Forest Site Types Research Articles

The Effects of Natural and Economic Factors on the Financial Performance of Forest Management Units: The Example of Forest Districts of the State Forests National Forest Holding from Eastern Poland

Given the changing market conditions and uncertainty arising from climate change, forest management tends to focus on the financial functioning of forest holdings. The objective of this work is to study the financial performance of forest districts using ratio analysis, synthetic financial indicators, as well as the relationship between synthetic indicators and forest district categories defined in terms of forest site type, site fertility, compatibility stand species composition, species composition, harvesting system, harvesting intensity, fragmentation of forest complexes and management difficulty level. The study material consists of financial documentation from 82 forest districts of the State Forests National Forest Holding (SFNFH) in eastern Poland from the years 2015–2019 and 2005–2009 (for comparison purposes). Synthetic indicators were calculated using two sets of financial ratios as well as two variants of accounting data. In the study period, forest districts were found to differ in terms of their financial performance, which was affected by the natural and economic factors. The synthetic indicators were significantly higher (p > 0.05) for forest districts operating on low-fertility lowland sites, those managing stands with dominant pine, and those implementing a clearcutting regeneration system. The findings concerning the effects of selected natural and economic factors on the financial condition of forest districts may be used for financial planning and management by SFNFH, in particular in decision-making processes to optimize forest management. The applied methods may stand as a basis for the construction of a sectoral evaluation tool.

Participatory modelling of upward shifts of altitudinal vegetation belts for assessing site type transformation in Swiss forests due to climate change

AbstractAimsClimate change is expected to markedly change site factors, tree species composition and finally ecosystem services provided by forests. Here, we describe the development of a framework for modelling how these changes may transform forest site types. Site types capture information on site conditions like climate, topography and soil, all factors with strong influence on tree species occurrence.LocationSwitzerland.MethodsWe elicited expert knowledge and followed a participatory modelling approach for quantifying upward shifts of altitudinal vegetation belts and the changes in the zonal distribution of main tree species, as a basis for assessing transformation pathways of forest site types for three climate projections.ResultsThe model results show marked range shifts of altitudinal vegetation belts. The change in the vegetation belt and a rule base for forest site type transformations allow for assessing the location‐specific and long‐term transformation pathway from the current to a future forest site type.ConclusionsThe resulting maps enable forest managers to take climate change into account when selecting tree species. The presented method complements statistical distribution models as it considers more site information, integrates expert knowledge and is based on a forest site type classification which is already widely used by forest practitioners.

Litter and microclimate controls on soil heterotrophic respiration after converting seasonal rainforests to rubber plantations in tropical China

Land-use changes can alter carbon cycling. Soil carbon loss resulting from the conversion of natural forests to rubber plantations (RP) may occur due to changes in litter inputs or in biotic and abiotic environmental conditions. In this study, we conducted a reciprocal soil and litter translocation mesocosm experiment for 15 months in a seasonal rainforest (SR) and RP to elucidate the effect of litter, soil and site conditions on heterotrophic respiration and its temperature sensitivity after land-use conversion. We found that rate of soil heterotrophic respiration (Rh) was higher at RP site than at SR site or for SR litter than RP litter with significant interactions between forest site and litter type, and did not differ between SR and RP soils. The Q10 values of Rh did not differ between forest sites, soils, or litter types but were substantially lower when litter was absent and substantially higher when RP soil was incubated in SR site and vice versa. Removal of surface litters led to a reduction of Rh by 27-45%. Soil labile organic C pool and microbial biomass were not influenced by litter type or forest site, but were influenced by soil origin, with higher values for SR soil than RP soil. Soil temperature and moisture were not influenced by litter type and soil but differed between forest sites with higher moisture at RP site than SR site. Our results suggested that changes in physical environmental conditions, rather than changes in litter input or soil biochemical properties, attributed to the elevated soil heterotrophic respiration in RP, resulting in soil carbon loss following the tropical land-use changes.

