time and the shape of the root system. Growth-ring widths and wood anatomy were indicative of sudden or multi-stage sand movement, thus confirming the usefulness of adventitious roots as an additional source of information about aeolian process activity. More broadly, the study shows that the dynamics of landforming processes can be assessed more accurately and reliably by using such a combination of methods, comparing data from roots to data from tree trunks.

Advantages and limitations of an interdisciplinary approach in woodland archaeology: An example of 18th-19th century tar production in European temperate forest

Tar production was an important part of forest management until the beginning of the 20th century. Tar – used for many purposes – from glue, through boatbuilding, to a pharmacy – was widely produced throughout Europe. As early as in the 18th century, in some parts of Europe, tar production became massive. In the eastern part of Europe, however, that process was still carried out with simple methods known from the Middle Ages. With Airborne Laser Scanning, we have detected 53 traces of tar processing in the Polish part of the Białowieża Forest. In 2019, one of the features was archaeologically excavated to identify its preserved structure/architecture and collect samples for laboratory tests. The outcomes of the archaeological test trench did not provide answers to many research questions. Therefore, it was decided to apply an interdisciplinary approach to determine the utilised raw material, timing and the process of tar production. In result of the dendrochronological and anthracological analyses, it was found that diverse parts of Scots pine trees were used for tar production. Our tree ring analyses provided also the first information about the absolute chronology of the tar kiln activity. To obtain information on the tar production process, i.e. the burning temperature and the characteristics of the obtained tar, we performed chemical analyses of the tar samples (microscopic and Fourier Transform Infrared, FTIR). This multidisciplinary case study of one of the many sites from the Białowieża Forest provided basic information about the methods of tar production in modern times and their probable impact on the immediate vicinity of the forest. However, such an interdisciplinary approach is limited by both the quantity and quality of the preserved artefacts, found during archaeological excavations.

Sphaeropsis sapinea (Fr.) Dyko & B. Sutton in Pinus sylvestris L. stands affected by long-term drought

Abstract In this study, the fruit bodies (pycnidial) colonization and spore presence of Sphaeropsis sapinea (Fr.) Dyko & B. Sutton on Scots pine (Pinus sylvestris L.) trees in stands affected by long-term drought in the Czech Republic were evaluated. A total of 520 cones at four sites were evaluated every 1.5 months from June 2019 to December 2020. The pycnidia of S. sapinea in relation to colonization by subcortical insects in inner bark and wood, and wood-decaying fungi a total of 340 trunks at 17 sites during the autumn of 2020 were also evaluated. Pycnidial colonization of S. sapinea on cones was significantly higher at the site with the highest air humidity and significantly lower in the sampling periods of June 2019, August 2019, and November 2019, which were characterized by low precipitation levels. S. sapinea spore presence on cones was significantly higher at sites in Bohemia compared to those in Moravia, in sites with higher air humidity, and in three consecutive sampling periods in March 2020–June 2020. Pycnidial colonization of S. sapinea on trunks was significantly positively dependent on the colonization of subcortical insects in both inner bark and wood, but not with the colonization of wood-decaying fungi. The results of this study show a positive relationship between high humidity and colonization by subcortical insects in inner bark and wood with S. sapinea on Scots pine.

A radioecological model with moisture-dependent Kd: Application to 129I and 79Se natural release to a grassland

A radioecological model previously developed to simulate chlorine cycling in a Scots pine forest was modified to examine the effect of soil hydrochemical conditions on the fate of 129I and 79Se released to a grassland through natural discharge of contaminated groundwater. To this end, the constant solid-liquid distribution coefficient (Kd) in the original model was replaced by a parametric equation to estimate 129I and 79Se Kd values from soil saturation — as a proxy for soil redox potential — and a set of Kd values determined experimentally under oxic and anoxic conditions. Additionally, the multi-compartment Scots pine tree module was replaced by a two-compartment module to represent 129I and 79Se cycling in grass. Simulations undertaken with the model indicated a considerable effect of soil redox conditions on 129I and 79Se accumulation in the soil column, especially in the saturated subsoil above the water table. The constant Kd overestimated 129I accumulation in the soil in relation to the parametric Kd. In contrast, the constant Kd underestimated 79Se accumulation in the soil. These results have implications for radiological impact assessments, specifically regarding the degree of conservatism in the Kd used in the assessment. In respect of bioavailability to grass, the simulated soil-to-plant transfer factors of 129I and 79Se compared favourably with values reported in the literature for similar soils and plant species, giving confidence in the model performance. The model presented here is a step forward in radioecological modelling as it includes the key processes that drive radionuclide transfers in soil-plant systems and the effect of soil redox conditions on sorption. The model can be readily extended to other cultivated lands and release scenarios to predict radionuclide transfer up the food chain.

