Forest Site Types Research Articles

The influence of forest site types on the distribution of moose Alces alces in north-eastern Poland

ABSTRACT Movements of moose are caused by variations in resource availability such as food, shelter and the energetic cost of foraging. These variables are important in forest and population management. Therefore, the main objective of the present study was to estimate the influence of forest site types on the distribution of the non hunted moose population in February and March 2020 in the Augustów Forest, a 1102.0 km2 forest complex in north-eastern Poland. In the study area, 20 sampling plots were distributed over a total area of 91.4 km2, where six teams, each consisting of 30 people, observed moose to estimate population numbers. The average population density was 1.22 ± 0.19 moose per km2 and ranged from 0.21 to 3.40 animals/km2. The total population number estimated this way amounted to 1344 animals. Non-linear regression demonstrated a positive relationship between the percentage of hygric-wet forest site types in the sampling plot area and the moose population distribution (r = 0.735, n = 20, p = 0.0096). In winter, these habitats are a critical refuge for moose. For this reason, tree harvesting and hunting in hygric-wet forest site types should be limited during this period.

Features of the modern distribution of 137Cs in soils under overmoistened growth conditions of black alder forests in Zhytomyr Polissia, Ukraine

Research on the modern distribution of 137Cs in soils of different forest site types in black alder (Alnus glutinosa (L.) Gaerth.) stands was conducted. In forest litter, there is not a high percentage of its total activity in soil: in moist fairly fertile site type (C3) – 13.4 %, damp fairly fertile site type (C4) – 16.3 %, and wet fairly fertile site type (C5) – 3.8 %. The mineral part of the soil in moist and damp fairly fertile site type is characterized by decreased density of radioactive contamination of soil layers with depth. In wet fairly fertile site type, this indicator increases to a depth of 6 - 8 cm and decreases with further deepening. A 10-cm layer of moist fairly fertile site type (C3) contains 61.8 % of the total radionuclide activity in soil, damp fairly fertile site type (C4) – 68.1%, and wet fairly fertile site type (C5) – 70.1 %, correspondingly; a 20-cm layer has 75.4, 78.3, 91.9 % and a 30-cm layer – 80.9, 82.2, 96.0 % of the total radionuclide activity.

Особенности генетической структуры популяции Pinus sylvestris L. в степной зоне Европейской России

The article presents the results of studу of the genetic structure of Scots pine (Pinus sylvestris L.) growing in the ecologically favorable territory of the steppe zone of European Russia. 35–year-old pine forest plantations (the Voronezh Region, Kantemirovskiy District, the 3rd bonitet class, forest site type – A1, a random sample, 60 trees) have been chosen as the object of the study. Genetic diversity has been examined on the basis of the microsatellite analysis of 18 SSR-loci (14 EST-SSR-loci and 4 nSSR-loci) and two isozymic loci (shikimate dehydrogenase and glutamate dehydrogenase – or Skdh and Gdh, respectively). It has been revealed that in the studied population, all the used microsatellite loci, with the exception of lw_isotig02842, are polymorphic. The average values of genetic variability calculated from the microsatellite loci have been obtained: the proportion of the polymorphic loci – 94.44 %, the average number of alleles per locus – 3.500, the average effective number of alleles – 2.466, the observed and expected heterozygosity – 0.209 and 0.493 respectively; the Wright fixation index – 0.577. In terms of the level of allelic diversity, the plantation is characterized by relatively lower values of genetic and statistical population parameters (the average observed and expected heterozygosity) compared to the natural forest-steppe populations of the Central Chernozem Region. A high positive Wright fixation index indicates the presence of an increased proportion of inbreeding in the steppe population trees. The reasons and possible nature of the revealed phenomenon are discussed. Based on the isoenzyme analysis, the genetic structure of the Skdh and Gdh loci is examined. The results of the analysis indicate a high frequency of the rapid allele Skdh-11 (82 %) and the embryonic semi-lethal allele Gdh-11 (22 %), which, apparently, can be considered as one of the mechanisms of the population adaptation to the conditions of a warmer and drier climate of the steppe region. A deficiency of glutamate dehydrogenase heterozygotes has been established. It has also been noted that the groups of EST-SSR-loci and nSSR-loci differ in the level of genetic variability and population structure. It has been shown that the combined use of different types of genetic markers makes it possible to obtain more complete and objective information on the distinctive features of the genetic structure of pine forests in the optimal and pessimal zones of the range. The studied 18 microsatellite loci can be used to assess the genetic diversity of Scots pine populations and trees in the steppe region of European Russia.