Structural Characteristics of the Main Resinous Stands from Southern Carpathians, Romania

The purpose of this study, which contains historical data recorded over a period of 40 years, was to identify the main factors that influence and control the level of wood mass production. The main reason was to optimize the management of forest areas and was driven by the necessity to identify factors that can influence most of the volume produced by coniferous forests located in southeast Europe. The data was collected between1980 and 2005 at the National Institute for Research and Development in Forestry, for forests located in the Southern Carpathians, Romania. The studied data refer to the parameters that model forest structure for spruce, fir, pine, and larch. These are the main resinous species found in the Southern Carpathians. The total area covered by these forests is 143,431 ha. At the forest species level, the analysis consists of 16,162 records (corresponding to the elements of the trees), covering an area of 45,008 ha for fir, 4711 ha for larch, 81,995 ha for spruce, and 11,717 ha for pine. The aim of this research has been to investigate and to assess the impact and magnitude of abiotic factors such as altitude and field aspect on forest structures from the main resinous stands located in the Southern Carpathians. Taking into account the size of the database as well as the duration for collecting data, a complete statistical and systematic approach was considered optimum. This resulted from our wish to emphasize and evaluate the influence of each analysed factor on the wood mass production level. The relationship between abiotic factors and forest structure has been analysed by using a systematic statistical approach in order to provide a useful theoretical reference for the improvement of forest management practices in the context of multiple climatic, environmental, and socio-economic challenges. These common characteristics have been found by applying ANOVA and multivariate statistical methods such as PCA and FA methods. A series of parameters were considered in this investigation, namely altitude (ALT), forest site type (TS), forest type (TP), consistency (CONS) etc. In order to obtain a complete image, we have also applied multivariate analysis methods that emphasize the effect size for each database parameter. At such a level of recorded data, the statistical approach ensures a factor level of p <0.001 while the accuracy in evaluating effect size is increased. As such, they influence the spreading and structure of the studied resinous stands to a higher degree, regardless of species.

Биометрические характеристики посадочного материала как тест-показатель успешности культур Pinus silvestris L.

The creation and cultivation of artificial plantations of conifers largely depends on the planting material quality. The paper is devoted to the study of the relationship between the main parameters of planting material of Scots pine (Pinus silvestris L.) with inventory indices of artificial plantations. Forest trials of Scots pine in the Arkhangelsk region, created in a haircap-moss forest site type, were investigated. Seedlings of Scots pine with standard size were divided into large, medium, small according to the diameter of the root cervix in order to set the experiment, which aimed to determine the relationship between the parameters of planting material and characteristics of the forming plantations. The research purpose determined the main task, mainly, to find out from which plants the “trees of the future” (fast-growing large specimens) are laid out. Plants grown from the large seedlings are characterized by the greatest height. This position, in relation to individuals formed from medium and small planting material, is maintained and gradually increases. From the initial phases of development, a kind of mobile equilibrium is established in the studied plantation. All the trees are growing at a very fast rate, but the initial (at the time of planting on the silvicultural area) size of the planting material corresponding to the pine plants that survived in different years on the plantations continues to remain constant. It was found that, the largest number of leaders (47 % of all survived seedlings) grew of the large seedlings by the end of the 2nd age class. Therefore, high-quality soil treatment together with the use of high-quality proportionally developed planting material significantly increases the inventory indices of plants in the stand, and allows getting the target assortments15–20 years earlier.

A CASE STUDY OF THE APPLICATION OF HAND-HELD MOBILE LASER SCANNING IN THE PLANNING OF AN ITALIAN FOREST (ALPE DI CATENAIA, TUSCANY)

