<abstract><title style='display:none'>Abstract</title> Thirteen Nordic stand growth models have been validated by use of a test data set from long-term research plots in Norway. The evaluated data was from time-series of even-aged, pure stands of Norway spruce, Scots pine and birch (silver birch and downy birch). In selected models from Finland, Norway and Sweden measures of site productivity, mean tree size and various stand characteristics are represented. Different models display both strengths and weaknesses in their predicting ability. Several measures of precision and bias have been calculated and the models are ranked due to their performance. We observed site quality, stand density and average tree size as the three main components in the models. Basal area increment model for spruce from Sweden had the lowest standard deviation with 23%. The mean R2 between residuals and stand characteristics from this model was also low (1.3%), which indicates that independent variables are well included. For Scots pine and birch, Finnish volume increment models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7%, respectively. Several of the models from Sweden and Finland predicted the growth as well as stand models frequently in use in Norway. The results indicated that similar forest conditions and traditional even-aged forest management practice in the Nordic countries could be seen as a suitable basis for developing a joint family of growth models. By careful recalibration of existing models, a reasonable accuracy could be achieved and the prediction bias could be reduced.</abstract>

Comparison of selected Nordic stand growth models for Norway spruce, Scots pine and birch

<abstract><title style='display:none'>Abstract</title>Not much is known about the 17th-century Estonian and Livonian landscape architecture. Most of the information is based on the descriptions found in historical archival and literary sources and on some of the well-known engravings. According to these, a common idea of that era's landscape architecture is that it was humble in scale and design, and was similar to the practice of late-medieval times when there was no space or ambition to grow woody plants in small gardens of castles. But when diving into the Swedish manor plans dating back to the last decades of the 17th century, it can be noted that the layouts of manorial hearts are inherent to the spatial design of early baroque, which is characterized by a landscape that has strongly been redesigned and includes a decorative garden, kitchen garden and a park. This article focuses on the spatial composition of Estonian and Livonian manor parks of the second half of the 17th century and observes the role of trees and their use in these landscapes. This article is based on the results of a study about the planning of baroque manor hearts <italic>Understanding the Role of 18th Century Estonian Manor Ensembles in Contemporary Planning and Conservation</italic> (Eesti 18. sajandi mõisaansamblid 21. sajandi maastikuplaneerimises: avastamine, mõistmine, tõlgendamine) which was carried out by the author of this article. The map analysis results deal with the spatial structure of manor ensembles and the observations made during the analysis. The article examines the possible ways of using woody plants in 17th-century Estonian manors while looking at the manor ensemble as an architectonic of early baroque. Based on the research results it can be said that by the last decades of the 17th century the wealthiest manors had already built manor hearts with a modest but a clearly baroque style layout which is characterized by a regular and symmetrical ensemble core, a garden axially connected to the main building and avenues heading into the landscape. This type of approach enables to broaden the common conception of the era's garden and park architecture in the manor hearts of Estonia and Livonia. Based on what is highlighted in the article it can be said that the tradition and practice of garden art that has shaped the image of Estonian landscape had already been developed by the end of the 17th century.</abstract>

The use of woody plants in Estonian and Livonian manor ensembles during the second half of the 17th century

<abstract><title style='display:none'>Abstract</title>The relevance of the research topic is prompted by the need to improve the practical instruments of forest management and make them in line with the principles of sustainable development. The research is aimed at facilitating the implementation of environmental, social and economic functions of forest ecosystems in a long-term perspective. The study made use of the following methods: systemic structural analysis, clustering and comparative analysis to identify groups of administrative areas that correspond to certain strategic areas of sustainable forestry. The research is based on cybernetic modeling which helps determining the strategic zones of sustainable forestry. The stages of creating model forests were defined alongside formulating economic, organizational, social and environmental aspects of forest management. The methodology envisages grouping of administrative districts on the basis of a number of factors, including the percentage of forest land, social and economic indicators prompted. The methodology was implemented when analysing official data from several administrative districts in the Zhytomyr region. Several scenarios of sustainable forestry were detailed for each group of administrative districts. Three strategic options were pursued: 1) preserving the viability of forest ecosystems in Ukraine, 2) contributing to the welfare of Ukrainians, 3) ensuring economic development of the forestry sector. It follows from the research that the model forest is a powerful form of cost-effective business interaction in the process of sustainable development that shall bring into action the conservation of nature, provision of comfortable living conditions for territorial communities as well as the most capital-productive utilization of forest resources.</abstract>

