Virgin and natural forests in the temperate zone of Europe
Jari Parviainen
Finnish Forest Research Institute, Yliopistokatu 6, P.O. Box 68, FIN-80101 Joensuu, Finland.
jari.parviainen@metla.fi
Abstract
Virgin forests are rare in the European temperate zone due to the continuous use of forests historically and to high population densities. Such forests are those whose structure and dynamics developed untouched by humans under natural conditions. Natural forests have developed and regenerated with natural succession, but can show anthropogenic influences from the past.
Scattered relics of virgin forest still exist in remote areas, in mountainous areas and wetlands, especially in the Balkans, Alps and Carpathians. The latest estimates show that there are about 0.3 million ha of virgin forest (0.4 % of the total forest area) left in strict forest reserves and other protection areas in the temperate zone of Europe. The countries with the highest proportion of strictly protected areas are the Slovak Republic, Bulgaria, Albania, Slovenia and the Czech Republic. Both protected forests networks and close-to-nature silviculture are needed to main- tain forest biodiversity. Rare and vulnerable remnants of virgin forests can only be protected by medium or large reserves.
Keywords: virgin forest, natural forest, strict protection, protection networks, biodiversity
1 Introduction
Temperate forests in Europe cover a large bioclimatological spectrum, ranging from oceanic to continental forests, from floodplain to mountain forests up to the alpine timberline. The Atlantic climate in the west turns into a continental climate with decreasing humidity and wider temperature variation in the eastern part of Europe. The natural composition of tree species is governed by competition with other species, the history of migration modified by mountain barriers, edaphic factors and insects, climatic conditions such as drought periods in summer, frost dryness and late frost, as well as the herbivorous population density (SCHMIDT-VOGT 1987). Currently about 26 % of the total area in the temperate zone is covered with often fragmented forests.
Virgin forests are rare in the European temperate zone due to the continuous use of forests historically for thousands of years and to the high population densities. The develop- ment of human settlements has directly affected forests in central Europe. Even in the Alps people had already settled high altitude regions in the Bronze Age (2500–900 B.C.). They obtained food by creating and using alpine meadows for grazing cattle (KRAL1979).
Generally, forests decreased by approximately one third of their original area in central Europe over only a few centuries during the Middle Ages. In the alpine region extensive deforestation occurred in waves between the 8thand 14thcentury. During the Middle Ages the upper altitudinal line for cereal growing and cattle breeding was higher than today because of the favourable climate. The human-induced lowering of the upper timberline in combination with heavy browsing and damage from fires is what has had the most severe impact on natural forest succession (KRAL1971, 1979).
High altitude permanent settlements were abandoned in the 16thcentury as the climate conditions became unfavourable. As a consequence, the use of alpine meadows decreased rapidly. At the same time, there was an increasing demand for wood, firstly for salt pro- duction, later on for charcoal production for the expanding iron industry and finally for construction and firewood in the expanding settlements and towns. This led to a marked intensification of harvesting. During the peak of the mining industry in the 15th, 16thand 17th centuries, large-scale clear cuttings coupled with uncontrolled natural regeneration led to a further decrease in forested area. Spruce was favoured as an economically important species and was also regenerated by planting. Pollen analysis and archive material show an impover- ishment of the natural forests during this period. Scattered relics of native forests, however, have survived in mountainous areas and wetlands, especially in the Balkan, Alpine and Carpathian biogeographic regions (DIACIand FRANK2001; PARVIAINENand FRANK2003;
SPIECKER2003).
At present in some countries of the temperate zone, such as in Denmark, the United Kingdom, Ireland and the Netherlands, forest cover is only about 10 % of the total area, while in Austria, Estonia, Latvia, Liechtenstein, Slovakia and Slovenia forest cover exceeds 40 %. In Austria, Ireland, Poland and the United Kingdom more than 60 % of the forest area is dominated by conifers while in Bulgaria, Croatia, France, Hungary, Luxembourg, Romania and the Republic of Moldova more than 60 % of the forest area is dominated by broadleaved trees. High forest, which are generally of seed or seedling origin and normally develop a high closed canopy, is the most common silvicultural structure category, although in Bulgaria, France, Liechtenstein, the Republic of Moldova and the Ukraine coppice forests and coppice with standards contribute to more than 40 % of the forest area. High forests are mainly even aged. In a few countries, namely Croatia, Germany, Liechtenstein, Slovakia, Slovenia and Switzerland, the area of uneven-aged forest amounts to 15 % or more of the total forest area (Forest resources of Europe, …2000; PUUMALAINEN2001; PUUMALAINEN
et al.2003).
