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Compositional dynamics of natural forests in the Bialwieza National Park, northeastern Poland
Abstract
This paper presents results of a long‐term study on natural forest dynamics in the Białowieza National Park (BNP), northeastern Poland. Five permanent sample areas were used, each consisting of a transect of varying width (40 ‐ 60 m) and length (200 ‐ 1380 m). The total sample area is 14.9 ha. The study covers the period 1936–1992. During this period measurements were made on five occasions at approximately 10‐yr intervals. On each measurement date all trees with DBH > 5 cm were identified and their spatial location, diameter, crown condition and position in the canopy determined.
During the study period the stands underwent noticeable changes, mainly in terms of tree species composition. The major change was a quantitative increase of the late‐successional species: Tilia cordata and Carpinus betulus , also to a lesser degree Fraxinus excelsior and, in the last period, of the early successional Alnus glutinosa . Declining species included both early‐ and late‐succession species. Among the latter group, Picea abies ranked first. This species lost much of its importance during the last few decades. P. abies was followed by Pinus sylvestris which is an important component of the climax vegetation under the conditions prevailing in Bialowieza, at least on more oligotrophic sites. Still, this species has not been able to regenerate during the whole study period. Some other late‐succession species, Acer platanoides and Quercus robur , were also amongst the declining species. Although the basal area of Q. robur increased, its population was getting older and the process of natural regeneration was markedly impeded.
All typical pioneer, short‐lived species: Betula pendula and B. pubescens, Salix caprea and Populus tremula also decreased, which was probably caused by a lack of major disturbances during the study period.
In general, the results obtained for the semi‐natural conditions of Bialowieza during the 56‐yr observation period suggest a rather high compositional instability of the forest stands there. A more precise identification of the role of particular factors in the observed stand dynamics is difficult because of the paucity of appropriate historical and environmental data which refer directly to the study plots; moreover, the data are generally incompatible and of different resolution.
... The most visible processes of CB succession were observed in the thermophilic oak forests in BF after antropopresure. Hornbeam regenerates quickly in the understorey, where it shades the forest floor and prevents the growth of other tree species, and eventually takes over the canopy, displacing other heliophilous and even sensitive shade-tolerant species 7,87 . Our research shows that the succession of a particular species-even a native one-significantly affects the soil, the complexity of biochemical processes at the plant-soil interface requires that we predict the future fate of BF with some distance. ...
Carpinus betulus (CB) is becoming increasingly important in the forests of Central Europe and is significantly increasing its proportion in various habitat types. We have analysed how the increase in CB affects soil properties. The study was conducted in the Białowieża Forest (BF). We monitored the changes in CB cover between 1962 and 2013 on 56 permanent plots and collected samples of the litter sub-horizons and the content of the underlying A horizons for laboratory analyses in 2014. During the study period, there was a significant increase in CB cover in the second tree layer by an average of 17.4 % (±1.8) and in the shrub layer by 3.8 % (±1.0), as well as an increase in species diversity from 41 % in the past to 59 % currently. The C/N ratio of the Oi sub-horizon was 32.0 (±0.9), and NH4+ compounds predominated over NO3-, with all nitrogen forms most closely associated with the C/N ratio. In the Oea sub-horizon, the C/N ratio was 23.4 (±0.4), and the sum of mineralised nitrogen reached 8%, with a clear predominance of NO3-. The characteristic most strongly associated with the increase in CB coverage was the NO3- content in the Oea sub-horizon. The MID analysis confirmed that the change in CB cover was not only significant, but also ecologically important. We suggest that there is a feedback loop in which the generally observed climate changes lead to trees occupying new habitats that supply the forest floor with high quality litter, which in turn affects the soil and promotes the persistence of changes in the species composition of the forest.
... Thus, the diameter of the trunks, height of the tree, and chemical composition of the wood are some of the variables that suffer temporary variations and are used to describe forest trends. Similarly, the distribution of the diametric classes allows us to understand the dynamics of forests, their relationship with environmental factors, and their response to management (Caritat, Molinas & Oliva, 1991;Bernadzki et al., 1998;Solomon and Gove, 1999). ...