Abstract. Precision forestry is becoming a key sector for forest planning because it allows complex analyses of forest data to be carried out simply and economically. It contributes to the integration between technicians and operators in the sector by guaranteeing the transparency of the forest management operations (Corona et al., 2017). In the context of the progressive development of technology, we investigated the feasibility of using the hand-held mobile laser scanner (HMLS) system in different types of forest sites and comparison of the characteristics of individual trees (tree height, diameters at breast height) with traditional surveys, applied with the aim to validate the performance of the system for a future alternative methodology for forest planning thanks to the collaboration with the forestry company “Dimensione Ricerca Ecologia Ambiente Italia” (D.R.E.Am. Italia). GEOSLAM ZEB HORIZON ™ laser scanner is a hand-held mobile laser scanner containing SLAM technology that can be solved the problem of no GNSS signal or poor signal under the forest canopy making it more practical for forest investigations (Gollob et al., 2020). 15 forest sample plots are selected to reflect different stand conditions in Mediterranean forests taking into count the development stage and density of the sub-canopy vegetation, as well as the species composition in the forest stands. The aim of this study is to show the possible extrinsic circumstances that make the method fail by varying the ecological status of forest plots.

Evaluation of Soil Organic Layers Thickness and Soil Organic Carbon Stock in Hemiboreal Forests in Latvia

In the forest land of many European countries, including hemiboreal Latvia, organic soils are considered to be large sources of greenhouse gas (GHG) emissions. At the same time, growing efforts are expected in the near future to decrease emissions from the Land Use, Land Use Change and Forestry sector, including lands with organic soils to achieve enhanced contributions to the emissions and removals balance target set by the Paris Agreement. This paper aims to describe the distribution of organic soil layer thickness in forest land based on national forest inventory data and to evaluate soil organic carbon stock in Latvian forests classified as land with organic soil. The average thickness of the forest floor (organic material consisting of undecomposed or partially decomposed litter, O horizon) was greatest in coniferous forests with wet mineral soil, and decreased with increasing soil fertility. However, forest stand characteristics, including basal area and age, were weak predictors of O horizon thickness. In forests with organic soil, a lower proportion of soil organic matter layer (H horizon) in the top 70 cm soil layer, but a higher soil organic carbon stock both in the 0–30 cm layer and in the 0–100 cm layer was found in drained organic soils than in wet organic soils. Furthermore, the distribution of the soil H horizon thickness across different forest site types highlighted the potential overestimation of area of drained organic soils in Latvian forest land reported within the National GHG Inventory.

TYPOLOGICAL STRUCTURE OF FORESTS IN THE DESNA CATCHMENT AREA

A general characterization of the catchment area of the River Desna is given. The Desna catchment area is located in two forest zones of Ukraine - Polissia, and Lisostep. According to the results from the analysis of the forest inventory database of PA Ukrderzhlisproekt, the planted areas of the Desna catchment area have been distributed by forest site types, forest types, tree species. To analyze the typological structure of the Desna catchment area, the sites belonging to the catchment area have been selected from the standwise forest inventory database of PA Ukrderzhlisproekt. The total area of the stand sample is 395.3 thousand hectares. The catchment area boundary has been determined using MapInfo Professional 12.5 and a vector map of Ukraine. The forest areas are distributed by administrative regions as follows: Chernihiv Region (62 %), Sumy Region (31 %), Kyiv Region (7 %). The forest resources of the Desna catchment area are characterized by a wide variety of types of forest sites covering almost the entire Ye.V. Alekseev’s and P.S. Pogrebnyak’s edaphic grid. In each group of forest site types, the foresters have identified different numbers of forest types. Pine forests (bors) are represented by five, pine – fir/oak forests (subors) - by eight, pine forests with birch, aspen and oak participation (composite subors) – by twenty eight and oak groves (dubravas) – by eighteen types of forest. In total, 59 types of forest are identified, including four - arid, thirteen - fresh, eighteen - sodden, nineteen - wet and five - bog. The most common types of forest within the area of the study subject are as follows: fresh fir/oak forest (subor) (40 %), fresh lime/oak/pine forest (composite subor) (9 %), sodden fir/oak forest (subor) (7 %), fresh pine forest (bor) (7 %). Among the tree species, the following species predominate common pine (60 %) and common oak (15%). The weighted average forest inventory indicators of natural and artificial pine forests in the conditions of fresh oak/pine forest (subor) in the Desna catchment area have been determined and analysed. It has been established that natural pine forests, as pertaining to reserves (per 1 m3•ha-1) up to the 5th age class, predominate over artificial pine forests, and, in contrast, as for the 6th to the 13th and further age classes, the artificial pine forests predominate over the natural ones. While planning, organization, and forest management in compliance with watershed and landscape principle, one should take into account the following varieties: forest types, types of forest stands, categorization of forest protectability in the watersheds of Desna River.