2 What kind of natural forests are there in the temperate zone of Europe?
2.1 Basic definitions of natural forests
In order to find a common basis for discussions on natural forests, the terms and definitions must be described in an international context. The different historical development of forests, forest utilization, settlements, and management regions and the variation in forest ecosystems means that national classifications vary. For international comparison it is help- ful to categorize the terms according to whether they focus on origin and development or on human influence and the management of forests (see Ministerial Conference 1994; SCHUCK
et al.1994).
The concept of “naturalness” refers to how natural a forest is. The naturalness of a forest ecosystem or of the vegetation can be defined as the extent to which the species composition of the existing vegetation corresponds to that of the potential natural vegetation on the same site (Naturnähe Österreichischer Wälder 1997). The term “hemeroby” is often used for the purpose of defining the degree of human influence on forests. Hemeroby includes all anthropogenic influences such as the effects of management, the impact of cattle grazing, game browsing, tourism and other kinds of human impact. The degree of naturalness can
vary from “virgin forest” (extremely high degree of naturalness) to man-made plantations of exotic tree species (very low degree of naturalness). Austria was the first country in Europe to carry out an inventory during the early 1990’s on the naturalness of its entire forest (GRABHERRet al.1998). From the current and historical data and records on forest struc- tures, it is clear that the majority of forests in Central and Eastern Europe have been altered or modified by humans (PETERKEN1993, 1997).
“Virgin forest” can be defined as follows: it is original in its structure and has developed untouched by humans under natural conditions. Virgin forest is not limited only to the climax stage, although the majority of virgin forests are old-growth forests. The terms
“primeval forest”, “primary forest” or “pristine forest” are often used interchangeably with the term “virgin forest” (SCHUCKet al.1994).
The term “forest undisturbed by man” has been recommended, especially by the Food and Agriculture Organization of the United Nations, FAO (Forest resources of Europe, … 2000), and the Ministerial Conference on the Protection of Forests in Europe MCPFE (1993), and this term is seen often as a synonym for virgin forest. The definition of undis- turbed is, however, less strict than the definition of virgin forest. “Forest undisturbed by man” is subject to natural forest dynamics, and the area is large enough to maintain its natu- ral characteristics. Moreover there has been no known significant human intervention or the last human intervention was long enough ago to have allowed the natural species and processes to become re-established.
“Natural forests” develop and regenerate with natural succession, but can show anthro- pogenic influences from the past (see SCHUCKet al.1994). Natural forests always originate from the original forest cover, e.g. the forests are reproduced naturally or regenerate nat- urally (they are not modified by sowing or planting). The difference between “virgin” and
“natural” forests has to do with past human influence. The term natural forest is more relevant in practice, as some kinds of human influence can nearly always be found in European forests.
“Ancient forest” and “semi-natural forests” are the terms most commonly used in Great Britain, and are sometimes found in the scientific literature in other European countries.
“Ancient forest” refers to sites which have been continuously covered by forests for several hundred years or at least since the time when reliable maps were first made. Some may be remnants of prehistorical woodlands whilst others arise as secondary woodland on ground cleared at some time in the past (PETERKEN1993; Forestry Commission 1994). “Semi-nat- ural forests” are affected by human influence, but neither the stand composition nor the structure has been directly or indirectly modified. Stands are composed predominantly of native trees of local origin. They are the result of natural regeneration or selective thinning or also, in some cases, of supportive planting (SCHUCKet al. 1994; Forestry Commission 1994). Some examples of non-fragmented virgin forest communities in Central, East and South-East Europe are (SCHMIDT-VOGT 1991; LEIBUNDGUT 1982, 1993; KORPEL 1989, 1995; DIACI1999; PARVIAINENet al.1999):
– The spruce-fir-beech forest, “Perucica”, in National Park Sutjeska, Bosnia-Herzegovina – The spruce-fir-beech forest, “Slatiora” in Suceava, Romania
– The fir-beech forest, “Rajhenavski Rog” in Koãevje Rog, Slovenia
– The spruce-fir-beech forest, “Kubany” in Boubin, Nature Reserve, Czech Republic – The spruce forest, “Scatlé/Brigels”, Graubünden, Switzerland
– The spruce-fir-beech forest, “Dobroc”, Slovakia
– The beech forest, “Uholka” in the Carpathian Biosphere Reserve, Ukraine – The basswood forests in the Bialowieza National Park, Poland
2.2 Minimum size for non-fragmented natural forest
An important aspect for defining a non-fragmented, individual virgin/natural forest stand is the minimum size. Often virgin or natural forest stands are protected in core areas of large, previously managed, but now protected forests, while continuous untouched forest areas cannot be found because of the long-term utilization of the forests. Human influence has also resulted in the fragmentation of forests into islands amongst other land-use categories and in the decline of naturalness.