Using model forests as a form of balanced forestry in Ukraine

<abstract><title style='display:none'>Abstract</title>The article explores conflicts related to forests and parks of Estonian towns from the Middle Ages to the 1940s. A brief overview is first given of the development of urban forestry in Estonia. There are also cases where the loss of urban forests and the related problems that arose could have led to conflicts, but for certain reasons they did not emerge. The main focus of the research is on Tallinn and its nearby island of Naissaare and, to a lesser extent, on the town of Haapsalu. The cases with the probability of conflict are described on the example of Tallinn, Tartu and Pärnu. It is apparent that conflicts or preconditions for their emergence were caused by various reasons, both at the state and town level where local authorities and ownership relations played their role. But the causes of the conflicts can also be traced to the wider clash between military and political causes, economic development and the general public.</abstract>

About the history of conflicts over urban forestry in Estonian towns

<abstract><title style='display:none'>Abstract</title>Tree-ring data is commonly used in forest science and dendrochronology. As the collected datasets represent restricted populations of theoretical infinite sample size, an interesting question deals with the sample selection that is carried out during the fieldwork and through the data analyses. This paper considers the latter issue, by statistically examining a recently completed Scots pine dataset of timberline tree-rings from Lapland (northern Finland). Following the detrending of individual ring-width series, the composition of the data was restricted using a pre-determined criteria of linear correlativity between the individual sample series and the master chronology (Rmaster). This procedure reduced both the number of sites and the sample size (i.e. the number of individual tree-ring series) and altered the tree-ring statistics of the remaining subset of the data in a systematic fashion. It was seen that the first-order autocorrelation, mean sensitivity and standard deviation all ascended with the uplifted Rmaster criterion. Conspicuously, such filtering also reduced the correlation between the resulting tree-ring chronology and climate parameter. The results indicated that the screening of the data will alter the chronology statistics in a way that may be artificially generated, irrelative to the predetermined sample selection criteria. We remain to assume that the most fundamental selection of data is attained through the cross-dating process.</abstract>

Finnish Forest Research Institute, P.O. Box 16, 96301 Rovaniemi, Finland

Finnish Forest Research Institute, P.O. Box 18, 01301 Vantaa, Finland

Timberline tree-ring statistics examined through chronology stripping

One hundred years of academic forestry education in Estonian

<abstract>
<title style='display:none'>Abstract</title>
In a managed forest landscape, the high degree of human intervention has caused significant shifts in natural processes, and preservation of remaining natural ecosystem features is crucial to safeguard ecosystem functioning and support ecosystem services. While drainage ditches, subject to regular maintenance, are anthropogenically created and maintained infrastructure elements, they may still support diverse environmental conditions and provide habitats for a variety of plant species, including flowering plants important for pollinators. We assessed vegetation composition changes on recently reconstructed and unmanaged forest ditches and ditch edges in a commercial forest in Central Latvia in two surveys (one and five years after the ditch reconstruction). We used generalized linear mixed-effects models to analyze the impact of environmental variables on species richness and detrended correspondence analysis to analyze plant species composition. We found higher total plant species richness and insect-pollinated plant species richness along recently reconstructed ditches. The differences were mainly explained by better light availability beside reconstructed ditches. Anthropogenically created and managed ecosystems may support biodiversity and directly and indirectly contribute to the provision of different ecosystem services, including pollination.
</abstract>

Vegetation response to forest ditch reconstruction: Promoting a potential habitat for insect-pollinated plant species?

<abstract>
<title style='display:none'>Abstract</title>
The reduction of greenhouse gas (GHG) emissions demands a significant increase in the use of wood as a renewable energy source. However, environmental restrictions determine limits on the further growth of harvesting volume. Therefore, a viable solution to enhance the share of energy wood in Estonia’s energy balance involves focusing on less exploited assortments of raw material and implementing precise logistics planning. In recent years, mild winters have posed challenges to the extraction of residues and local transport of wood fuels, taking place on soft and unfrozen soils. In such conditions, ensuring a reliable supply of wood fuels becomes rather complicated. When piles of logging residues on unfrozen soils are inaccessible, there is a need to process older piles. The quality of wood chips from such piles is lower compared to the norm. To investigate the impact of extra long-term storage of residues in piles, a study was conducted at the Järvselja Training and Experimental Forest Centre. In 2010, sample piles were created in birch and spruce final felling areas. Over an eight-year period, samples were regularly taken from the piles to analyse the properties of woody biomass during storage. The study results indicate that the quality of fuel from covered piles changes slowly during the first two years of storage. Subsequently, the degradation speed equalizes in both uncovered and covered piles. Despite extensive degradation and loss of dry matter during long-term storage (approximately 29% for Norway spruce and 55% for silver birch after eight years), the quality of dry fuels still meets standard requirements and remains acceptable for boiler houses.
</abstract>

