Introduction

Area limits
Characteristics of European forests
Forest regions and types
What is virgin forest?
Are there really virgin forests in Europe?

Area limits

This website has been limited to Europe, excluding Russia. Remarkable large pristine wildernesses in European Russia include the “Virgin Komi Forests” world heritage site (Europe’s largest virgin forest, totalling 32,800 km² and consisting of Pechora-Ilych Nature Reserve and Yugyd Va National Park), Vodlozersky National Park (4683 km² consisting of virgin boreal forests and cultural landscapes) and Caucasus Nature Reserve (described briefly with Caucasus – Northern Iran) ¹.

Below we call Europe without Russia just Europe, for simplicity. The island groups of Macaronesia, only politically part of Europe, have also been excluded although they are described briefly.

The nomenclature of scientific plant names follows The Euro+Med PlantBase².

Characteristics of European forests

Europe’s climate is influenced by the Gulf Stream, a powerful warm ocean current right up into the far north of Europe, and westerly winds bringing moist air from the Atlantic. The European mountains (the Pyrenees, Alps, Carpathians) are west–east-orientated, allowing these westerly winds to penetrate far into eastern Europe. These factors make Europe warmer than any other place at the same latitudes and the climate relatively oceanic, westernmost Europe being very oceanic.

Throughout Europe the tree flora is poorer in species than either North America or especially eastern Asia in similar sites. The most important reason is thought to be that the European mountains and seas (the Baltic and Mediterranean) are west–east-orientated, preventing the retreat south of many tree species ahead of the advancing glaciers from the north. In addition, the moist warm-temperate region (photo below) is very small in Europe as the drier Mediterranean region begins directly south of the European mountain ranges. Before the Ice Ages, the tree flora of Europe was at least as rich as in North America, though still poorer than in eastern Asia³. Eastern Asia is the only northern moist temperate forest region that shares a long, common border with moist (sub)tropical forests, colonization from the tropics since the Cretaceous period having probably played an important role³. In East Asia the glaciated area was also much smaller because the precipitation there was too low for the accumulation of large glaciers⁴.

Almost 400 native tree species grow in our area, though about 160 of them are apomictic whitebeam (Sorbus) microspecies⁵. The number of tree species capable of reaching at least 20 m is about 80 ⁶. Tree species richness is highest in the north-central Mediterranean region and in the Balkan Peninsula, decreasing to the north and to the west due to the decreasing accessibility to colonization from the ice age refugia^{5 6}.

The mentioned low species richness applies to woody flora only; the herbaceous flora is even richer in Europe than in North America but poorer than in East Asia⁷.

As the European forests are usually composed of only relatively few tree species, it is easy to learn to identify them. Understorey species are more numerous but even there certain species occur repeatedly in similar sites, so it is not difficult to learn to identify the most abundant species.

For different reasons, the shrub layer in mature European forests is often open and the forests are easy to walk (photos below).

Forest regions and types

Dividing forests into exact types is beyond the scope of this website. Thus, we only discuss the three fundamentally differing forest regions. They are, from north to south:

1. The boreal region extends to southern Sweden and northern Belarus. In Scandinavia, the boundary can be defined quite precisely: the southern limit of Norway spruce (Picea abies) and the coinciding northern limit of European beech (Fagus sylvatica) ⁸. In the east, the boundary is more blurry: Norway spruce grows in poor sites south of the boundary and beech does not reach the northeastern corner of the temperate region. Most of Scotland belongs to the boreal zone, too.

Short growing season, long winter, forest mainly composed of conifers, forest floor carpeted by subshrubs, mosses and lichens, forest fires important part of natural dynamics.

2. The temperate region extends in the south to the mountains of the Pyrenees, Alps and Dinaric Alps.

Summer and growing season longer, on lowlands forest mainly composed of deciduous broadleaf trees, undergrowth normally sparse, no forest fires.