The natural phase cycle is the main guideline for defining the minimum structure area, e.g. the smallest area which is needed to allow, in the long term, all forest development phases to occur. Studies of minimum areas have been published for natural forests in e.g. the Czech Republic, Slovakia and Hungary, based on gap dynamics.The frequency of gap forma- tion and the statistical gap-distribution during long periods was used to calculate a minimum structure area of about 40 ha for the Carpathian beech forest (HOLEKSA1993).This is similar to a result obtained in modelling the structure and dynamics of beech forests (KOOP1989).
Phase mosaic gaps can be as small as 50 m in diameter (see BÜCKING1997, 2003; KOOP
1989). A further important factor which determines the size and stadial age of the phases and therefore also the minimum area is the growth potential of the forest site.The larger and more homogeneously the trees grow, the larger the single patches and, consequently, the larger the minimum area. This means that on poor sites the minimum area is much smaller than on rich sites. From the financial point of view, the consequence is that representative reserves on poor or dry sites are much less expensive than reserves on rich sites when only forest structure is considered. This is one of the reasons why very productive forest types are poorly represented in strict forest reserve networks (BÜCKING1997, 2003).
One open question is, however, how to deal with large-scale disturbance events, i.e. with abiotic disturbances like wind throw, avalanches, land-slides, erosion or fire, or with biotic events like beetle calamities, diseases and pests. In order to buffer such events, the minimum structure area must be increased by at least a factor of five to ten, though many of these large-scale processes can only be protected in the form of national parks. Similarly, concerns for animal faunas and the need of some species for larger blocks of unfragmented forest can also multiply tremendousely the size of needed reserves. As can be seen from Table 1, the
Table 1. Minimum areas of strict forest reserves in the temperate zone of Europe based on research results for forest site and development cycle mosaics (data as extract from BÜCKING2003).
Based on forest structure studies Minimum area, hectares
Extreme sites 5–20 ha
Mixed forests 10 ha
Beech-oak forests
Beech forests 50 ha
Beech-fir forests
Mixed mountain forests 70–100 ha
Mixed alpine forests
Based on faunistic and site studies
Micro- + Mesofauna (p.p. Macrofauna) 50–100 ha Large mammals/birds >>>100 ha Typical site mosaic or landscape fraction 100 ha
minimum areas are comparatively small in multi-tree species, mixed forests with oak or valuable broadleaves. The areas are large in forests with just a few species such as mountain beech, beech-fir, or mixed mountain beech-fir-spruce forests (see the compilation by BÜCKING 2003; ZUKRIGL et al. 1963; MAYER and NEUMANN 1981; SCHUCK et al. 1994, ELLENBERG1999).
3 The size and distribution of natural/virgin forests in the temperate zone
The objectives and the degree of forest protection vary widely amongst European countries due to the wide range of different vegetation zones, tree species composition and human impact on forests. The terms “protected”, “unprotected” and “protection” tend to be inter- preted inexactly without consistency by different countries and organisations.
Of all the protected forests in Europe, the most interesting category is the strictly protected forests. In strictly protected forest reserves, the forests are left to develop freely in a state which is as original as possible. Forests are left to develop “freely” in various categories of protected areas: strict reserves, nature reserves, core areas in national parks, old forest pro- tection areas, wilderness areas, cultural monument areas, etc.
The COST (European Cooperation in the Field of Scientific and Technical Research) Action E4 “Forest Research Network”, carried out in 1995 to 1999, was the first systematic analysis of the strictly protected forest areas in Europe. Over 100 scientists and nature conservation administrators from 19 participating COST member countries, in addition to 8 Central and Eastern European countries and Russia, participated in the Action (BROEKMAYER et al.1993; PAULENKA and PAULE 1994; PARVIAINEN et al.1999, 2000a, 2000b; DIACI1999; European Commission 2000).
Scattered relics of original forest cover still exist in remote areas, in mountainous areas and wetlands, especially in the Balkan, Alpine and Carpathian biogeographic regions. The newest estimates show that there are about 0.3 million ha virgin forests (0.4 % of the total forest area) left in strict forest reserves and other categories of protection in the temperate zone of Europe (Fig. 1). The majority of these forests are mixed fir-beech, or fir-spruce- beech forests. There are over 2500 strict forest reserves. The average size is about 100 ha.
The size typically varies between 40 and 100 ha (DIACI 1999; PARVIAINEN et al. 1999;
PARVIAINENand FRANK2003).
The countries with the highest proportion of strictly protected areas with no active inter- vention in relation to their overall forest area are the Slovak Republic, Bulgaria, Albania, Slovenia and the Czech Republic. In Austria the nation-wide inventory in the 1990’s showed that 3 % of the Austrian forests are in their natural condition, but they are not always located in protected areas (GRABHERRet al.1998).