The structural complexity index SCI is useful for quantifying structural diversity of Estonian hemiboreal forests

Comprehensive description and quantification of stand structure is needed for managing or maintaining forests as complex systems. The tree position and diameter based structural complexity index SCI was used to quantify the structural heterogeneity of forest stands in Estonia. The aims of the study were to determine if SCI is related to the conventional stand characteristics used for forest management planning and to assess the direct impact of silvicultural treatments on stand structural heterogeneity. The SCI for hemiboreal forests in Estonia ranged from 1.36 to 10.78, being highest in conservation forests on fertile sites (7.42 ± 1.20), followed by managed forests on fertile sites (4.74 ± 1.44), managed forests on poor sites (4.00 ± 1.02), conservation forests on poor sites (3.85 ± 0.87), and lowest in rehabilitation forests (2.64 ± 0.69). The mean SCI between forest groups and site types differs significantly, except in managed and protected forests growing on poor sites. The SCI is positively associated with commonly measured stand characteristics, indicating that stand structural heterogeneity reflected in SCI is higher for older stands with larger trees, higher deadwood quantity and biomass. The results also show that species diversity promotes stand structural diversity. SCI is a promising method for providing quantitative assessments of multidimensional forest stand structure in Estonia.

Evaluation of silver birch diameter increment model based on data of the Czech National Forest Inventory

In the Czech Republic, the silver birch (Betula pendula Roth.) is considered as a pioneer and a soil preparing tree species. It occurs mainly on clearcutting areas after disturbances. The aim of this study was to fit breast height diameter increment model for birch with respect to tree age, share of birch trees and forest site type (ecological series – ES and forest vegetation zones – FVZ). We used data of both cycles of National Forest Inventory of the Czech Republic. We evaluated production potential of this species. We tested Korf and Michailoff increment models in variant of nonlinear least squares model (NLS) and nonlinear mixed effects model (NLME). Michailoff models performed better. We found seven statistically significant and practically applicable models. The greatest influence on increment of diameter at breast height have forest vegetation zone and ecological series whereas the influence of the share of birch in forest stand is smaller. The highest absolute values of diameter increment were on gleyed or enriched with water sites in the fourth forest vegetation zone.

Сучасний стан дубових насаджень на притоках Ворскли у межах Сумської області та особливості їхнього природного відновлення

Подано результати досліджень щодо характеристики дубових насаджень на притоках Ворскли у межах Сумської області. Визначено, що серед загальної площі вкритих лісовою рослинністю лісових ділянок на водозборі Ворскли (40464 га), найпоширенішими є дубові насадження, частка площі яких становить 64,4 % (26052 га). Проаналізовано розподіл площі цих насаджень на 10 притоках річки Ворскли за типами лісорослинних умов, походженням, класами віку та категоріями лісів. Наведено результати досліджень природного поновлення дуба й інших порід під наметом дубових насаджень і на зрубах. Підтверджено необхідність сприяння природному відновленню й ефективного його використання для відтворення дубових лісів на водозборах річок. Розподіл дубових насаджень за типами лісорослинних умов свідчить про сприятливі умови для їх росту, оскільки 90,7 % площі становлять свіжі груди. Вікова структура досліджуваних дубняків є розбалансованою. Переважають насадження IX–XII (52,4 %) та V–VIII (35,5 %) класів віку. Природні дубові ліси займають 58,3 % (15185 га) від загальної площі, а штучні (лісові культури) – 41,7 % (10867 га). Розподіл дубових насаджень за функціональним призначенням свідчить про переважання експлуатаційних лісів, частка яких становить 53,7 % (14001 га) від загальної площі. Частка захисних лісів становить 36,1 % (9387 га), лісів природоохоронного, наукового, історико-культурного призначення – 7,1 % (1856 га) та рекреаційно-оздоровчих лісів – 3,1 % (808 га). Ці ліси, окрім задоволення потреб суспільства в цінній дубовій деревині, виконують також надзвичайно важливі та різноманітні еколого-захисні функції. Закономірності поширення дубових насаджень на притоках Ворскли доцільно враховувати під час ведення лісового господарства з метою збереження їхнього різноманіття та посилення виконання ними важливих екологічних, захисних, рекреаційних і інших функцій. Окрім цього, особливості їхньої лісівничо-таксаційної й типологічної структури можуть бути враховані для удосконалення відповідних положень водозбірно-ландшафтного районування України.