The impact of extra long-term storage of logging residues on fuel quality in Estonian conditions – a case study

<abstract>
<title style='display:none'>Abstract</title>
There are no systematic approaches available in current specialist literature when it comes to the optimization of the process of drying out hardwood species of wood, such as birch, aspen, or black alder, all of which find industrial uses in Estonia. In order to investigate the drying of these three hardwood species, this paper has made use of an experimental and theoretical drying optimization methodology which was developed previously for pine sapwood within the framework of the EIC Grant No. 16200 project. The same methodology was used to determine the critical diffusion coefficient and corresponding critical relative humidity levels (RH) in relation to the surrounding air, with those levels being important from the point of view of drying optimization, and calculating those levels separately for each species of hardwood. For alder it was found that the critical diffusion coefficient is Dcr = 36.57 * (10−4 mm2 s−1), while for aspen the figure was Dcr = 30.71 * (10−4 mm2 s−1), and for birch it was Dcr = 16.35 * (10−4 mm2 s−1). It was found that the time dependencies for the total deformation of different tree species tend to differ considerably, although the same drying regime was used for all of those tree species which were incorporated into the experiments.
</abstract>

An experimental determination of the critical diffusion coefficient and critical relative humidity (RH) of drying air when optimizing the drying of three hardwood species (birch, aspen, and black alder)

<abstract>
<title style='display:none'>Abstract</title>
Understanding how forest ecosystems respond to environmental factors, particularly in the context of global climate change, is essential for devising effective mitigation strategies. This study focuses on quantifying the interaction between forest ecosystems and atmospheric gases. To achieve our objectives, we are using the eddy covariance (EC) flux method to measure air turbulence and gas concentrations above the forest canopy at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) in southern Estonia. We apply a flux footprint (FFP) model to describe the spatial extent and position of the surface area contributing to the turbulent flux measurements. The FFP analysis provides valuable insights into the long-term changes in SMEAR Estonia, the FFP and its relationship with forest management and land use changes. Our findings reveal that the FFP area varies from year to year due to changes in wind speed and direction, affecting the contribution of different land cover elements to the overall FFP. The average changes in the FFP area at a height of 30 meters were approximately 4.9%, while those at a height of 70 meters were only 1.6%. Moreover, human activities, such as thinning and clear-cutting, influence the growing stock and increment of forest stands.
</abstract>

Development of a footprint description tool utilizing SMEAR Estonia eddy-covariance data and footprint modelling in combination with remote sensed forest species and land cover data

<abstract>
<title style='display:none'>Abstract</title>
The aim of this paper was to provide an overview of the productivity of the stump lifting device Pallari KH-160, the distribution of working time, and to assess the dependence of the time and productivity of lifting operations on stump diameter in four different sample areas. Viru and Orguse sample areas were located in the <italic>Hepatica</italic> site type, Elva sample area in the <italic>Oxalis</italic> site type, and Rõuge test area in the <italic>Myrtillus</italic> site type. Viru sample area had smaller stumps compared to the others and had more stumps affected by decay. The highest productivity in terms of dry mass or volume was observed in stump lifting in Rõuge sample area, where 9.8 t of stumps were lifted per hour based on dry mass. The productivity of Viru and Orguse sample areas was lower, but these sample areas are located in the <italic>Hepatica</italic> site type, characterized by limestone substrates and leached soils. In contrast, Elva and Rõuge test areas are in the <italic>Oxalis</italic> and <italic>Myrtillus</italic> site types, respectively, with soils that are predominantly sandy. As the diameter of the stumps increased, the time required per stump increased, but the lifting speed per unit mass also increased. In other words, the productivity of lifting in stands with larger stumps is higher than in stands with smaller stumps. For example, the average productivity of lifting 10 cm diameter stumps is 0.8 t/h, for 20 cm stumps it is 2.2 t/h, and for 60 cm stumps it is 11.8 t/h.
</abstract>

Hariliku kuuse (<italic>Picea abies</italic> (L.) H. Karst.) kändude juurimise tootlikkus juurimisagregaadiga Pallari KH-160 neljal Eesti katsealal