3. The Mediterranean region. Lowlands surrounding the Mediterranean Sea.

Dry and hot summer, growing seasons in spring and autumn, evergreen and deciduous broadleaf trees and conifers, forest fires important part of natural dynamics.

What is virgin forest?

According to Buchwald⁹, virgin forest is a forest ecosystem “virtually unmodified by man, and where the degree of former human impact on the forest – including soil and hydrology – has been only slightly more significant than the impacts of wildfire and animals (e.g. beaver (Castor spp.) or megaherbivores), and is no longer obvious. Wildlife inhabits the area with a fairly natural density and species composition, including large herbivores and carnivores.” In practice, however, the forests called virgin forests have quite high variation in human impact: seemingly not disturbed to at least lightly disturbed¹⁰.

Terms with more or less similar meaning include primeval forest, pristine forest and primary forest, the latter usually used for undisturbed tropical forests.

Somewhat less natural forests have been called “near-virgin forests”. According to Buchwald⁹, they are “forest ecosystems untouched long enough to have attained structures, dynamics and species composition similar to virgin forest, even though they may have been significantly modified, e.g. by clearcutting or agriculture at some time in the past… Human impact on the forest structures is not obvious.” (Photos below)

The North American term “old-growth forest” is a bit more complicated. Much of the confusion over its definition may stem from its origins when old growth was a term associated with the temperate rainforests of western North America, which are dominated by big and long-lived trees¹¹ (photo below). Sometimes, like on this website, “old-growth forest” is defined approximately like “virgin forest” (see above) ¹², but “old growth” implies old trees and often old-growth forest is assumed to be composed of old trees, besides being natural^{13 14}. Old-growth forest is also defined as being only a successional stage, without assuming absence of anthropogenic disturbances¹⁵.

On the other hand, “natural forest” only implies that the forest is predominantly composed of self-sown native trees⁹ (photo below). “Unmanaged forest” is just not under active management and “ancient forest” (particularly in the British Isles) has never been cleared for agriculture¹⁶.

Large roadless areas of relatively undisturbed forest have been called “intact forest landscapes” ¹⁷, “frontier forests” ¹⁸ or simply “forested wildernesses”.

These terms have suffered some inflation: especially in countries where no – or very little – undisturbed forest is left “primeval forest” or “virgin forest” may be used as synonyms for “protected forest” even if it has been managed forest a few decades earlier.

Of course, there are no forests on Earth that completely lack anthropogenic influences. Even the most remote wilderness is affected at least by atmospheric pollutants. Of forest regions, temperate and subtropical forests are the most heavily fragmented and disturbed, while boreal forests include the largest amount of relatively undisturbed forest (predominantly in Russia and Canada) ¹⁸.

In conservation biology, certain species are often considered indicators of virgin or old-growth forests: For example, rare beetles or fungi that are bound to typical virgin forest features such as dead wood and old trees are called virgin forest relict species¹⁹. Ironically, such species can also occur outside virgin forest, such as the endangered great capricorn beetle (Cerambyx cerdo), which occurs in Germany mainly in parks because there are almost no forests with very old oaks left.

On this website, the decisive factor is the logging history, or rather the lack of it. The forests we have chosen have had no known logging, or at the most some very limited logging very long ago. In some cases a part of the forest has had logging but the rest has remained unlogged. Dead wood use has been accepted if it happened at least a hundred years ago. Nevertheless, most forests on this website have had no known dead wood use, either. Indirect human influences like browsing of unnaturally numerous herbivores, damage from acid rain in the late 1900s, and unnatural fire regimes have been omitted because their inclusion would exclude most of the Central European forests and all the boreal forests (photos below). This definition perhaps fits better the definition of “untouched forests” than virgin forests⁹. There are two exceptions to these rules: Białowieża has been accepted because of its special status although there has been some tree cutting and Mittelsteighütte has been accepted because of its regional importance, although it has had somewhat more human disturbance than the other sites.

Are there really virgin forests in Europe?