Site types revisited: Comparison of traditional Russian and Finnish classification systems for European boreal forests

AbstractQuestionsForest classifications are tools used in research, monitoring, and management. In Finland, the Cajanderian forest site type classification is based on the composition of understorey vegetation with the assumption that it reflects in a predictable way the site's productive value. In Russia, the Sukachevian forest classification is similarly based on understorey vegetation but also accounts for tree species, soil wetness, and paludification. Here we ask whether Cajander's and Sukachev's forest types are effectively the same in terms of species composition, site productivity, and biodiversity.LocationBoreal forests on mineral soils in Finland and the Russian part of Fennoscandia.MethodsWe use vegetation and soil survey data to compare the Cajanderian and the Sukachevian systems in terms of the understorey community composition (that is supposed to define them), soil fertility and tree productivity (that they are expected to indicate), and biodiversity (that is of interest for conservation purposes). We create and employ class prediction models to divide Russian and Finnish sites into Cajander's and Sukachev's types, respectively, based on vegetation composition. We perform cross‐comparisons between the two systems by non‐metric multidimensional scaling ordination and statistical tests.ResultsWithin both systems, the site types formed similar, meaningful gradients in terms of the studied variables. Certain site types from the two systems were largely overlapping in community composition and arranged similarly along the fertility gradient and may thus be considered comparable.ConclusionsThe Cajanderian and the Sukachevian systems were both developed in the European boreal zone but differ in terms of the exact rules by which site types are determined. Our results show that analogous types between the systems can be identified. These findings aid in endeavours of technology and information transfer between Finnish and Russian forests for the purposes of basic or applied ecological research and forest management.

Транспорт, распределение и потребление 14С -ассимилятов у сосны и ели в северотаежных фитоценозах при различном световом и азотном питании

A rational system of cuttings, mineral nutrition of plants, and preservation of softwood undergrowth during felling is one of the ways to increase the productivity of boreal forests. The physiological methods of research used in forestry and, first of all, the study of donoracceptor interactions, allow obtaining the necessary information on the efficiency level of forestry measures in the stands of pine and spruce undergrowth quickly enough (within 1–2 years) without waiting for the final result in the form of an increment in shoots. The dynam ics of accumulation, transportation and distribution of 14C in organs and tissues of a tree under the influence of selective cuttings and a nitrogen dose has been studied in spruce and pine undergrowth in stands of different species composition and age. The study objects have been: blueberry spruce and birch forests of the forest site types with varying intensity of cutting; lichen pine forests formed from pine undergrowth preserved during the cutting. It were found that, in the summer period under the canopy of spruce and birch forests, the illumination does not exceed 8–10 % of the open area and does not correspond to the biological norm for spruce. The lack of solar radiation and soil nitrogen in the undergrowth of these tree species leads to a decrease in the intensity of photosynthesis and the violation of donoracceptor bonds, delays evacuation of assimilates from a leaf and their transportation to the active zones, suppresses the growth activity and the associated with it “demand” for macronutrients sent to the leaves declines the vitality of plants. The efficiency of the root system deteriorates, the formation of a new assimilation apparatus is delayed, and the growth processes of vegetative organs are violated due to the lack production of assimilates and the disruption of their distribution system. Nitrogen introduced into the stands and selective cuttings in pine and spruce undergrowth activate the synthetic and absorption activity of the root system, improve the functioning of the assimilation apparatus, strengthen the donoracceptor interactions between the aboveground and underground organs of a tree, significantly accelerate the outflow of photosynthetic products from a leaf, and positively influence on the growth processes. It has been found that, according to the level of activity of the donor-acceptor system for the pine and spruce undergrowth, it is possible within 1–2 years to set up a system of felling and a dose of nitrogen introduced into the forest stands that most closely meet the needs of these species. For citation: Konovalov V.N., Zarubina L.V. Transport, Distribution and Consumption of Pine and Spruce 14C-Assimilates in Northern Phytocenoses under Different Illumination and Nitrogen Nutrition. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 4, pp. 77–94. DOI: 10.37482/0536-1036-2020-4-77-94