Mangroves are swampy forests located along tropical and subtropical coasts around the world. Their distribution is restricted to coastal areas where periodic flooding occurs. In addition, the species that dominate in these environments have different adaptations for occupying unstable substrates, tolerating salinity, exchanging gases
in anoxic substrates, and reproducing through propagules. These mangroves constitute an ecosystem that presents environmental variations, which is why there is low diversity of tree species. Despite the dominance of a single species (R. mangle), the accompanying species significantly increase the diversity of the ecosystem, showing that it is a complex and resilient ecosystem.
Future research needs should focus on the physical and chemical characteristics of the soil: the horizontal zoning of the species and how the physical-chemical factors determine their presence. At the same time, it is necessary to understand the regeneration processes and the role of exotic plants in the ecosystem.
... However, its natural (primeval) gene pool has been significantly modified as a result of extensive forestry, cultivation and selection activities, as well as due to seed transfers (Puumalainen et al., 2003).The Scots pine is also the most important forest-forming species in the Białowieża Forest, covering 27% of the forest area (Sokołowski, 2004). Long-term studies (since 1936) on the development dynamics of the natural tree stands in Białowieża National Park (which is part of the Białowieża Forest) under strict protection conditions have indicated a decrease in pine numbers and a regression of the forest's natural renewal in the 20th century (Bernadzki et al., 1998;Samojlik, 2006). As a light-demanding species, the pine requires open, sunny stands for its restoration, and such stands are quite rare in the forest. ...
The last fragments of primeval forests in the European lowlands have survived in the Białowieża Forest (BF). A characteristic feature of its forest stands is a complex and multi-age structure. From a genetic perspective, old trees represent a genetic pool that is a product of the selection forces acting over centuries. Therefore, it is extremely important to make a genetic inventory of such old trees and preserve their genetic resources for future generations. The aims of this study were: 1) genotyping the oldest trees of Pinus sylvestris in the Sitki Reserve of the Białowieża Forest in Poland; and 2) characterisation of the genetic structure of this old Scots pine tree stand. In total, 98 old trees aged above 100 years were analysed using eight nuclear microsatellite markers. The first study on the genotyping of the oldest Scots pine trees in the BF, indicated that each of the trees has a unique genotype, so it can be unambiguously identified by a genetic profile. Overall, 85% of trees showed an individual heterozygosity of 0.5 or higher. We demonstrated, that eight polymorphic microsatellite loci of the nuclear genome are sufficient to create an individual genetic profile of each tree. Our results will provide necessary background information for the conservation of native genetic resources of Pinus sylvestris.
Effective conservation of biodiversity requires a good understanding of ecosystem dynamics in response to natural and anthropogenic influences. Long-term studies (LTS) conducted over multiple decades provide essential insights into ecological processes and interactions over time, which can inform conservation strategies, but they are anchored within their wider society and geopolitics. The context of any LTS is therefore vulnerable to temporal instability, including disruptions and challenges but also scientific opportunities. The resilience and adaptability of LTS in the face of political, social or environmental change is key to their continuity and relevance for science and society. Poland's iconic Białowieża Forest hosts unique remnants of European old-growth forest, and also diverse LTS lasting up to nine decades, revealing a dynamic ecosystem. The Białowieża Forest is a hub of international science, providing an essential reference for ecosystem functioning and evolutionary processes, and a key benchmark for wider perceptions of 'natural forest', which is increasingly relevant to ecological restoration elsewhere. Nevertheless, the Białowieża LTS have persisted against a backdrop of profound sociopolitical and geopolitical change, which has challenged their scope and viability. The Białowieża experience has a wider resonance for LTS in other regions, because change can affect science anywhere, even in situations that currently appear stable. We describe how Białowieża's LTS have maintained continuity and relevance for our understanding of forest ecosystems by embedding core expertise among diverse institutions, building collaborative teams around visionary leaders and dispersing risks of financial, political and security vulnerabilities. However, issues remain around centralised data archiving and availability. These perspectives provide general lessons for supporting LTS in a changeable world.