The effect of drainage on fine‐root biomass, production, and turnover in hemiboreal old‐growth forests on organic soils

AbstractInformation on the capacity of organic soils to capture and store carbon in old‐growth forests in the hemiboreal forest zone is scarce and fragmented. However, fine‐root data can provide valuable insights into soil carbon fluxes. Thus, the aim of the current study was to provide estimates of the fine‐root biomass (FRB), fine‐root production (FRP), and fine‐root turnover (FRT) rate by tree species and other functional groups in old‐growth (stand age 131–179 years) forests on mesotrophic organic soils dominated by Scots pine (Pinus sylvestris L.), with and without the effects of forest drainage. The sequential soil coring method was used to estimate the FRB and FRP. The total FRB was significantly higher in the undrained sites (6.8 ± 0.3 t ha−1) than in the drained sites (3.97 ± 0.1 t ha−1). The FRB of Scots pine in the undrained forest was significantly higher (1.7 ± 0.1 t ha−1) than in the drained forest (0.5 ± 0.1 t ha−1), supporting an extensive foraging strategy. The significantly higher mean FRB of Norway spruce (Picea abies [L.] Karst.) (1.4 ± 0.1 t ha−1) in the drained sites than the undrained sites (0.7 ± 0.2 t ha−1) can be explained by there being a higher proportion of spruce in the stand compositions, thus a higher standing volume of this species and an increased FRB. The FRB of dwarf shrubs (2.43 ± 0.2 t ha−1) formed the largest part of the total FRB in the undrained sites and the second largest (1.16 ± 0.1 t ha−1), following Norway spruce, in the drained sites. The total FRP was similar between the undrained (2.05 ± 0.31 t ha−1 year−1) and drained (1.82 ± 0.26 t ha−1 year−1) stands. However, considerable variability in the FRP was observed between different sites of the same forest site type. The FRT rate of Scots pine was twice as high in the drained sites than the undrained sites, suggesting faster nutrient and carbon input into the drained soil compared with the undrained soil. Estimates of FRB, FRP, and FRT rates for different functional groups can be used in carbon‐cycle modeling and in further calculations to estimate the carbon budget (balance) in forests on organic soils.

Dynamics of radioactive contamination of lingonberry (Vaccinium vitis-idaea L.) in the forests of Zhytomyr Polissia (Ukraine) since the Chernobyl Nuclear Accident

The article presents results of study of levels of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry (Vaccinium vitis-idaea L.) phytomass and berries on permanent experimental plots in different years since the Chernobyl Nuclear Power Plant accident (forest site type conditions — moist fairly infertile pine site type (B3), soils — soddy-podzolic sandy-loam on fluvioglacial sands). The research was conducted at the Poliskyi Branch of the Ukrainian Research Institute of Forestry and Forest Melioration named after G.M. Vysotsky over the years 1998–2021, utilized methods generally accepted in forest science and radioecology were used. Results were processed using statistical analysis. To substantiate the research, an official reporting data from forestry enterprises of the Volyn, Rivne and Zhytomyr regions were used. An analytical review of the state of research on this problem revealed that at the last 10–15 years there were no scientific publications on the study of 137Cs contamination of lingonberry. It was demonstrated that there was significant reduction in the density of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry phytomass and berries in the forests of the research region over the observation period. It was found that the main part of the total 137Cs activity is currently located in the upper (10 cm) layer of the mineral part of the soil — 74.7% where root systems of herbaceous and dwarf-shrub species are concentrated in forest ecosystems. It was established that a considerable content of the radionuclide is retained in the aboveground part of lingonberry phytomass even with low density of radioactive soil contamination. It was found that in 1998, at relatively low value of soil 137Cs contamination density (49±5.6 kBq∙m–2), specific activity of 137Cs in aboveground phytomass of lingonberry was 8043±511 Bq∙kg–1, while in 2021 (value of soil 137Cs contamination density 22±0.3 kBq∙m–2) — 1046±182 Bq∙kg–1. The values of radionuclide transfer coefficients in 1998 were quite significant and varied within wide range: in the air-dry aboveground phytomass from 33.4 to 164.1 m2∙kg–1∙10–3 and in the fresh berries, from 9.5 to 26.0 m2∙kg–1∙10–3. Dependencies between density of radioactive soil contamination and the content of 137Cs in the aboveground part of lingonberry phytomass and berries were calculated, which can be applied in the practice of their harvesting. It was found that lingonberry belongs to the group of plants characterized by the high content of 137Cs in the aboveground vegetative phytomass. Harvesting of lingonberry leaves for the production of medicinal products should be restricted in all areas contaminated with 137Cs. Lingonberry fresh berries can be harvested in areas with a radioactive soil contamination density up to 74 kBq∙m–2.