<abstract>
<title style='display:none'>Abstract</title>
<italic>Phellodendron chinense</italic> is an extraordinary medicinal plant, and its stem bark is a famous traditional Chinese medicine in China, containing a number of phytochemicals with biological and pharmacological functions. Studies have shown that the medicinal ingredients in <italic>P. chinense</italic> from various regions are different, as soil types might be important factors affecting the growth and quality of <italic>P. chinense</italic>. In this study, the effects of acidic purple soil, alkaline purple soil, yellow soil and red soil on the growth, nutrient element accumulation and partitioning in <italic>P. chinense</italic> seedlings were studied. Our results showed that the biomass of leaves and stems in acidic purple soil was significantly higher than in other soils, and the root biomass was significantly lower than that in yellow soil. C, N, P and Ca contents cultured in acidic purple soil were the highest compared to other soils, and K and Mg content were the highest in yellow soil and red soil, respectively. The distribution of carbon between different organs can reflect environmental stress. N has become a limiting factor for the growth and development of <italic>P. chinense</italic> seedlings. C:N and C:P ratios in the leaves were significantly lower than those in the stem and roots. Among four soil types, the highest N:P ratio was 1.65 in <italic>P. chinense</italic> seedlings. These results suggest that four soil types may significantly affect the accumulation and distribution of biomass and nutrient elements in <italic>P. chinense</italic> seedlings. The characteristic patterns in different organs have different responses. Acidic purple soil is more suitable for the growth of <italic>P. chinense</italic>. These findings will help to understand the distribution characteristics and requirements of nutrient elements in <italic>P. chinense</italic> seedlings, and further provide a theoretical basis and reference for site selection and cultivation strategy.
</abstract>

Effects of four soil types on growth responses and nutrient stoichiometry in <italic>Phellodendron chinense</italic> seedlings

<abstract xml:lang="en"><title style='display:none'>Recent invasion of foliage fungi of pines (<italic>Pinus</italic> spp.) to the Northern Baltics</title>In the wake of severe climatic extremes during recent years, several new invasive foliage fungi of pines have been reported in Estonia. In this paper the peculiarities of the fast dissemination process, particularly from south to north of two quarantined species, <italic>Mycosphaerella pini</italic> and <italic>M. dearnessii</italic>, but also of <italic>Diplodia pinea</italic> and <italic>Cyclaneusma minus</italic> on different host species are described. These species were known as destructive pathogens in several countries and continents. By today, the range of <italic>M. pini</italic> has already reached northern Finland. In its dissemination process we could follow, with the half-year steps, colonization of Estonia from south to north. Some micromorphological features of these alien species were investigated. Hypothetical risk for pine forests was shortly introduced.</abstract>

Recent invasion of foliage fungi of pines (<italic>Pinus</italic> spp.) to the Northern Baltics

<abstract><title style='display:none'>Abstract</title><italic>Eucalyptus</italic> is a plant frequently present and cultivated in arid regions because of its high adaptation to drought. Furthermore, it is known by its numerous species which represent<italic>s</italic> a great opportunity to choose several tolerant species with variable uses. Therefore, the choice of species, hybrids or genotypes resistant to aridity becomes a necessity before any plantation in regions and countries characterized by semi-arid, arid and Saharan climates. Our review shows an important effect of drought on anatomical, physiological and biochemical parameters of <italic>Eucalyptus</italic> spp. Indeed, water stress acts directly on growth, yield and response to pests. However, the response to drought varies significantly among species, genotypes, hybrids and clones. This result represents a field for the selection of eucalypts tolerant and adapted to water deficit or climate change.</abstract>

An overview of adaptative responses to drought stress in <italic>Eucalyptus</italic> spp.

<abstract><title style='display:none'>Abstract</title>Establishment of the SMEAR Estonia at a hemiboreal mixed deciduous broad-leaved-evergreen needle-leaved forest at Järvselja, South-Eastern Estonia, has strongly enhanced the possibilities for national and international cooperation in the fields of forest ecosystem – atmosphere research and impacts of climatic changes on forest ecosystems, atmospheric trace gases, aerosols and air ions. The station provides a multitude of comprehensive continuously measured data covering key climatic and atmospheric characteristics (state and dynamics of solar radiation, trace gases, aerosols and air ions, meteorological parameters) and forest ecosystem traits (net primary productivity, individual tree growth, gas-exchange characteristics, soil variables). The station follows a multidisciplinary and multiscale approach covering processes in spatial dimensions ranging from nanometres to several hundred square kilometres, being thus able to significantly contribute to worldwide measurement networks and the SMEAR network. Here we present an overview of the station, its data produced and we envision future developments towards sustainable research and development of the large-scale scientific infrastructure SMEAR Estonia.</abstract>