Yes, there are! You have perhaps heard of “Białowieża Primeval Forest”, sometimes called “Europe’s Last Primeval Forest”. Well, there are others and Białowieża National Park is not even the “most primeval” of Europe’s forests. In regard to the existence of virgin forests, Europe can be divided into five zones, here from south to north:

1. Mediterranean lowlands: No virgin forests. Even natural forests are extremely rare²⁰. More than 2000 years ago, the Greeks and Romans had already destroyed much of the original forests¹⁸. As a result of millennia of soil erosion due to clearing, fire, agriculture and pasturing, there is in many places only sparse herbaceous vegetation on nude base rock^{20 21}. The openness of the Mediterranean landscapes and the shrubby vegetation is a product of man, sheep and goat²¹.

2. Mountains of central, eastern and southern Europe: The least disturbed forests of Europe are situated in this zone. Steep slopes and difficult accessibility have been the best protection for forests.

In the Alps, Pyrenees and Apennines the virgin forest remnants are small, the largest continuous area being Rothwald’s “Big Primeval Forest” (2.4 km²) in the Austrian Alps. Even the high altitude regions of the Alps were already settled in the Bronze Age; extensive deforestation happened between the 8^th and 14^th centuries ²². The situation is better in the Carpathians and on the ranges of southeast Europe (photos below). Until a few decades ago, a relatively continuous mountain forest cover was maintained in the Romanian and Ukrainian (partly also in Slovakian) regions of the Carpathians because it was still not operationally or economically viable to conduct logging in these forests²³. At the end of the 19^th century there were in Romania approx. 20,000 km² of virgin forests²⁴ and even in Slovakia thousands of square kilometres²⁵. Recently, however, due to the introduction of modern harvesting technologies, widespread destruction of many previously undisturbed sites has occurred across the Carpathians²³. Romania has the largest area of virgin forests but is still logging them, legally and illegally²³. The largest continuous virgin forest areas there are about 50 km².

In the Central European virgin forest remnants, the most important non-natural factor is over-population by large herbivores due to lack of predators. Of the montane forest tree species, European silver fir is the most heavily browsed, followed by sycamore maple (Acer pseudoplatanus), in the shrub layer raspberry and blackberries (Rubus), while beech and spruce are only slightly damaged^{26 27}. Thus, the high density of the herbivores is resulting in remarkable shifts in forest composition. In eastern Europe predators are present, herbivore populations lower, with natural understories and tree regeneration (photo below). Silver fir also regenerates in Pyrenean virgin forest remnants. In parts of Central Europe, exposure to sulphur dioxide in the latter half of the 20^th century has also caused a decline of fir²⁸, which is also considered the most sensitive tree species to air pollutants²⁹. A strong reduction of the emissions during recent decades has resulted in increased fir vitality²⁸.

European spruce bark beetle (Ips typographus) has destroyed large areas of subalpine Norway spruce forest in recent years almost everywhere (photo below). The populations of this bark beetle living on spruce are usually small, but may rapidly increase and kill large areas of old spruce forest if breeding conditions improve, e.g. through climate warming²⁷ and increased breeding space due to the spruce monocultures. Basically, however, the mass outbreaks of bark beetles are natural disturbance events in virgin conifer forests, which destroy the old spruces but not the forest – on the contrary: young virgin spruce forests after a bark beetle outbreak are just as species-rich as the old ones³⁰. Nevertheless, in many protected areas (e.g. Bavarian Forest and Harz national parks, Germany), large forest areas are destroyed at least outside the core zones as bark beetle control measures¹⁹.

3. Central European flatlands: No virgin forests. Strictly speaking not even the famous Białowieża is virgin forest. Slash-and-burn agriculture was already being practised in Central Europe by at least 3700 BC ³¹. After that almost every suitable piece of forest has been cleared at least once³². On flatlands very few sites have been strictly protected for more than a few decades³³ (photo below). However, on lower mountain slopes there are virgin forests whose lower parts can be considered to be in the lowlands, e.g. Dobra in Austria and Boky in Slovakia.