Carbon stock changes of drained nutrient-rich organic forest soils in Latvia

Impact of drainage of organic soils in forest land on soil carbon (C) stock changes is of high interest not only to accurately estimate soil C stock changes, but also to provide scientifically based recommendations for forest land management in context of climate change mitigation. To improve knowledge about long-term impact of drainage on nutrient-rich organic soils in hemiboreal forests in Latvia, 50 research sites representing drained conditions (Oxalidosa turf. mel. (Kp) and Myrtillosa turf. mel. (Ks) forest site types) and undrained conditions as control areas (Caricoso-phragmitosa, Dryopterioso-caricosa and Filipendulosa forest site types) were selected. Soil C stock changes after drainage was evaluated by comparing current C stock in drained organic soils to theoretical C stock before drainage considering impact of soil subsidence. During the 53-years period after drainage, the peat subsidence was higher in nutrient-rich Kp forest site type compared to moderate nutrient-rich Ks forest site type (peat subsided by 37.0 ± 4.8 and 23.3 ± 4.8 cm, respectively). In nutrient-rich Kp forest site type, soil C stock decreased by 4.98 ± 1.58 Mg C ha–1 yr–1 after drainage, while no statistically significant changes in soil C stock (0.19 ± 1.31 Mg C ha–1 yr–1) were observed in moderate nutrient-rich soils in Ks forest site type. Thus, in Ks forest site type, the main driver of the peat subsidence was the physical compaction, while in Kp forest site type contribution of organic matter decomposition and consequent soil C losses to subsidence of the peat was significant.

Relationship between stand and landscape attributes and Ips typographus salvage loggings in Finland

Disturbances caused by the European spruce bark beetle (SBB; Ips typographus L.) on Norway spruce (Picea abies (L.) H. Karst.), have increased immensely across Central and Northern Europe, and are expected to increase further as a result of climate change. While this trend has been noted in Finland, so far limited research has been published. To support proper SBB risk management in Finland, we compared stand properties between salvage loggings due to SBB damage during 2012–2020 (4691 cases) and spruce stands free of SBB damage. Also, we explored the role of landscape attributes as drivers of SBB damage. We considered the forest stand attributes of site fertility class, stand development class, soil type, stand mean diameter at breast height and mean stand age. Considered forest landscape attributes were the distance from SBB-damaged stands to the closest clear-cut, to previous-year SBB-damaged stands and to the previous-year wind-damaged stand. We used nationwide forest logging and forest stock data, and analysed forest stand attributes using chi-squared and Mann-Whitney U tests and landscape attributes using generalised linear mixed models. Based on our findings, the SBB didn’t damage stands randomly, but prevailed in mature stands (high age and high mean diameter at breast height), in herb-rich heath forest site types and in semi-coarse or coarse heath forest soil soils. We found correlation between the landscape variables and the number of salvage loggings, with a higher number of loggings due to SBB damage close to clear-cuts. Our results help to find risk areas of SBB damage.