Silver fir (Abies alba Mill.) is a typical mountain tree species, but it can also grow in lowlands below 300 m a.s.l., where it must coexist with a variety of competitors. Much less were studied in the northeastern part of its natural range, where annual precipitation varies between 500 and 600 mm, distinctly less than in the mountains. The general objective of this study was to investigate the regeneration process of silver fir in mixed lowland forests in regions with water shortage. The evaluation of spatial relationships between old, dominant and newly established trees was used to clarify the mechanisms of tree species coexistence. The study was conducted in managed and protected stands in Janów Forests in the southeastern part of Poland. We selected mature forest stands (oldest trees older than 100 years) representing three types of mixed stands in nature reserves, as well as in comparable managed forests. Data was collected on 500 m 2 sample plots established randomly in each stand category (20 sample plots × 6 stands). Silver fir as the target tree showed statistically significant segregation from other species in 15 cases. Small silver fir trees were associated with large pines in two forest types and segregated form large firs in one. The spatial relationships between fir and black alder were negative. Black alder was the second species with the most statistically significant spatial relationships with other tree species (11 cases). Alders separated from large pines and large firs and from medium and small silver firs. Strong segregation of medium-sized hornbeam from the small class of silver fir was observed. Our study showed that silver fir natural regeneration and colonization of new areas at the northeastern limit of its range are limited by low seed rain density, interactions with other competing species, and local site conditions. Areas with moderately high water table are potentially suitable for fir regeneration, but black alder has a competitive advantage in wetter parts of forest stand. The major advantage of such sites is the absence of beech populations, which are an important competitor to fir in the central European mountains, but a likely equally important limitation would be the presence of hornbeam populations. Our results suggest that less intensive cuttings at carefully selected places are more conducive to fir regeneration than more intensive salvage cuttings.
Agroforestry systems (AFS) show large potential to tackle global problems on various fronts, for example by reducing biodiversity loss, whilst also increasing sequestration of carbon as well as efficiency of N-cycling. To cope with the growing demand for AFS in Austria, the need arises to establish agroforestry research stations (AFRS). This study thus proposes preliminary recommendations for an AFRS design at the experimental station Groß Enzersdorf (VWG) using a systemic approach thereby accounting for AFS design often being multi-faceted. This is done through the novel approach of applying the tree scoring method, common in tropical agroforestry, in a temperate context. This may help to objectify tree selection for AFS, which to this date is rarely ensured. The experimental design of three AFRS case studies is further reviewed in order to analyse their applicability to an AFRS at the VWG. With a strong focus on the methodology of the tree ranking method, this study highlights the methods potential for improvement by pointing out major research limitations, such as the strong reliance on extensive tree attribute data, which is currently not available. Rather than considering all potential tree species, only a selection of twelve species was evaluated using the scoring method, thus the results should be regarded as preliminary. This study proposes the use of species that performed well in the scoring method, to be integrated into on-farm field trials, thus testing already existing concepts of AFS in their potential to provide important functions, such as reducing wind erosion, which may be highly relevant in the Marchfeld region. Overall, this study highly recommends the establishment of an AFR at the VWG, which could play a leading role in sustainable food production in Austria.
Keywords:
Agroforestry, Agroforestry Design, Agroforestry Research, Tree Selection, Tree prioritization, Experimental station Groß-Enzersdorf
Forests hold a significant proportion of global biodiversity and terrestrial carbon stocks and are at the forefront of human-induced global change. The dynamics and distribution of forest vegetation determines the habitat for other organisms, and regulates the delivery of ecosystem services, including carbon storage. Presenting recent research across temperate and tropical ecosystems, this volume synthesises the numerous ways that forests are responding to global change and includes perspectives on: • the role of forests in the global carbon and energy budgets • historical patterns of forest change and diversification • contemporary mechanisms of community assembly and implications of underlying drivers of global change • the ways in which forests supply ecosystem services that support human lives. The chapters represent case studies drawn from the authors' expertise, highlighting exciting new research and providing information that will be valuable to academics, students, researchers and practitioners with an interest in this field.
Forests hold a significant proportion of global biodiversity and terrestrial carbon stocks and are at the forefront of human-induced global change. The dynamics and distribution of forest vegetation determines the habitat for other organisms, and regulates the delivery of ecosystem services, including carbon storage. Presenting recent research across temperate and tropical ecosystems, this volume synthesises the numerous ways that forests are responding to global change and includes perspectives on: • the role of forests in the global carbon and energy budgets • historical patterns of forest change and diversification • contemporary mechanisms of community assembly and implications of underlying drivers of global change • the ways in which forests supply ecosystem services that support human lives. The chapters represent case studies drawn from the authors' expertise, highlighting exciting new research and providing information that will be valuable to academics, students, researchers and practitioners with an interest in this field.