CREATION OF DECORATIVE FORMS OF SCOTS PINE FOR THE GREENING OF URBANIZED ENVIRONMENT

The features of creating decorative forms from Scots pine trees are considered. It has been established that, as a result of mechanical damage (death of an apical bud or an apical shoot) and subsequent regeneration processes in pine trunks, two main directions of post-traumatic deformations of young pine trunks stand out - violation of monopodial branching and occurrence of multi-stemming. In the case of the death of an apical bud or apical shoot, in early spring, the growth of shoots from whorl buds is activated and their vertical reorientation occurs. After a short period of relative multi-stemming, one of the shoots from whorl buds takes the place of the central shoot. Formation of multi-stemming occurs in the case of the death of an apical shoot, mainly in late spring-summer period. There is also an increased growth of shoots from whorl buds and their vertical reorientation. All shoots formed from whorl buds retain their vertical orientation in the future with subsequent formation of several separate stems. It is shown that the processes of mechanical damage-regeneration are also reflected in the condition of trunk wood in the places of damage. In trunk areas where mechanical damage and subsequent regeneration took place, a noticeable increase in the basic density of wood is observed - by 15-20 % in case of shoot replacement and by 25-45 % in case of multi-stemming. The content of late wood also increases - by 10-30 % in case of shoot replacement and by 15-35 % in case of multi-stemming. It is recommended, to create decorative forms, to select pine trees no older than 8-10 years old, with an average growth rate in height. Decorative forms of Scots pine require annual adjustments.

Usporedna analiza utjecaja klimatskih čimbenika na radijalni rast autohtonih vrsta borova (Pinus spp.) u središnjoj Bosni i Hercegovini

In central Bosnia and Herzegovina, in the Zavidovići-Teslić area, the study of the radial growth of Austrian and Scots pine (autochthonous pine species) trees was conducted using the dendrochronological method in order to identify the differences between the species in terms of the influence of climatic variables on the tree ring formation. Trees were sampled in five experimental areas or five sites. The first site had a Scots pine stand, while the second had an Austrian pine stand, and the other three sites had mixed stands of Scots and Austrian pine. Cross-dating was conducted using visual on-screen techniques of CDendro software and statistical methods using Cofecha software. The tree ring series were standardized using the Arstan program and cubic smoothing spline. It produced Scots pine regional chronology, 145 years long (1870-2014), and Austrian pine regional chronology, 180 years long (1835-2014). Correlation analysis of the relationship between the index of tree-ring width and precipitation and temperature in the characteristic periods of the year showed a negative effect of temperature (except in winter months) and a positive effect of precipitation on the tree ring formation. The statistically significant dependence of the tree-ring width index on the SPEI indices indicates a significant impact of moisture deficiency on the tree ring formation in the period from June to August (r = 0.33 in June, r = 0.45 in July and r = 0.47 in August) for Scots pine and in the period from June to September (r = 0.36 in June, r = 0.43 in July, r = 0.47 in August and r = 0.30 in September) for Austrian pine. The analysis of the relationship between climatic parameters and the chronologies of Scots and Austrian pine shows similar relationships between radial growth and climate but the influence of climate is somewhat more pronounced in Austrian pine. In the study area, the radial growth of both tree species is significantly determined by climate conditions. In other words, the chronology of these species has a good climatic signal, especially the drought signal in the summer months.