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 51014 Tartu, Estonia

Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia

Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia

Institute of Physics, University of Tartu, 18 Ülikooli Street, 50090 Tartu, Estonia

Department of Forest Sciences, P.O. Box 64, FI-00014 University of Helsinki, Finland

Division of Atmospheric Sciences, Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland

SMEAR Estonia: Perspectives of a large-scale forest ecosystem – atmosphere research infrastructure

<abstract><title style='display:none'>Abstract</title> Forest research has long traditions in Estonia that can be traced back to the 19th century. Data from long-term forest experiments are available since 1921. The first studies mainly focused on silvicultural treatments and application of such data for understanding and modeling ecological processes was limited. The Department of Forest Management of the Estonian University of Life Sciences started to develop the Estonian Network of Forest Research Plots (ENFRP) in 1995. Since then, plots have been continuously re-measured with 5-year interval. Approximately 100-150 permanent sample plots were measured annually. In 2014, the long-term research network consisted of 729 permanent sample plots, of which 699 have been re-measured at least once, 667 plots - twice and 367 plots - three times. The total number of trees recorded in the network database amounts to 130,479. The plots are systematically distributed throughout the country. Detailed dendrometric measurements including tree spatial distribution are part of the survey protocol. Initially the network was set up to produce suitable data for development of individual tree growth models for Estonia. The significance of the network for the Estonian forest research is continuously increasing and nowadays ENFRP is recognized as an important national research infrastructure.</abstract>

Monitoring and modeling of forest ecosystems: the Estonian Network of Forest Research Plots / Metsaökosüsteemide seire ja modelleerimine metsa kasvukäigu püsiproovitükkide võrgustiku abil

<abstract><title style='display:none'>Abstract</title>Wildfire is regarded as important environmental factor determining the vegetation of the Earth. We analyzed 11 plots at different types of forest affected by fire at the southern boundary of the taiga zone. These differ in structure of the forest stand and herb-shrub layer. Investigated factors included edaphic (moisture, pH, nitrogen) and climatic (light, temperature, continentality) characteristics. Also, projective cover of <italic>Epilobium angustifolium</italic> L. and undergrowth of secondary growth trees (including forest stand survived after fire influence) were studied. Multivariate data analysis revealed that the rate and character of the vegetation recovery was depended on the ratio of environmental factors and on the species composition of herb-shrub layer. No significant differences were found in Ellenberg’s indicator values between different years of study. All tested forest habitats were distinguished into three main groups: Group I includes broadleaf forests with the forest stand survived after fire influence, Group II includes spruce and birch forests deprived the forest stand due to fire impact, Group III includes more or less dry pine-dominated forests with the forest stand gradually died after fire influence. Two marshy plots have prerequisites to their allocation to a separate group close to the oligotrophic bog forests.</abstract>

Mordovia State Nature Reserve, 431230, Pushta, Temnikov district, Republic of Mordovia,

Department of Botany, Physiology and Ecology of Plants, Mordovia State University, 430005, Bolshevistskaya Street, 68, Saransk, Republic of Mordovia,

National Park “Smolny”, 431660, Topoley Street, 11, Smolny, Ichalki district, Republic of Mordovia,

Vegetation recovery in fire-damaged forests: a case study at the southern boundary of the taiga zone

<abstract><title style='display:none'>Abstract</title>Field measurements from 450 sample plots, airborne lidar data and spectral images from Aegviidu, Estonia, 15 by 15 km test site were used to analyse options to estimate main forest inventory variables using remote sensing data. Up to 7 m random error in location of 15 m radius sample plots within homogeneous stands causes usually about 0.5 m standard deviation in lidar pulse return height distribution percentiles. Forest mean height can be predicted with linear relationship from 80th percentile of lidar pulse return height distribution. Upper percentiles of pulse return height distribution are not significantly affected by omitting returns from ground and forest understorey vegetation. Total stem volume in forest can be predicted by using 80th percentile, 25th percentile and canopy cover as model arguments with less than 70 m3 ha-1 standard error. Best species specific stem volume models had 10 m3 ha-1 smaller standard error.</abstract>

Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia;

Tartu Observatory, 61602, Tõravere, Tartumaa, Estonia;

OÜ Metsabüroo, Kadaka tee 86a, 12618, Tallinn, Estonia

Tartu Observatory, 61602, Tõravere, Tartumaa, Estonia

Lennukilidari ja spektraalse kaugseireandmestiku kasutamine metsa peamiste takseertunnuste hindamiseks Aegviidu katsealal / Estimation of main forest inventory variables from spectral and airborne lidar data in Aegviidu test site, Estonia

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