Current 137Cs accumulation by mushrooms in different site types of scots pine forests of Ukrainian Polissia

The study of 137Cs radioactive contamination of fruiting bodies of mushrooms was carried out in September - October 2022 in 18 sampling sites laid out in the Korosten district of Zhytomyr region in 3 of the most widespread forest site types (FST): fresh infertile pine site type (А2), fresh fairly infertile pine site type (В2) and moist fairly infertile pine site type (В3). It was found that the highest levels of 137Cs content in investigated FST were characteristic of symbiotrophic mushroom species - Сortinarius mucosus, Сortinarius caperatus, Sarcodon imbricatus, Imleria badia, Tricholoma equestre, Paxillus involutus, Hygrophorus hypothejus, and the lowest - for xylotrophes-saprotrophes such as Armillaria mellea and Tapinella atrotomentosa. When analyzed, it was shown that interspecific differences of average values of 137Cs aggregated transfer coefficient (Tag) among mushrooms in each FST varied in a wide range: they reached 1.1⋅103 times in FST-A2 - from 435 in Cortinarius mucosus to 0.4 m2⋅kg-1⋅10-3 in Armillaria mellea; 71.4 times - in FST-B2 - from 162 in Sarcodon imbricatus to 2.3 m2⋅kg-1⋅10-3 in Armillaria mellea; and 12 times - in FST-B3 - from 111 in Imleria badia to 9.2 m2⋅kg-1⋅10-3 in Leccinum scabrum. Also, it was shown that in genus Russula even in the same FST-B2 among five studied species a 24-fold change in average values of 137Cs Tag are observed - from 67 in Russula vinosa to 2.8 m2⋅kg-1⋅10-3 in Russula aeruginea. The results of ANOVA were discussed as well as the essentiality of the difference of the average values of Tag in mushroom species in different FST.

Viscum album subsp. austriacum (Santalaceae R. Br.) in Volyn Polissia and Zhytomyr Polissia (Ukraine): current distribution, ecology and prediction of future spread

Background. One of the subspecies of the European mistletoe, the so called pine mistletoe (Viscum album subsp. austriacum (Wiesb.) Vollm.) is a hemiparasitic, evergreen, epiphytic phanerophyte that parazitizes predominantely on the Scots pine (Pinus sylvestris L.) in Ukraine. The pine trees infested with V. album subsp. austriacum lack moisture for transpiration and photosynthesis, which reduces their primary productivity, viability and health. The purpose of this study was: 1) to determine the current distribution of V. album subsp. austriacum in Volyn and Zhytomyr Polissia regions using GIS-technology; 2) study the main taxation parameters of pine stands infested with V. album subsp. austriacum; 3) predict the possible further spread of V. album subsp. austriacum in the studied Region. Materials and Methods. The grid mapping method based on GIS technology, with a grid size of 10×10 km and 20×20 km, was used to create the map of the species distribution. The spatial distribution of soil moisture in the forest soils of Drevlyanskyi Nature Reserve was determined using satellite images and data on soil moisture from the Earth Engine Data Catalog. The taxation parameters of the mistletoe-infested pine stand (i.e., participation of the Scots pine in the stand composition, area distribution of pine stands by age, relative completeness, stand quality class, trophotope, and hygrotope) were obtained from standard taxation descriptions. Results and Discussion. The study found that V. album subsp. austriacum is more widespread in Volyn Polissia than in Zhytomyr Polissya – 87 and 20 localities respectively. It was shown that the forest plantations colonized by V. album subsp. austriacum in Drevlyansky Nature Reserve are located in areas with the lowest moisture content, with a moisture reserve of 16–70 mm in the 0–100 cm soil layer, which corresponds to dry and fresh hygrotopes. Conclusions. V. album subsp. austriacum is more widely distributed in such nature reserves of the region as Shatskyi National Nature Park and Drevlianskyi Nature Reserve, and less so in Rivne, Cheremskyi, Polissia Nature Reserves and Pripyat-Stokhid National Nature Park. In the region under study, V. album subsp. austriacum mostly affects pure pine forests aged 80‒140 years, of medium completeness (0.5‒0.7), and relatively high and high stand quality classes – Ic–II, in fresh hygrotopes – 67.3 % of the area and in fairly infertile pine site type (trophotope B) – 51.5 %. Based on the distribution of forest site types in the region and their susceptibility to V. album subsp. austriacum, the possibility of its further intensive spread in the study region can be predicted.