Tracking Individual Scots Pine (Pinus sylvestris L.) Height Growth Using Multi-Temporal ALS Data from North-Eastern Poland

In this study, we analyzed the change in tree height of 2594 Scots pine (Pinus sylvestris L.) trees with respect to the distribution among different forest sites: HCfs—hydrogenic coniferous forest site; MCfs—mineral coniferous forest site; MMfs—mineral mixed forest site. We obtained tree height information from three independent airborne laser scanning (ALS) point clouds acquired in north-eastern Poland over a 5-year interval in 2007, 2012, and 2017 using verified tree crown segments. We performed a comparative analysis of digital terrain models (DTMs) calculated from analyzed point clouds, indicating that the highest elevation differences were observed in the case of data from 2007. The analyses showed that tree growth varies significantly depending on the forest site productivity and the stage of tree development, which was described as initial tree height instead of age—commonly used in such studies. In conclusion, it is possible to indicate the significant information potential of using multitemporal ALS data to track individual tree height changes. These field data, combined with meteorological data, can be successfully used to predict changes in the abundance of stands depending on the forest site productivity. We have built Scots pine growth models for each forest site, which indicates that it is possible to predict the change in the tree stand height.

Assessment of the Mass and Surface Area of the Scots Pine (Pinus sylvestris L.) Needles

The assessment of the surface area of all leaves from a tree crown is regarded as one of the key parameters in scaling ecophysiological processes, such as growth, carbon budget, and water management. The purpose of this study was to investigate the variation of the mass and surface area of Scots pine needles, obtained from trees growing in the same habitat conditions but at different stock densities, therefore occupying different biosocial positions. The mass of needles and the leaf area index (LAI) were determined for an even-aged 33-year-old Scots pine stand located at a fresh mixed coniferous forest site in southwest Poland (50°32′ N; 17°42′ E). The needles, collected from all the sample trees, were subjected to a biometric analysis to determine the total mass of needles from each tree, the mass of 1000 needle pairs, the number of needles per crown, and the needle length distribution. Based on the actual measurements, we derived allometric equations for finding the fresh mass (FMN) and the surface area of the needles (SN), using the diameter at breast height (DBH) as an independent variable. The relationships between the mass of the needles and the DBH were significant (p < 0.0001), and so were those between the surface area of the needles and the DBH (p < 0.001). The fresh mass of needles for the tree stands varied from 6458 kg·ha−1 to 11,102 kg·ha−1. The LAI was in the range of 3.2 to 5.4 m2·m−2. The mean value of the LAI for the Scots pine stand was 4 m2·m−2. Further studies are required and more algorithms need to be developed for the quantitative assessment of the LAI in Scots pine trees, using a larger number of sample trees with more varied biometric features.

Assessing Structural Complexity of Individual Scots Pine Trees by Comparing Terrestrial Laser Scanning and Photogrammetric Point Clouds

Structural complexity of trees is related to various ecological processes and ecosystem services. To support management for complexity, there is a need to assess the level of structural complexity objectively. The fractal-based box dimension (Db) provides a holistic measure of the structural complexity of individual trees. This study aimed to compare the structural complexity of Scots pine (Pinus sylvestris L.) trees assessed with Db that was generated with point cloud data from terrestrial laser scanning (TLS) and aerial imagery acquired with an unmanned aerial vehicle (UAV). UAV imagery was converted into point clouds with structure from motion (SfM) and dense matching techniques. TLS and UAV measured Db-values were found to differ from each other significantly (TLS: 1.51 ± 0.11, UAV: 1.59 ± 0.15). UAV measured Db-values were 5% higher, and the range was wider (TLS: 0.81–1.81, UAV: 0.23–1.88). The divergence between TLS and UAV measurements was found to be explained by the differences in the number and distribution of the points and the differences in the estimated tree heights and number of boxes in the Db-method. The average point density was 15 times higher with TLS than with UAV (TLS: 494,000, UAV 32,000 points/tree), and TLS received more points below the midpoint of tree heights (65% below, 35% above), while UAV did the opposite (22% below, 78% above). Compared to the field measurements, UAV underestimated tree heights more than TLS (TLS: 34 cm, UAV: 54 cm), resulting in more boxes of Db-method being needed (4–64%, depending on the box size). Forest structure (two thinning intensities, three thinning types, and a control group) significantly affected the variation of both TLS and UAV measured Db-values. Still, the divergence between the two approaches remained in all treatments. However, TLS and UAV measured Db-values were consistent, and the correlation between them was 75%.