Вплив кореневої губки на ріст, структуру та санітарний стан соснових насаджень, створених на староорних землях у Лісостепу Харківської області

Одним із найнебезпечніших збудників хвороб хвойних лісів є коренева губка (Heterobasidion annosum (Fr.) Bref.). Всихання насаджень, уражених кореневою губкою, відбувається нерівномірно, тому їх можна умовно розподіляти на фрагменти, що мають різні стан, лісівничо-таксаційні показники та швидкість росту: осередок всихання, міжосередковий простір та еталонна частина міжосередкового простору. Встановлено, що за розподілом кількості стовбурів за ступенями товщини різні фрагменти уражених кореневою губкою насаджень належать до різних генеральних сукупностей. Виявлено, що в Лівобережному Лісостепу густота штучних соснових насаджень ІІІ–Х класів віку, створених на староорних землях і уражених кореневою губкою, в осередках усихання є достовірно меншою, ніж у міжосередковому просторі та еталонній частині міжосередкового простору (на 1–31 та 24–50 % відповідно). Середні висота й діаметр дерев, що ростуть в осередку всихання, є меншими на 1,6 та 1,8 % відповідно проти висоти й діаметра дерев, що ростуть у міжосередковому просторі, та на 5,2 та 3,7 % – проти відповідних показників еталонної частини міжосередкового простору. Визначено, що уражена частина соснового насадження – осередок всихання та міжосередковий простір – за станом є ослабленою та всихаючою: індекс санітарно стану становить від 2,0 до 3,7 та від 1,8 до 3,4 для осередку всихання та міжосередкового простору відповідно. Не уражена кореневою губкою частина насадження (еталонна частина міжосередкового простору) має ослаблений та сильно ослаблений санітарний стан через загущеність і відсутність рубок догляду. Запас ураженого кореневою губкою насадження залежить від поширення осередків усихання та від площі, яку займають власне осередки хвороби, міжосередковий простір та еталонна частина міжосередкового простору.

EVALUATION OF IMPACT OF FERTILIZATION ON SOIL SOLUTION CHEMISTRY IN DOMINATED FOREST SITE TYPES IN LATVIA

Enhanced forest growth may respond to the increasing demand for wood resources. Moreover, the forest is considered to be carbon storage, thus contributing to climate change mitigation. The forest soil fertilization, as well as forest drainage, thinning and regeneration may be an effective measure in increasing harvest rates. In the context of bio-economy, wood ash needs to be managed and can be utilized as an equivalent to potassium and phosphorus containing fertilizer. Ammonium nitrate can be used as fertilizer in forests on mineral soil since nitrogen is considered to be a tree growth limiting element in boreal forests. However, environmental aspects like leaching of the fertilizer should be taken into account. The aim of this research is to evaluate the impact of wood ash, ammonium nitrate and combined wood ash and nitrogen fertilizer impact on the chemical properties of soil water in dominated forest site types in Latvia. The trials were conducted in total in 16 forest stands. The fertilizers were spread in treatment plots, but the control plots were left untreated. The soil water samples were collected for two seasons. The pH, potassium, calcium, magnesium, phosphate and total nitrogen were determined in the soil water samples. Ammonium nitrate had an impact on the elevated concentration of total nitrogen in all experimental objects; although the significant differences between the control plot and treated plot were detected only in a part of experimental objects. The elevated concentrations of total nitrogen decreased after two months and remained above the control level. Interestingly, we observed a trend of both – increased and decreased concentrations of potassium, calcium, magnesium and phosphate. Nevertheless, only a part of the differences was statistically significant. The impact of wood ash on chemical properties of soil water was less pronounced in comparison to ammonium nitrate.