Maintaining the protective function of mountain forests under climate change by the concept of naturalness in tree species composition

In Swiss mountain areas, the protective function of forests is the predominant ecosystem service having high cultural and economic significance. It is assumed that natural forests or close-to-natural forests, i.e., forests being in the equilibrium with environmental conditions are the most resilient and resistant in regard to disturbances and hence best protecting people and assets on the long run. Here, we estimated the naturalness of the tree species composition by comparing Swiss National Forest Inventory (NFI) data with current and future potential Natural forest Site Types (NST). Based on this analysis, we identified species that are under or over-represented in protective mountain forests and derived the subsequent potential for management interventions. The urgency of management interventions is expected be small if all predominant tree species of the idealized potential natural forests are present and only their relative portions in the stand need adjustment. In contrast, interventions are advisable, if predominant tree species of the current and future potential natural forests are absent. Based on NFI data, the tree species composition of 47% of the protective mountain forests were classified as “natural” or “close-to-natural,” while the remaining 53% were classified as “not natural” or “partly natural.” Norway spruce [Picea abies (L.) H. Karst.] and European larch (Larix decidua Mill.) were the two most over-represented species under current and even more so under predicted future climatic conditions. To date, silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) were the two species most frequently absent in protective mountain forests, in which they should prevail. Apart from European beech, the most prominent increase in prevalence is predicted for oak (sessile oak and pubescent oak; Quercus petrea Liebl., Q. pubescens Willd.) and small-leaved lime (Tilia cordata Mill.). These species were currently missing from more than 75% of the stands, in which they are expected to be dominant under future conditions. Our analysis indicates the need to transform tree species compositions of protective mountain forests to optimize fitness under future climates. Some of these transformations will take place naturally, incited by disturbances, others—the majority of them—will need active management interventions.

Input data resolution affects the conservation prioritization outcome of spatially sparse biodiversity features.

Detailed spatial data are an essential part of land use planning and decision-making. Their spatial resolution sets limitations to their use, as coarse datasets are not suitable for detecting small-scale phenomena. In this study, we explored the effects of spatial resolution on the ecological outcome of a conservation prioritization process in Zonation software. Our study area was in Evo, southern Finland, covering a mosaic of managed and conserved forests. We produced the feature layers describing the forest characteristics using high-resolution remote sensing datasets, object-based mapping methods, and forest site type data. We found that increasing the resolution above the 16 m baseline resolution resulted in substantial errors. The conservation errors were the highest for rare features related to European Aspen, whereas the common features related to dominant tree species could benefit from the growth of cell size. We conclude that adequate spatial resolution is a prerequisite for efficient conservation prioritization, and that the size and spatial distribution of the features affect the resolution requirements.

High acorn diversity of the introduced Quercus rubra indicates its ability to spread efficiently in the new range

The morphological traits of seeds have a fundamental meaning for spread and regeneration of non-native zoochorous plants, as they determine the level of establishment success and the ability of native fauna to disperse the alien plant. Here we studied the size, mass and viability of acorns of the North-American northern red oak Quercus rubra in its introduced range (in central Poland). The study revealed that acorns sampled in 2018 and 2019, in Q. rubra stands which had just reached sexual maturity, achieved optimum age for seed crop production, or were close to the rotation age, and were planted in sites suitable to European coniferous, mixed, and deciduous forests, differed in their dimensions and weight. Acorn size, mass and viability were affected both by stand age and forest site type, but more strongly by the first factor, i.e. the older the stand, the larger the acorns. At the initial stage of reproduction larger acorns were produced in coniferous than in other forest sites, but this advantage decreased with the age of stand in favour of more fertile mixed and deciduous forest sites. Acorn dimensions and viability also differed in sequential years: larger acorns with a high proportion of viability were produced in 2018, while in 2019 the proportion of viable acorns was significantly lower. The moisture of (viable) acorns was well above the lethal level for most acorns in all stands studied, however, it was impacted by the autumn weather.The high intraspecific variability in size and weight makes Q. rubra acorns attractive for different species of native seed hoarders. It conditions effective acorn spread and regeneration of this introduced (invasive) oak in European forests. Therefore, leaving single oak trees over 90 years old – which produce the best quality seeds – on plots cleared during forestry operations can favour Q. rubra regeneration.