Intimate mixtures of Scots pine and Sitka spruce do not increase resilience to spring drought

Understanding how we can increase the resilience of forest systems to future extreme drought events is increasingly important as these events become more frequent and intense. Diversifying production forests using intimate mixtures of trees with complementary functional traits is considered as one promising silvicultural approach that may increase drought resilience. However, the direction and magnitude of the drought response of mixed-species stands relative to monospecific stands of the same species can vary with species identity, relative abundance and levels of competition in a focal tree's immediate neighbourhood. Using a long-term experiment where tree-level mortality and the neighbourhood composition of each tree was known, we assessed the radial growth response of 24-year-old Scots pine (Pinus sylvestris) and Sitka spruce (Picea sitchensis) trees in intimately mixed and monospecific stands to a short-duration, high-intensity spring drought in Scotland. Mixing proportions included 25:75, 50:50 and 75:25 of P. sylvestris and P. sitchensis. At the species level, Scots pine was more drought resistant and resilient than Sitka spruce, while Sitka spruce showed higher recovery. Surprisingly, neither pre-drought tree size nor neighbourhood competition were significantly associated with resistance or resilience to drought, and trees of both species within monospecific stands showed higher recovery and resilience than trees growing in mixed stands. Our study suggests intimate mixtures of these two species may not be an effective way to mitigate the negative impacts of future extreme spring drought events. Given that these two species comprise almost 70% of coniferous forests in the UK, our results highlight the pressing need to better understand their vulnerability to drought and the conditions under which intimate mixtures of these species could be beneficial or detrimental. Such knowledge is essential if we are to enable forest managers to effectively plan how to adapt these forests to the challenges of a changing climate.

The Possibility of Studying the Processes of Interconversion of Volatile Compounds of Needles on the Basis of Static Data

The results of a study of the population structure of biochemical features (a large number of volatile needle terpenoids) on large samples of Scots pine trees are presented. Data were analyzed using correlation, cluster, and principal component analysis. Significant conjugation of the content of all isolated needle compounds was shown. Features of the correlation structure of terpenoids indicate that the processes of their group synthesis can be simultaneously triggered in plants. It is concluded that it is possible to use static data obtained on large samples of trees for a preliminary study of the processes of interconversions of terpenoid compounds in coniferous plants, which are characterized by high reactivity and the complexity of their study by chemical methods.

Conifer tree species and age as drivers of epiphytic lichen communities in northern European production forests

AbstractThe epiphytic lichen species richness and community composition was compared for 600 living trees distributed within the interior of 60 Scots pine and Norway spruce monoculture stands in southern Sweden. A higher species richness, and more unique species, was found on trees of Scots pine than of Norway spruce, and distinctive communities were associated with the two tree species. Lichen species composition also shifted between the 30-, 55- and 80-year-old stands, although there was no significant difference in species richness between the different age classes. Tree species and age of the stand explained most of the variation in community composition (41%), with additional variance explained by lichen proximity to the ground (6%) and aspect (1%) (northern/southern side of trunk). Scots pine and Norway spruce share many attributes, such as both being conifers with acidic bark properties and having a similar geographical distribution in Fennoscandia. However, our study showed that species richness and community composition can nevertheless diverge in stands dominated by these two tree species. Since the occurrence of red-listed species was low in these stands, we suggest that 80-year rotations are not long enough for the occurrence of the many rare and specialized lichen species that require old forest structures and long forest continuity in this region.