Difficulties interpreting protected forest statistics arise because of the array of different definitions and the composition and location of protected forest areas. In many cases, game control, fire control, free access to the reserves and the removal of invading exotic species is allowed. The only common nominator for a strict reserve is that there is no silvicultural management (PARVIAINENet al.2000a).
During the last five years, political interest in protected forests has increased appreciably on both the international and national level. The analysis of the category “strict forest reserves” in COST E4 was one starting point for further analysis and for the harmonization of protected forests within Europe (PARVIAINENand FRANK2003).
0 1 2
Albania
Belgium (Fland.)
Bulgaria
Ireland
Czech
Slovenia
The Nether.
Slovak
UK
Romania
Germany
Austria
Hungary
Bosnia-Herzeg.
Croatia
France
Switzerland
Poland
in % of total forest area
Strictly protected forest areas to be found in strict reserves, nature reserves, core areas of national parks or other categories of protected forests (COST E4)
0 1 2 3 4 5
Belgium Bosnia-Herzeg. Denmark Germany Ireland Italy Romania Austria Croatia France Hungary UK Switzerland Poland Czech Netherlands Slovenia Albania Bulgaria Slovak
MCPFE classification for protected forests: no human intervention
in % of total forest area
Fig. 1. Virgin and natural forests in the temperate zone of Europe according to the data on strictly protected forests (COST E4 Action 1995–1999) and the MCPFE classification categories of “no human intervention” in 2003.
A working group established by the Liaison Unit of the Ministerial Conference on the Protection of Forests in Europe (MCPFE) has developed a new classification system for forest protection in Europe (Vienna Declaration and Vienna Resolutions 2003). The classifi- cation of the World Conservation Union IUCN, the TBFRA (Temperate and Boreal Forest Resources Assessment) data collection procedure, the EEA (European Environmental Agency) classification for CDDA (Common Database for Designated Areas) and the findings of COST E4 were used as a basis for this new classification. The classification consists of three categories: protected forests with the management objective “biodiversity”,
“protection of landscapes” and of specific natural elements, and “protective functions” (soil, water, natural hazards). This classification has been used for comparisons and discussions in the 4th Ministerial Conference organized in 2003 in Vienna, Austria. The results of the MCPFE classification with the category biodiversity, “no human or minimum intervention”
were quite similar to those with the category “natural forests” in the temperate zone of Europe in the COST E4 survey (State of Europe’s Forests 2003, Fig. 1).
4 Conclusions
Virgin and natural forests are important remnants of valuable and rare forest ecosystems.
They provide a basis for close-to-nature silvicultural research and applications, for planning national protected forest networks and for providing a reference for naturalness inventories of “normal multifunctional” forests. It is generally accepted that natural forests are the basic model for the realisation of close-to-nature silviculture. In strict forest reserves, the devel- opment cycle of natural forests can be observed, elucidated and analysed, and the findings subsequently mimicked in multifunctional forests. Forest management is generally based on a combination of knowledge derived from research on natural forests and silvicultural experiments in conventional forest areas (see SCHÜTZand MATTER1992; PARVIAINENet al.
2000b).
Complementing the available networks of protected forests is one of the main goals of current forest policy. However, there is no single, uniform or internationally agreed target with respect to the proportion (e.g. 5 or 10 %) of the country’s forest which should be strictly protected. Rare and vulnerable forests, especially remnants of virgin forests, can only be pro- tected by medium or large reserves. The focus of debate in Europe appears to be shifting from “total” large-scale protection in segregated areas to “precision protection” and to restoration of available protected areas, and to combining protection and timber production in integrated forest management.
Taking a static approach and protecting only old forests will limit our efforts to just one important segment of the forests and may increase the risk of outbreaks of insects, or of fire and storm calamities in the forest and surroundings. To guarantee a variety of habitats and development stages of protected forests it is necessary to preserve young valuable forests as well. Protecting or generally maintaining biodiversity should be seen as a dynamic process in order to ensure the dynamic evolution of different species and ecosystems parallel to the forest development cycle.
Maintaining biodiversity in forested areas can be achieved by having an adequate network of protected areas and by implementing large-scale close-to-nature silvicultural management which integrates conservation, production and non-production functions (see Ministerial Conference on the Protection of Forests in Europe 1993). Multifunctional forests have the greatest value for preserving living organisms, as they represent 80 to 90 % of the forested area in most European countries. Close-to-nature silviculture produces wood economically and efficiently and, at the same time, provides large-scale protection and conservation by enriching biodiversity at all spatial levels.
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Accepted February 21, 2005
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