Natural afforestation of the fallows in the Western Polissya

One of the main tasks of forestry in Ukraine is to increase forest cover – it can be partially solved by the development of low-productive agricultural land, in particular, fallows, on which self-sown forest is already growing or just appearing, since the expanded reproduction of forests is relevant for Ukraine, considering ecological and forestry transformations of fallows conditioned by their natural afforestation. The main goal was to evaluate the success of natural renewal on fallows in the region under study, to identify factors influencing the course of natural afforestation and tree conservation depending on the location of the plot relative to the forest border and the distance to it. General scientific, forestry and taxation, reconnaissance, forestry and ecological, and geobotanics methods were used to investigate natural renewal at fallows. Office study of materials was carried out using mathematical statistics. As a result of a detailed investigation of the natural settlement of forest tree species on abandoned fields of Western Polissya, it was found that in coniferous and subor conditions, the plots are mostly wooded with pine, as well as birch and alder. In most of the test plots, the renewal was satisfactory (according to the Nesterov scale). The number of self-seeding of tree species in the test plots was not uniform and ranged from 1.2-13.1 thous. units/ha depending on forest site types, species composition, undergrowth size, the abundance of living ground cover, and the degree of sodding of the site and clogging with weeds and grass, which ranged from 20 to 90%. The occurrence of natural renewal is also not uniform: from 19 to 100%. The spread of tree species occurred mainly from forest stands located to the west, northwest, and north of the fallows. The findings of the study are extremely important for employees of the forest industry, and can also be used by territorial communities in improving land management, establishing landscape parks, etc.

Eesti sürjametsad; nende tüübid ja indikaatorliigid

Abstract The aims of the study were: (i) to examine how well the hillock forests are distinguishable from the forests of comparable site types, (ii) to ascertain the hillock forest indicator species, (iii) to elucidate the hillock forests’ community types, (iv) to assess the practical requirement for differentiation of hillock forests as a self-sufficient typological unit for forestry. The data included altogether 160 descriptions of hillock forest communities and 42 relevés of other site type stands for comparison. The historical continuity of hillock forests was estimated from old topographic maps. We established that the hillock forests constitute statistically a reliable distinct group of forests. Among the characteristic species having an indicator value significance level of up to 0.50, by the ecological strategy 43.2% belong to competitors, 37.8% are competitors and stress-tolerant ruderals, and 10.8% competitors and stress tolerators; according to the hemeroby, 62.5% of these species are apophyts and 30.0% hemeradiaphors. Most hillock forests (55.6%) are located on former slash-and-burn areas (bushlands) or reforested agricultural land (36.1%). The hillock forests can be classified into four forest types: 1) Fragaria vesca–Festuca ovina–Pinus sylvestris type, 2) Fragaria vesca–Oxalis acetosella–Pinus sylvestris type, 3) Fragaria vesca–Viola mirabilis–Picea abies–Populus tremula type and, 4) Fragaria vesca–Equisetum pratense–Betula pendula type. There is no need to define the hillock forests as a separate forest site type in practical forest typology, nevertheless recognition of these forests as representing the habitat directive type 9060 is important from the viewpoint of biodiversity maintenance.

Stem volume by height classes of immature, mature and overmature stands of the main forest-forming species of Ukraine

Generally, it is impossible to measure diameters and heights of all trees in a forest stand. Therefore, models of relationships between heights (h) and diameters (d) of trees are commonly used in practice for stem volume estimation. This study aimed at developing models of tree height-diameter (h-d) relationships as well as corresponding models of the tree stem volume for immature, mature and overmature stands of the main forest-forming species of Ukraine. This paper is a aggregation of long-term studies of the stem volume, which are based on the results of measuring about 10 thousand sample trees. Modelling of the tree height-diameter relationships was performed using relative height values. The methodology used in this study allowed generalising the measurements of sample trees collected in stands of various forest site types, productivity levels, and age categories. The average height of trees with a diameter of 24 cm was taken as the reference during modelling relative heights, while the diameter of 40 cm was chosen as the reference for overmature Scots pine stands. As a result, the parameters of a unified mathematical model of relative heights for immature, mature, and overmature stands of the main forest-forming tree species of Ukraine were established. Based on these models, height-diameter relationships in forest stands of different height classes were predicted. The authors demonstrated that the developed mathematical models substantially simplify the methodology of field work during timber surveys. The paper also presents models of the tree stem volume. These models predict the stem volume outside the bark based on diameters and heights of trees or using the developed models of h-d relationships. In this study, a unified system of mathematical models of stem volume by height classes were created for immature, mature, and overmature stands of the main forest-forming species of Ukraine. The results of the study are introduced to the National Forest Inventory of Ukraine for growing stock volume calculation at sample plot level using measurements of individual trees. The developed models can be used both by operation forestry (estimation of the timber volume during harvesting), and forest management (forecasting the future structure of forests and estimating the growing stock volume), as well as in the forest ecology