Pedunculate oak stands in the catchments of the river Vorskla’s tributaries

Abstract The aim of the study was to analyze the origin of oak stands within the catchments of the Vorskla’s tributaries and to describe their state. Covering 60,900 ha, pedunculate oak (Quercus robur L.) stands prevail and cover 51.1% of the total forest area of 119,200 ha in the catchment areas of the River Vorskla’s tributaries. The way oak stands are distributed in regards to trophotopes points at favourable conditions for their growth, as 81.7% of the area is a fresh fertile oak forest site type. Forest stands aged 41–80 years (39.8 % of the total area) and 81–120 years (50.4%) are prevailing. Natural oak stands cover almost 66.5% and planted ones grow at 33.5%. Distribution of oak stands in regards to the functional categories of forests shows a significant predominance of the protective forests. They cover 46.6% of the total area. The commercial forests cover 23.0%, the recreational ones make 18.8% and the forests with conservational, academic, historical and cultural purpose cover 11.6 %. Distribution patterns of oak forests in the catchments of the River Vorskla’s tributaries should be considered in the forest management in order to conserve their biodiversity and enhancing the performance of important environmental, protective, recreational and other functions. The article contains results of the study on the natural regeneration of Quercus robur and other wood species under the canopy of oak stands and on felling sites. The further research perspectives are a thorough study of the stand characteristics and the typological structure of forests in terms of certain wood species in the catchments of rivers all over Ukraine. It will help developing principles for the catchment and landscape zonation.

Diversity of old-drained forests in Estonia

Due to originating from various mire or paludified forests and consequently developing after drainage under different growth conditions, the drained forests are very heterogeneous and complex. In the official Estonian forest typology, the old-drained stands are divided into Myrtillus and Oxalis site types, but recently the validity of the autonomous Dryopteris (expansa) forest site type was again asserted. The aims of the current study were to (i) elucidate the main factors determining the structure and variation of the Estonian old-drained forests, (ii) elaborate the typology of these forests at the community level and, (iii) establish the indicator species of the established community types. 218 forest stands drained not less than 35–40 years ago were analysed. According to multivariate data analyses (cluster, ordination and variance analyses, multi-response permutation procedures, indicator species analyses) it appeared that the soil reaction, nutrients, and moisture content, assessed by the Ellenberg ecological indicator values for habitats are much more significant factors for plant growth and community structure than the thickness of soil/peat horizons. Nevertheless, the litter and peat horizons in soils of drained Dryopteris site type forests is significantly thinner than in Oxalis and Myrtillus site type stands. The Dryopteris site type forests can be divided into six, the Oxalis site type forests into three, and the Myrtillus site type forests into two types of communities. Each of the 11 established community types differ significantly (p < 0.05) from each other and have their own dominant and significant indicator species. When comparing the Estonian old-drained forests with analogous stands in neighbouring countries (Latvia, Finland, Sweden, northwestern Russia) we can find rather large similarities; the typological differences result mainly from the methodological approaches and geographical scope of countries.
 Key words: community types, drainage impact, Dryopteris forest site type, fern-rich forests, indicator species, Ellenberg indicator values, nutrition gradient.