Forests hold a significant proportion of global biodiversity and terrestrial carbon stocks and are at the forefront of human-induced global change. The dynamics and distribution of forest vegetation determines the habitat for other organisms, and regulates the delivery of ecosystem services, including carbon storage. Presenting recent research across temperate and tropical ecosystems, this volume synthesises the numerous ways that forests are responding to global change and includes perspectives on: • the role of forests in the global carbon and energy budgets • historical patterns of forest change and diversification • contemporary mechanisms of community assembly and implications of underlying drivers of global change • the ways in which forests supply ecosystem services that support human lives. The chapters represent case studies drawn from the authors' expertise, highlighting exciting new research and providing information that will be valuable to academics, students, researchers and practitioners with an interest in this field.
For 25 years research in natural forest reserves has been pursued in Western Germany. A survey is given of problems and perspectives of this branch of research on the basis of general deductions as well as a retrospective evaluation in Lower Saxony from 1972-1992. On the one hand research in natural forest reserves can bear valuable knowledge because it is based on time series of natural processes. On the other hand problems concerning target-orientation and continuity of methods are stated. To solve these problems it is suggested to develop and lay down a modell-orientated research-concept. The retrospective shows that the network of natural forest reserves has undergone major changes due to dissolution of old and establishment of new reserves. Dissolution often has to be assigned to the fact that natural forest reserves are a matter of conflict. Nowadays, strong emphasis is layed firstly on selecting natural forest reserves strictly according to criteria which help to avoid conflicts and secondly on a care- and control-system in established reserves. From the first to the third inventory period research methods for woody plants have changed significantly. While some of the changes are evaluated positively, others have to be criticized because they have led to the partial disconnection of time series. The state of research is charaterized by a multitude of scientific publications which are insufficiently related with each other. Furthermore a deficiency of interpretation of data and of methodological studies has to be stated. Prospects of research in natural forest reserves could be opened up, if the relative position amongst other research branches is more strongely considered, the connection of data in space and time is intensified and some special methodological problems are solved. It is suggested that a research-concept should build the framework for these future tasks. This concept is presented for the research about woody plants.
The population dynamics of Betula pubescens and Picea abies in a boreal forest near Kvikkjokk, northern Sweden, are governed by a process of storm gap regeneration similar to the gap
regeneration described for boreo-nemoral forests. Cumulative age distribution curves, interpreted as static survivorship curves,
lead to a simple theory of differential survival based on properties of the species, i.e. shade tolerance and relative growth
rate. The theory is sustained by diameter and height distributions and by the spatial distributions of logs and of trees in
different life-phases. Species of the field and ground layers respond differentially to gap formation and the ensuing successional
stages. Browsing by moose (Alces alces) may prevent tree species, mainly Sorbus aucuparia, Betula pubescens and Pinus sylvestris, from developing into a tree layer. The regeneration ability for tree species growing in a stand at 460 m a.s.l. is limited
compared with the regeneration at 330 m a.s.l., and typical storm gap formation involving more than one tree seems to occur
rarely if at all, while overthrown trees with exposed rootplates are uncommon. Spruce at 460 m a.s.l. shows also a lower growth
rate and a lower height/diameter ratio compared to the lower situated stands.
To learn about the interactions between individual trees and between trees and other forest organisms, long-term monitoring of spontaneous forest development is necessary. A complete monitoring system has been developed including a computer package for analysis of long-term forest dynamics observations. A method of nested plot data collection on forest architecture and plant species composition has been worked out for monitoring purposes. The spatial and temporal relations between data are numerically expressed. Therefore a three-dimensional single-tree architectural model has been worked out to describe asymmetric tree shapes with a minimum of measured data points. Time series of forest development at different sites are built up on the basis of a digital descriptive model of the complex reality of forest structure and species composition.To guarantee continuity in data storage and data query a commercially available database and a geographical information system were used in the design of the information system. A visual interpretation of data is enabled by graphical system outputs such as profiles and ground plans of tree crown projections, providing substitutes for traditional profile drawings and maps. Application programs were developed to solve specific problems, as a step towards predictive models. In an application program, for integration with remote sensing studies, an aerial view of the forest canopy is simulated on the basis of measured plot data. This view provides a ground-truth reference for the training and interpretation of remote sensing images. To explain the growth of individual trees and the distribution patterns of herbs and tree regeneration on the forest floor, another application was developed, simulating the penetration of direct and of diffuse light. For the reconstruction of forest growth with tree ring data, a technique of animation was elaborated facilitating a visual interpretation of the forest development. The system is applied to demonstrate forest development in some European forest reserves using forest architectural descriptions and vegetation releves, tree ring data and historical sources.