Variation in aboveground biomass carbon accumulation in Scots pine seed orchards progeny

Increasing growth and biomass accumulation in forest stands may positively contribute to carbon (C) sequestration and climate change mitigation. Tree improvement programs develop planting material with enhanced growth and biomass accumulation. Scots pine is commonly planted in Europe, and provides a potential for increased C accumulation in forest biomass when using improved seed origins. Our objective was to investigate variation in standing aboveground C accumulation among the progeny of Scots pine seed orchards in climatically variable environments, where we also compared the amount of accumulated C between the tested populations and commercial stands. The aboveground biomass of trees in two series of replicated common garden trials was estimated with eight allometric equations, converted into C, and expressed per unit area. For each trial site we selected reference stands matching the age, stand composition and forest site type, where the same measurements and calculations were done on sample plots. We specifically expected to find the progeny that would express better growth and greater accumulation of C in their biomass when compared to the reference stands. Significant and large variation was found among the examined seed sources and trial sites. On average, aboveground C accumulation varied among sites from 31.0 to 60.4 Mg ha-1 (age 22) and from 25.5 to 34.0 Mg ha-1 (age 17). Differences between populations at individual sites ranged from 41% to 55% (age 22), and from 29% to 54% (age 17). However, only a few of the investigated progeny had C accumulation significantly greater than the reference stands, and some had a lower C accumulation, depending on the study site. This study for the first time quantifies the amount of and variation in aboveground C accumulation among the progeny of Scots pine clonal and seedling seed orchards in Poland. It also contributes to the knowledge of the patterns of within-species variation in growth and biomass accumulation. Variation we found is promising for the potential to enhance C sequestration in forest stands through tree improvement. However, the lower C accumulation or non-significant differences between research trials and reference stands, indicate that the level of growth enhancement from phenotypic selection practiced so far in Polish forestry is limited. For increased C sequestration in planted forests, selection would need to be intensified.

Role of forest site type in determining bacterial and biochemical properties of soil

• The biological properties of the soil are determined by the site type. • The tested soils are significant differences in microbiological activity. • Soil from fresh mixed boron is the most fertile soil. The aim of the present study was to investigate the effect of forest site type on the bacterial and biochemical properties of the soil. Data for counts, diversity, and composition of bacterial communities, as well as soil enzymatic activity, was used for the assessment. A determination of the relationships between the parameters was also performed. Soil samples were collected in the Stare Jabłonki Forest Division (north-eastern Poland, Central Europe) from four sites: fresh coniferous forest (Fc), fresh mixed coniferous forest (Fm), fresh mixed forest (Mf), and moist mixed forest (Mm). The tested soils showed significant differences in enzyme activity and microflora. Organotrophic bacteria and actinobacteria proliferated the most in soil from fresh mixed coniferous forest. Organotrophic bacteria grew faster than actinobacteria in the soil, indicating that the former were represented by r-strategists, and the latter – by K-strategists. The soil sampled from site Fc2 (fresh coniferous forest) had the highest values of the diversity index. Alphaproteobacteria (phylum Proteobacteria ) were the dominant bacterial class in the soils, followed by Actinobacteria (phylum Actinobacteria ) and Acidobacteriia (phylum Acidobacteria ). Phyla Proteobacteria , Actinobacteria, and Acidobacteria were most abundantly represented by genera Rhodoplanes, Mycobacterium , and Candidatus Solibacter , respectively. According to the biochemical soil quality index (BA), the soil sampled from site Fc2 (fresh mixed coniferous forest) was the most fertile. The study demonstrates that microbial and biochemical parameters of the soil can serve as an accurate indicator of the status and health of forest ecosystems.