Simulating the effect of forest fires, cuttings, and increased nitrogen deposition on dynamics of key forest ecosystem properties and processes in Russian North-West

The improved version of simulation model EFIMOD 2 was used for the estimation of forest ecosystem dynamics and analysis of basic linkages between stand structure, environment, and external factors, such as cuttings, forest fires, increased nitrogen deposition, which were considered both separately and in combination, in different boreal forest types of European Russia. According to the simulation results, increasing role of Norway spruce during the undisturbed development resulted in enrichment of forest floor and mineral soil by nitrogen by 5 and 10%, respectively. In contrast, fires promoted increase in Scots pine portion in stand composition, decrease in forest floor pool by 31%, in comparison with undisturbed development. Cuttings had the impact on stocks of soil organic matter through the decreased litter fall input that resulted from partial removal of tree biomass. The combined effect of fires and cuttings on ecosystem carbon pools was about 17% smaller than could be expected from the simple sum of the effects of both factors, which means that impact of one factor reduces (by affecting the same components of ecosystems) the possibility for negative influence of another one. The gradual increase in nitrogen deposition from 1.5 to 3.0 kg ha−1 year−1 for northern taiga and from 3.0 to 4.5 kg ha−1 year−1 for middle taiga by the end of 100-year simulation period had a positive influence on the carbon and nitrogen accumulation in trees’ biomass and soil organic matter (35% higher than in scenario without disturbances), thus partly overwhelming the impact from fires and cuttings. The important feature of the study is that the quantitative differences of stand and soil parameters between forest site types were revealed as well.

Characteristics of chosen biometric features of European ash (Fraxinus excelsior L.) due to the age of trees and the forest site type

The dieback of European ash contributes the disappearance of the species from the typical ash sites such as floodplain forests or alder-ash forests. The species occurs more often in moist broadleaved forests and fresh broadleaved forests. Therefore, the main objective of our study was to determine the influence of ash age and the forest site type on the chosen biometric features of dominant and codominant trees. We also aimed to compare the sizes of European ash growing in optimal forest site types with less fertile ones, where it does not occur as the main species. We collected the empirical material from 25 plots representing 4 forest site types: fresh broadleaved forest, moist broadleaved forest, floodplain forest, and alder-ash forest. The research plots were located in the Babki, Konstantynowo, and Łopuchówko Forest Districts, western Poland. The age of ash varied from 52 to 144 years. On each plot, we measured a tree height and a diameter at breast height of 15 dominant and codominant ash trees. Subsequently, we used measured features to calculate the volume of each tree. We carried out the analysis of covariance of diameter at breast height, height, and volume. The analysis showed the strong relationship of examined features with the age of the species and the forest site type. Furthermore, our results indicated the underestimation of the growth possibilities of European ash in fresh broadleaved forest and moist broadleaved forest. In these sites, ash achieved similar sizes in comparison to optimal forest site types, i.e. floodplain forest and alder-ash forest. This result cannot be omitted in forestry practice, especially in silviculture, which should aim to support the natural regeneration of European ash in differentiated site conditions.
 Keywords: European ash, forest site type, age of a tree, biometric features

Пірогенні зміни ґрунтів соснових насаджень

Унаслідок низових пожеж відбуваються зміни фізико-хімічних і біологічних властивостей ґрунтів. Досліджено пірогенні зміни властивостей ґрунтів у чистих соснових лісах, що ростуть у різних природних зонах України. У соснових насадженнях після низових пожеж у результаті як часткового, так і повного згорання підстилки утворюється попіл, що в подальшому впливає на хімізм верхнього шару ґрунту. Подібні особливості відзначали в різних природних зонах України. Надходження попелу в ґрунт призводило до зростання рН верхнього гумусового горизонту. Оскільки таке явище є одноразовим, то в подальшому після дощів значення рН водного витягу знижувалося до природнього рівня. Причиною пірогенних змін є високий уміст у попелі лужних металів. Інтенсивність змін реакції та вмісту лужних катіонів залежить від рівня згорання підстилки. Найбільш відчутними є зміни у разі повного згорання підстилки. Зазначені зміни мають поверхневий характер, тобто переважно притаманні лише верхньому шару ґрунту. На більшій глибині реакція не відрізняється від контролю.