Assessment of Effective Wind Loads on Individual Plantation-Grown Forest Trees

Quantifying wind loads acting on forest trees remains a major challenge of wind-tree-interaction research. Under wind loading, trees respond with a complex motion pattern to the external forces that displace them from their rest position. To minimize the transfer of kinetic wind energy, crowns streamline to reduce the area oriented toward the flow. At the same time, the kinetic energy transferred to the trees is dissipated by vibrations of all aerial parts to a different degree. This study proposes a method to estimate the effective wind load acting on plantation-grown Scots pine trees. It evaluates the hypothesis that the effective wind load acting on the sample trees can be estimated using static, non-destructive pulling tests, using measurements of stem tilt under natural wind conditions and static, non-destructive pulling tests. While the analysis of wind-induced stem displacement reconstructs the temporal tree response dynamics to the effective wind load, results from the pulling tests enable the effective wind load quantification. Since wind-induced stem displacement correlates strongly with the sample trees’ diameter at breast height, the effective wind load estimation can be applied to all other trees in the studied stand for which diameter data is available. We think the method is suitable for estimating the effective wind load acting on trees whose wind-induced response is dominated by sway in the fundamental mode.

Tracheidogram’s Classification as a New Potential Proxy in High-Resolution Dendroclimatic Reconstructions

Quantitative wood anatomy (QWA) is widely used to resolve a fundamental problem of tree responses to past, ongoing and forecasted climate changes. Potentially, QWA data can be considered as a new proxy source for long-term climate reconstruction with higher temporal resolution than traditional dendroclimatic data. In this paper, we considered a tracheidogram as a set of two interconnected variables describing the dynamics of seasonal variability in the radial cell size and cell wall thickness in conifer trees. We used 1386 cell profiles (tracheidograms) obtained for seven Scots pine (Pinus sylvestris) trees growing in the cold semiarid conditions of Southern Siberia over the years 1813–2018. We developed a “deviation tracheidogram” approach for adequately describing the traits of tree-ring formation in different climate conditions over a long-term time span. Based on the NbClust approach and K-means method, the deviation tracheidograms were reliably split into four clusters (classes) with clear bio-ecological interpretations (from the most favorable growth conditions to worse ones) over the years 1813–2018. It has been shown that the obtained classes of tracheidograms can be directly associated with different levels of water deficit, for both the current and previous growing seasons. The tracheidogram cluster reconstruction shows that the entire 19th century was characterized by considerable water deficit, which has not been revealed by the climate-sensitive tree-ring chronology of the study site. Therefore, the proposed research offers new perspectives for better understanding how tree radial growth responds to changing seasonal climate and a new independent proxy for developing long-term detailed climatic reconstructions through the detailed analysis of long-term archives of QWA data for different conifer species and various forest ecosystems in future research.

Developing single and double tree volume equations for Scots pine (Pinus sylvestris L.) trees: A case study in Bozalan and Çubuk forests

Bu çalışmada Ankara Orman Bölge Müdürlüğü, Kızılcahamam Orman İşletme Müdürlüğü’ne bağlı Bozalan Orman İşletme Şefliği ile Ankara Orman İşletme Müdürlüğü’ne bağlı Çubuk Orman İşletme Şefliği sınırları içerisinde yer alan sarıçam meşcerelerindeki ağaçların hacim denklemleri modellemek üzere tek girişli ve çift girişli ağaç hacim denklemleri geliştirilmiştir. Tek girişli hacim denklemleri için 6 ve çift girişli ağaç hacim denklemleri için ise 27 farklı fonksiyon, tahminin standart hatası, ortalama hata, ortalama mutlak hata, toplam hata yüzdesi ve ortalama mutlak hata yüzdesi değerleri ve belirtme katsayısı olmak üzere farklı 6 adet başarı ölçütüne göre karşılaştırılmıştır. En başarılı olarak belirlenen tek girişli ağaç hacim denklemi %86,04, çift girişli ağaç hacim denklemi ise %96,63‘lük model açıklayıcılığına sahiptir. En başarılı denklem olarak belirlenen tek ve çift girişli ağaç hacim denklemlerinin çalışmaya konu bölgedeki sarıçam ağaçları için uygunluğu bağımsız bir veri grubu ile test edilerek p<0,05 önem düzeyi ile uygun olduğu belirlenmiştir.