DEVELOPMENT OF YOUNG STANDS AFTER WHOLE TREE HARVESTING AND WHOLE TREE HARVESTING COMBINED WITH STUMP BIOMASS EXTRACTION

Forest management pressures on ecosystems are expected to rise due to increased use of renewable resources and environmental, economic and political reasons. Extraction of nutrient rich logging residues from felling sites has become a common practice, therefore risks of negative impact on the nutrient cycling as well as site future productivity must be assessed. To evaluate effect of whole-tree harvesting (WTH) and whole-tree harvesting combined with stump biomass extraction (WTH+SB) on productivity of next rotation young stands measurements were carried out in eight sites for four to six years in typical forest site types in Latvia (Oxalidosa turf. mel. – eutrophic peat soil site; Hylocomiosa, Oxalidosa – mesotrophic mineral soil sites, Mytrillosa – oligotrophic mineral soil site). Harvesting in the sites was carried out in 2012-2013 and regeneration was carried out after one to two years with Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. (Karst.)) and black alder (Alnus glutinosa L. (Gaertn.)). Comparing conventional harvesting or so-called stem only harvesting (SOH) to WTH no statistically significant differences were observed regarding tree height, but in eutrophic Norway spruce site WTH plot smaller stem diameters were observed. Comparing WTH to WTH+SB statistically significantly higher Norway spruce and black alder heights in mono-stands were observed in WTH plots, while no significant differences were detected in Norway spruce and black alder mixed stand. No explicit differences were found regarding height/diameter ratio between WTH and WTH+SB treatments.

PINUS SYLVESTRIS L. REGENERATION FROM SEED TREES IN VACCINIOSA AND MYRTILLOSA

Scots pine (Pinus sylvestris L.) is an economically important tree species in temperate forests, including Latvia. Purposeful selection work has resulted in the provision of faster-growing planting material for forest planting. Natural restoration initially requires less investment, it has several disadvantages. When using this method, it must be considered that the forest stands will have an uneven species composition, the age and height of the trees will differ. The study was carried out in young naturally regenerated stands in Vacciniosa and Myrtillosa forest site type and compared with planted stands The aim of the study was to evaluate the natural regeneration and last 5 year tree height increment of Scots pine regenerated from the seed trees in the Vacciniosa and Myrtillosa, compared to planted stands, as well as to assess the impact of tree health on pine height increment. In total 10 young stands were surveyed, 66 sample plots were established and 704 trees were measured. The area of the temporary sample plot was 25 m2 with a radius of 2.82 m. Comparing the annual height increases of Scots pine, both in naturally regenerated and planted young stands in Vacciniosa and Myrtillosa, it was found that there are statistically significant differences between forest types, stand origin type, as well as in existing stands in the last 5 years by years (p <0.05). The most significant damage to young pine stands is caused by needle cast, ungulates, and large pine weevil.

Effect of growth conditions on wood properties of Scots pine (Pinus sylvestris L.)

Abstract The study material of Scots pine sample trees originated from five different forest site types (Cladonia, Calluna, Myrtillus, natural raised bog and drained raised bog) in Estonia. Altogether, 60 trees were sampled from 10 stands. From these, test disks and sample blocks (1.2 m in length) were cut at 1.3 m height, 1/2 of tree height and 3/4 of tree height. We analysed the effect of forest site type on the growth of tree ring width, proportion of late- and heartwood, oven-dry density, bending and compression strength and wood hardness. Wood properties in stands of the same age showed great variability. Significant differences were found in the wood properties between site types. Wood density and strength characteristics were higher in samples from heath site types than from the sites more optimal for pine (e.g., Myrtillus). The quality of the wood from peatland stands was lower than from trees grown on mineral soil. The decreasing trend in strength properties towards the top of trees was steeper in the wood formed under poor nutrient conditions. Latewood proportion increased with tree age. However, in the case of equal latewood percentages, heartwood density was higher than sapwood density.