The 35-ha stand of mixed native broadleaves at Lady Park Wood, Forest of Dean, Gloucestershire, was designated as an unmanaged nature reserve in 1944. It had for centuries been treated as coppice or coppice-with-standards to survive unaffected by significant planting. Most of the stand has been largely untouched since 1902, and is dominated by trees dating from 1800-1900; this old growth stand is the subject of this paper. Until the 1970s the stand remained undisturbed, increasing in basal area and decreasing in density. Beech Fagus sylvatica steadily increased in dominance by faster growth, lower mortality or both than other trees. The shrub stratum was almost eliminated. Only on the precipitous lower slopes, where beech was uncommon and the stand was perpetually disturbed by trees falling from insecure footholds, were other species generally dominant and the shrub layer vigorous. In the early 1970s disease struck the elms Ulmus spp and thus further opened the woodland on the lower slopes. In the openings created by this and earlier falls, regeneration has been patchy. The severe summer drought of 1976 killed many mature beeches and greatly reduced the vigour of the rest. As a result, the canopy of the stand on the dry upper slope has disintegrated in patches and openings have been increased by windthrow. This process was still continuing in 1983, by which date regeneration had not started. The succession towards beech dominance has been abruptly halted, and the most likely beneficiaries are ash Fraxinus excelsior and lime Tilia spp. -from Authors
To most early ecologists, the ‘natural’ ecosystem was the community that would be reached after a long period without large-scale disturbance (fire, windstrom, etc.). More recently, it has been realized that in most areas some type of large-scale disturbance is indigenous, and must be included in any realistic definition of ‘naturalness’. In some areas an equilibrium may exist in which patchy disturbance is balanced by regrowth, but in others equilibrium may be impossible because (1) individual disturbances are too large or infrequent; (2) ephemeral events have long-lasting disruptive effects; and/or (3) climate changes interrupt any movement toward equilibrium that does occur. Examples of non-equilibrium ecosystems include the African savannas, the Big Woods of Minnesota, the lodgepole pine forests of Yellowstone National Park, and possibly the old-growth Douglas-fir forests of the Pacific Northwest.Where an equilibrium does not exist, defining the ‘natural’ vegetation becomes much more challenging, because the vegetation in any given area would not be stable over long periods of time even without man's influence. In many areas it may be unrealistic to try to define the natural vegetation for a site; one must recognize that there are often several communities that could be the ‘natural’ vegetation for any given site at any given time.
Range limits and broad-scale geographic variations in the productivity of boreal and northern deciduous tree species in Europe are simulated with a bioclimatic model (STASH). STASH is based on a small number of distinct mechanisms by which climate is thought to affect the survival, regeneration and growth of trees. Survival is limited by summer warmth requirements and winter cold tolerance; regeneration, additionally by winter chilling requirements; and growth rate by net assimilation, which in turn is related to photosynthetically active radiation, growing-season length, temperature (relative to species-specific optima) and soil moisture supply (relative to evaporative demand). These mechanisms are quantified either as thresholds (for survival and regeneration) or multipliers (for growth), based on bioclimatic variables computed from monthly climate normals interpolated three-dimensionally to a 10-minute grid. Growing-season and growing degree day calculations take into account the effects of chilling. The drought calculations also take into account the effects of soil-moisture storage by means of a physically based evapotranspiration calculation coupled to a one-layer soil hydrology model. STASH is used to examine changes in potential range limits under a 2xCO2 climate-change scenario. Associated transient responses at selected sites in the boreal and boreo-nemoral zones of Sweden are also simulated, using the forest gap model FORSKA2. The species-specific survival and regeneration constraints and growth responses of STASH modify the growth, establishment and mortality of trees in FORSKA2. The results obtained in this way differ sharply from the results of conventional forest gap models, where growth rates are assumed to decline to zero at minimum and maximum growing degree day limits. For example, towards the southern limit ofPicea abies (Norway spruce), STASH correctly shows no decline in productivity, but rather an abrupt cut-off corresponding to a chilling requirement during regeneration that is not met further south or west. In transient warming scenarios, this mechanism has the effect that natural regeneration can be blocked due to the warm winters even as yield is increasing due to the longer and warmer summers. STASH predicts drastic changes in species distributions in response to the large climate changes (especially winter warming) expected for northern Europe. Some of the common boreal species (e.g.,Picea abies; Pinus sylvestris; Alnus incana) are unlikely to survive in much of their present range, withdrawing to the far north. Other species already widespread may be able to occupy some of the few sites that are today unavailable to them (e.g.,Betula spp.;Corylus avellana). Other temperate deciduous species such asFagus sylvatica could have dramatic range expansions, potentially occupying large tracts of the present boreal zone. FORSKA2 transient simulations illustrate some of the possible routes towards different types of forest in a changed climate. Some sites in the north show little change in species composition, but sites towards the southern boundary of the boreal zone could develop a new suite of dominants. The degree of sensitivity of a particular site depends both on the climate change prediction and on the transient dynamics of the forest community. Many types of transient behaviour are shown to be possible. Coupled with uncertainties about the future role of dispersal and changes in disturbance rate, the complexity and variety of these transient responses imply a highly uncertain future for the north European boreal forests.