Logging, grazing, unnaturally high herbivore populations and particularly leveeing (photo below) have changed floodplain forests profoundly. Besides the Mediterranean lowland forests, the floodplain forests have suffered the most human destruction³⁴. Near-virgin swamp forests still occur, for example in Białowieża National Park.

4. Boreal zone: There are virgin forests but only very few (photo below). Slash-and-burn agriculture earlier and forestry later have affected almost every piece of forest. The largest virgin forests are about 10 km². Nevertheless, even these forests are not in their entirely natural condition because their forest fire history is unnatural. In the slash-and-burn era the fire interval was unnaturally short as fire sometimes escaped from slash-and-burn to the neighbouring virgin forest³⁵. After the introduction of fire prevention and the end of the slash-and-burn era, fires have ceased almost completely. The exclusion of forest fires turns forests from fire disturbed stands into fire-free refugia; the absence of forest fire as a disturbance agent may thus create artificial vegetation states with little resemblance to the primeval forest landscape³⁶.

5. Northern Fennoscandia: Europe’s only true wildernesses are located in the north-boreal zone in northernmost Fennoscandia. The extent of the largest of these is thousands of square kilometres (photo below). They have remained intact simply because extensive agriculture and forestry were not profitable due to the short growing season and the slow tree growth. Here and there some trees may have been felled and some dead wood used for campfires but this use is entirely negligible in relation to the extent of the forests and the amount of dead wood.

The biggest non-natural factor is reindeer browsing, even in protected areas. The reindeer has been semi-domesticated in northern Fennoscandia for at least 1000 years. The most important damage by the excessive reindeer herds of the last decades has been a virtual elimination of the lichen cover on drier forest types (photos below). This can even be seen in satellite images in places along the northern Finnish–Russian border as the excessive herds are missing on the Russian side and on the border zone resulting in light-coloured lichen cover (see e.g. here). Arctic downy birch (Betula pubescens var. pumila) stands have also suffered from the browsing.^{37 38 39} Forest fires are suppressed as in the more southern parts of the boreal zone. Thus, the wildernesses of northern Fennoscandia are not as pristine as the vast wildernesses of Russia, Canada and Alaska with their natural fire regimes and absence of semi-domesticated animals.

KR & TM

References:

1. Butorin, A. (1998): World Natural Heritage Areas in Russia. In Dömpke, S. & Succow, M. (eds.): Cultural Landscapes and Nature Conservation in Northern Eurasia. NABU.
2. https://www.emplantbase.org
3. Latham & Ricklefs (1993): Continental Comparisons of Temperate-Zone Tree Species Diversity. In Species Diversity in Ecological Communities: Historical and Geographical Perspectives. University of Chicago Press.
4. Nilsson, T. (1983): The Pleistocene. D. Reidel Publishing.
5. Rivers, M. C. et al. (2019): European Red List of Trees. IUCN.
6. Svenning, J.-C. et al. (2010): Geography, topography, and history affect realized-to-potential tree species richness patterns in Europe. Ecography 33: 1070-1080.
7. Mutke, J. et al. (2010): European Plant diversity in the global context. In Settele, J. et al. (ed.): Atlas of Biodiversity Risk. Pensoft.
8. Sjörs, H. (1999): The background: Geology, climate and zonation. In Rydin, H, Snoeijs, P. & Diekmann, M. (eds.): Swedish plant geography. Acta Phytogeogr. Suec. 84.
9. Buchwald, E. (2005). A hierarchical terminology for more or less natural forests in relation to sustainable management and biodiversity conservation. Proceedings: Third expert meeting on harmonizing forest-related definitions for use by various stakeholders. Food and Agriculture Organization of the United Nations, 17–19 January 2005.
10. Rouvinen, S. and Kouki, J. (2007): The Natural Northern European Boreal Forests: Unifying the Concepts, Terminologies, and Their Application. Silva Fennica, 42(1): 135-146.
11. Hilbert, J. & Wiensczyk, A. (2007): Old-growth definitions and management: A literature review. BC Journal of Ecosystems and Management 8(1):15–31.
12. Dudley, N. (1992): Forests in trouble: A review of the status of temperate forests worldwide. WWF.
13. Leverett, R. (1996): Definitions and History. In Davis, M. B. (ed.): Eastern Old-Growth Forests. Prospects for Rediscovery and Recovery. Island Press.
14. Hunter, M. (1989): What constitutes an old-growth stand? Journal of Forestry 87: 33-5.
15. Oliver, C. D. & Larson B. C. (1996): Forest Stand Dynamics. Wiley.
16. Sabatini, F. M. (2018): Where are Europe’s last primary forests? Diversity and Distributions, May 2018.
17. http://www.intactforests.org/
18. Bryant, D., Nielsen, D. & Tangley, L. (1997): The Last Frontier Forests: Ecosystems and Economies on the Edge. World Resources Institute.
19. Müller, J. et al. (2018): Increasing disturbance demands new policies to conserve intact forest. Conservation Letters, 2018;e12449.
20. Polunin, O. & Walters, M. (1985): A guide to the vegetation of Britain and Europe. Oxford.
21. Mayer, H. (1986): Europäische Wälder. Gustav Fischer.
22. Parviainen, J. (2005): Virgin and natural forests in the temperate zone of Europe. For. Snow Landsc. Res. 79, 1/2: 9–18.
23. https://www.remoteforests.org
24. Veen, P. et al. (2010): Virgin forests in Romania and Bulgaria: results of two national inventory projects and their implications for protection. Biodivers Conserv 19:1805–1819.
25. Korpel’, Š. (1995): Die Urwälder der Westkarpaten. Gustav Fischer Verlag.
26. Standovár, T. & Kenderes, K. (2003): A review on natural stand dynamics in Beechwoods of East Central Europe. Applied Ecology and Environmental Research 1(1–2): 19–46.
27. Fischer, A., Marshall, P. & Camp, A. (2013): Disturbances in deciduous temperate forest ecosystems of the northern hemisphere: their effects on both recent and future forest development. Biodivers Conserv 22:1863–1893.
28. Elling, W. et al. (2009): Dendroecological assessment of the complex causes of decline and recovery of the growth of silver fir (Abies alba Mill.) in Southern Germany. For. Ecol. Manag. 257: 1175–1187.
29. Wentzel, K. F. (1980): Weisstanne = immissionsempfindlichste einheimische Baumart. Allgemeine Forstzeitschrift 35, 373–4.
30. Hilmers, T. et al. (2018): Biodiversity along temperate forest succession. Journal of Applied Ecology, 2018;55:2756–2766. DOI: 10.1111/1365-2664.13238
31. Ellenberg, H. (1996): Vegetation Mitteleuropas mit den Alpen. Ulmer.
32. Küster, H. (1998): Geschichte des Waldes. Verlag C. H. Beck.
33. Christensen, M. et al. (2005): Dead wood in European beech (Fagus sylvatica) forest reserves. Forest Ecology and Management 210, 267–282.
34. Sauvain, R. et al. (2011): Naturwälder als Lebensraum. In Brang, P., Heiri, C. & Bugmann, H. (eds.): Waldreservate: 50 Jahre natürliche Waldentwicklung in der Schweiz. Haupt.
35. Keto-Tokoi, P. & Kuuluvainen, T. (2010): Suomalainen aarniometsä. Maahenki.
36. Linder, P. (1998): Structural Changes in Two Virgin Boreal Forest Stands in Central Sweden over 72 Years. Scand. J. For. Res. 13: 451-461.
37. Engelmark, O. & Hytteborn, H. (1999): Coniferous forests. In Rydin, H, Snoeijs, P. & Diekmann, M. (eds.): Swedish plant geography. Acta Phytogeogr. Suec. 84.
38. Rikkinen, J. (2019): Metsät Suomen luonnossa. Otava.
39. Vätsärin erämaan hoito- ja käyttösuunnitelma (2008). Metsähallitus.