Changes in Soil Properties and Scots Pine Tree Growth Induced by Different Soil Ploughing Prior to Afforestation: A Case Study

Numerous studies have confirmed that forests have the potential for a significant contribution to carbon sequestration, but afforestation of former agricultural land can be attempted to adopt technologies that further encourage carbon sequestration. The aim of this study was to evaluate the impact of different soil cultivation methods, including deep ploughing and soil cultivation by making microsites and furrows prior to afforestation of former agricultural land, on chemical soil properties and tree growth in 20 years old Scots pine plantations. A naturally regenerated Scots pine stand, representing the non-ploughed soil, was included as a control site. Deep ploughing, among other soil cultivation methods, significantly altered the chemical soil properties. Furthermore, significant effects were indicated in the sites afforested after cultivation by making furrows. A recent study found that, due to deep soil cultivation, higher stocks of soil organic carbon (SOC) and total nitrogen (N) were incorporated into deeper soil layers and were protected from direct environmental impact. Twenty years post afforestation in deeply ploughed sites, we still found a decreased C:N ratio and disbalanced relationship between the concentrations of SOC and total N. The SOC and total N stocks were higher in the subsoil than in the topsoil in the sites afforested after deep ploughing. Moreover, deep ploughing and soil cultivation by furrows prior to afforestation resulted in higher total SOC and total N stocks in the forest floor and mineral 0–80 cm soil layer. A higher total phosphorus (P) concentration in the subsoil and total potassium (K) in the upper mineral soil layer were obtained in the deep ploughing sites and the sites, cultivated by furrows, compared to the non-ploughed sites. Significantly higher total P stock per entire profile was found for the deep ploughing sites and the sites cultivated by furrows than in the naturally regenerated stand. Different soil cultivation methods caused no differences in tree diameter at breast height (DBH) in 20 years old Scots pine stands both in the afforested sites and in the naturally regenerated forest. However, significantly larger tree height in all afforested sites than in the naturally regenerated Scots pine stands was obtained. A lower differentiation in tree DBH was obtained in the deep ploughing sites.

Cambioxylophagous Pests of Scots Pine: Ecological Physiology of European Populations—A Review

Climatic extremes have been gathering momentum since the 1880s and are believed to be a long-term factor increasing the mortality of Scots pine trees, Pinus sylvestris (L.) in Europe. Weather monitoring over the past 120 years shows that, in Central Europe, surface air temperatures grow at a rate of 0.18°C per decade. Many changes due to these abiotic stressors are already visible in the forests’ canopy and biodiversity. But the influence of the rise in temperature and in precipitation deficiency brings one more player into this die-back scheme. Bark beetles, and their increasing outbreaks, are further agents acting to accelerate and expand the impacts of weather on trees. While P. sylvestris react to abiotic stressors by decreasing functions of the hydraulic system, mainly the defense system, for bark beetles, warming is a profitable condition. Various bionomy processes are modified: vegetation seasons prolong, larval growth and development rates accelerate, reproductive potential rises, and overwintering success increases. Thus, the insect populations grow, and the infestation pressure on weakened hosts intensifies. Finally, even species of small ecologic importance can cause extensive losses of forest cover. Furthermore, international trade and intercontinental transportation support the potential threat of spreading forest pests far away from their original geographic range. Together with climatic amelioration, pests may adapt to new conditions, establish new prosperous populations, disperse rapidly, and cause prodigious losses. However, detailed information about cambioxylophagous pests on P. sylvestris in Central Europe is still missing. The purpose of our review is to map the bionomy and behavior of six bark beetle species—in particular, the sharp-dentated bark beetle, Ips acuminatus (Gyllenhal, 1827), the six-toothed bark beetle, Ips sexdentatus (Börner, 1767), the common pine shoot beetle, Tomicus piniperda (Linnaeus, 1758), the lesser pine shoot beetle, Tomicus minor (Hartig, 1834), the pine shoot beetle, Tomicus destruens (Wollaston, 1865), the Mediterranean pine engraver, Orthotomicus erosus (Wollaston, 1857) (Coleoptera: Curculionidae: Scolytinae), and the steel-blue jewel beetle, Phaenops cyanea (Fabricius, 1775) (Coleoptera: Buprestidae)—on P. sylvestris in Central Europe, to compare and summarize the available data on European populations, and to try to propose ideas and directions for future research.