A general description is given of the most important processes occurring in forest communities and of the spatial range and duration of the cycles of particular processes.
In the initiation and course of nearly all processes involved in non-periodical vegetation dynamics a particular role is played by two groups of biotic-biocenotic factors: 1. Behaviour of main forest edificators (oak, hornbeam, spruce and pine); 2. Primary environmental preferences of the big herbivorous animals (bison, red-deer, roe-deer, elk, wild boar).
The range of the particular processes is practically limited by the size of the potential forest phytocoenose, and the duration of a single cycle is determined by the properties of the habitat and the stability of the climate.
The study deals with a small South Swedish deciduous wood (Ulmo-Fraxinetum, Sjögren n.p. 1971), a national park which has been left almost undisturbed during the last 60 years. Since 1925 the number of vascular plants in the area has diminished by 42%. In the tree layerUlmus andFraxinus have increased since 1918 whileFagus has remained fairly constant andQuercus, the former dominant, has become much less important. In the shrub layer youngUlmus are predominant, while the former dominantsCorylus andCrataegus, have diminished markedly. Vegetation analyses of the field layer laid out in a fixed grid system in the years 1935, 1969/70 and 1975/76 show a decrease in both the total number of species recorded and in the number of species per sq. m.Anemone ranunculoides, Aegopodium podagraria andMercurialis perennis are species which have expanded while e.g.Anemone nemorosa, Lamium galeobdolon andGeum urbanum have diminished. Increased shading from the closer tree canopies, increased litter fall, and lower temperature at the soil surface are changes in environmental factors which probably have come about sine 1935 and may be especially important for the field and bottom layer species. The results are discussed in relation to the stability of an ecosystem and to the management of nature reserves.
Lennart Lindgren and Stefan Persson were responsible for the project in 1969–1970 and 1975–1976, respectively. They compiled all the material from these investigations. Skilful assistance was given by Brita Billstein, Mimmi Varga and Tommy Wikberg.
In the strictly protected (since 1853) forest reserve of La Tillaie (Fontainebleau), two site types can be distinguished: Melico-Fagetum on calcareous brown earths, and Fago-Quercetum on podsols. For both sites a 1-ha plot has been studied in great detail. Stem bases, crown projections and uprooted trees have been charted (scale 1:200). For each tree, dbh, heights of crown top, crown bottom, first fork, and vitality parameters were measured. Collation of this map with 15-year-old mapped data on forest structure and a forest reconstruction before the 1967 storm by means of relatively dated trunks, allowed quantification of 15 years' regeneration mosaic shifts. Counts of mound and pit micro-relief caused by the individual uprooting of trees, an examination of their stage of flattening, and the stage of decay of almost-rotted trunks, gave an indication of forest dynamics of both plots back to the 17th Century. The virtually pure beech stands show a heterogeneous regeneration mosaic in which pioneer species are almost absen. Even within the 1-ha plots trees of all sizes occur. Gap phases are most frequent and largest in the Fago-Quercetum. At this site dense Pteridium herb stages can delay forest regeneration for decades. In the period studied phase transition surface was largest in the Fago-Quercetum. The oscillations around an equilibrium are larger in the Fago-Quercetum than in the Melico-Fagetum.
Materialy do poznania zalezności między drzewostanem a glebà w czasie i w przestrzeni (Materials for study of the temporal and spatial relationships between forest stand and soil conditions)
- Włoczewski T.