Radiocarbon generation and atmospheric release assessment from nuclear power plant with RBMK type reactors

The article provides the results of the estimation of 14C nuclide generation and release from the systems and structures of RBMK-1500 reactors operated at Ignalina NPP. The main circulation circuit and gaseous circuit of this type of reactor are the primary sources of 14C generation and airborne release, evaluated to be 0.491 and 0.367 TBq per one calendar year (10.5 months of effective reactor operation at 1350 MWe power), respectively. The analysis of the operation specifics of these systems showed that they don’t provide an effective barrier to contain 14C due to the 14CO2 chemical form of radiocarbon in RBMK reactors, i.e., 100% release (0.858 TBq/year) have been evaluated available for atmospheric release. These results have been compared with the atmospheric releases evaluated from the 14C activity concentration measured in Scots pine tree (Pinus Sylvestris L.) ring samples by single stage accelerator mass spectrometer (SSAMS, NEC, USA) at Vilnius Radiocarbon facility, resulting to airborne release value of 1 TBq/year for one RBMK-1500 reactor. Slightly higher value reproduced from the tree ring samples indicates that the reactor graphite stack might be also a source of 14C releases of about 0.14–0.24 TBq/year. Based on similar design features the results of the study can be easily projected to the RBMK-1000 reactors rescaling 14C source term according to the lower reactor power.

The needle percentage in the leafy shoot biomass of Scots pine in climate gradients of Eurasia

The efficiency of using photosynthetically active radiation by trees largely depends on the architecture of the assimilation apparatus in their crown. It is known that an increase in the level of atmospheric pollution is accompanied, on the one hand, by an increase in the foliage density on the leafy shoot length, and on the other hand, by an increase in the transparency of the crown due to the expansion of the leafless inner part of the crown. On this basis, we assume that the foliage percentage of leafy shoots (PL) is a sensitive indicator of changes in growing conditions not only due to environmental pollution, but also in broader ecological aspects, in particular, in the geographical or climatic gradients of Eurasia. For this purpose, a database of empirical data has been formed in the amount of 558 model trees of Scots pine of natural and artificial origin from 6 regions of Northern Eurasia with a measured percentage of needle in the leafy shoot biomass. A regression model has been designed, in which the contributions of mensuration variables (tree age and stem diameter), climatic variables (temperature and precipitation) and the origin of stands (natural and artificial) to explain the variability of the desired PL indicator are 15, 53 and 30 %, respectively. It is concluded that with a decrease in annual precipitation from 600 to 300 mm, there is an increase in PL by 0.2..0.3% for every 10 mm of annual precipitation, both in natural stands and in plantations. When the January temperature decreases from 0°C to -20 °C, PL increases by 0.8...1.0% for each 1°C. Thus, the foliage percentage of leafy shoots of Scots pine is an indicator of changes in growing conditions in the climate gradients of Eurasia.

Modeling Optimal Forest Rotation Age for Carbon Sequestration in the Great Khingan Mountains of Northeast China

The growing concern about climate change has led to the rise of carbon cycle research. Forest cutting planning affects the carbon cycle due to the carbon sequestration function of forests. In this work, we propose a planning model for determining the regeneration cutting age of forests to optimize carbon sequestration and improving the associated economic and ecological benefits. We first built a model based on the carbon sequestration consumption of forest products and forest carbon sequestration to predict the change in forest carbon sequestration over time. The accuracy of the model was verified with forest data from the Great Khingan mountains. Furthermore, we added in economic and ecological factors to build an improved model, which was also applied to the Great Khingan forest. The improved regeneration cutting ages were calculated as 65, 134, 123, 111 and 73 years for white birch, larch, Scots pine, oak, and poplar trees for natural forests, whereas the ages were 34, 65, 64, 77 and 37 years for planted forests, respectively. It can be predicted that the total carbon sequestration in the Great Khingan forests will accumulate to 974.80 million tons after 100 years. The results of this study can provide useful guidance for local governments to develop a sustainable timeline for forest harvesting to optimize carbon sequestration and improve the associated economic and ecological benefits.