Here is some information from works that have shaped a perspective of the given topic. This topic was researched by many authors. During study of their work we can detect obvious intellectual shift which was influenced by the degree of knowledge about historical development of forests and natural forest dynamics. This contribution is based on the study of many older works and present knowledge about development of semi-natural forest ecosystems.ZLATNÍK (1938) summarizes previous opinions about the virgin forest in his pamphlet “Virgin forest and managed forest”:
TSCHERMAK (1910) considers virgin forest as “a forest that still exists in such state which it would obtain without any human intervention, i.e. by natural development of both physical surface and related vegetation, under the influence of the given climate and further by organism competition and other factors influencing natural distribution of plants”.
RUBNER (1918) states “Virgin forest can be understood as a large, pristine forest area or a forest where human intervention never occurred and the appearance and disappearance of individuals was caused only by nature”.
SCHENCK (1927) defines as virgin forest “every forest which a cultural man has not yet penetrated to fell trees” because apparently indigenous Rusyn from Carpathian Ruthenia is said to belong to the virgin forest in the same way as a deer, moose, caribou and forest trees!
MÜLLER (1929): “Virgin forest is forest vegetation so far unaffected by a cultural man”. According to this definition, he recognizes as virgin forests also secondary mountain forests in Bulgaria which were burned down by Turks out of strategic reasons and then spontaneously regenerated. The same overview, more brief and without any explanation, can be found in Forest Encyclopaedia (KONŠEL 1940) under the term “virgin forest”.
KONŠEL (1931) in his work divides forest as cultivated and uncultivated. He further divided cultivated forests to– unplanted; – artificially established. The category uncultivated forests, or also natural forests, included: – virgin forests or natural primary forests; – newly unplanted and uncultivated forests or natural secondary forests.
The distinguishing criterion according to Konšel is cultivation and not logging. Natural forest stops being natural if its essence is touched by cultivator’s hand. KONŠEL (1940) states in the Forest Encyclopaedia under the term “Nature”: “Therefore we distinguish two terms: “natural” and “near-natural”. The first reflects origin and source, the second derived characteristics. Thus natural forest has been established by nature without any human involvement while near-natural forest can be established by humans but its natural characteristics have not been blurred by artificial or intentional formation”.
ZLATNÍK (1938) on the basis of his own experience from Carpathian Ruthenia used his own forest classification reflecting origin. He introduced a term near-natural forests which he further divided according to the degree of condition to
a) virgin forests, i.e. forests that have never systematically been logged and do not bear signs of such logging with the exception of felling individual trees along a road or forest edge, where no trees have been planted or sewed successfully and where there are no signs of grazing or the grazing does not have a substantial impact on tree recruits.
b) Grazed virgin forests – he included them into the virgin forests but grazing has a negative impact which is represented by lack of tree recruits, changes in soil vegetation due to fertilization and trampling by livestock.
c) Near-natural forests disturbed by logging – i.e. forests where a substantial part of stems was selected but only at some places and the forest was not further cultivated; if a partial artificial restoration was implemented it was only by sowing domestic seed. In these forests, if they were mixed, the proportion of trees changed and therefore mixed forests with the prevalence of coniferous species became mainly deciduous ones; coniferous species were felled more than hard wood and deciduous species responded with vigorous regeneration. Regular felling in these forests is not present; direct signs of the logging have usually disappeared so these forests look like intact virgin forests. As in the case of virgin forests, this type of forests is further divided according to the degree of grazing.
Later ZLATNÍK (KOLEKTIV 1959) presented following definitions:
a) We call primary forest biocoenosis or biogeocoenosis as a virgin forest. There are no apparent disturbances of any kind in the virgin forest in the sense of original mature forest biocoenosis.
b) Near-natural forest includes both original and modified forests considering that species composition in the modified forest is qualitatively in accordance with original forest (consistency in quantitative representation and in the spatial and age structure is unnecessary).
c) Natural forest corresponds with a forest that was created or regenerated entirely by natural processes.
HEJTMÁNEK (KOLEKTIV 1959) defines:
a) Virgin forest as a forest without any human influence or influenced only very slightly.
b) He combines the meaning of the terms “virgin forest” and “natural forest” in further text.
MÁLEK (1965) on the basis of studying many older works researched in detail the terminology of forests “originality”. He focused namely on the forest composition:
a) Original forest composition (indigenous forests, virgin forests) – existed before strong human interventions, i.e. before landscape colonisation. Some smaller human interventions in the period before permanent settlement, e.g. livestock grazing, logging at the edges of the virgin forest or along the paths in the forest, did not affect changes in tree composition. The tree composition reflects natural settings even today.
b) Natural forest composition (natural forests) – was created by natural regeneration of forests influenced by man, especially in the period before the forest culture. It means that no artificial restoration by either sowing or planting was carried out – forest regeneration was left exclusively to nature. Human influence was represented mainly by livestock grazing, litter raking and other activities. The species composition depends on the intensity of the interference (grazing etc.) and does not have to reflect the natural settings.
c) Near-natural forest composition (near-natural forests) – reflects natural settings but it can be achieved by human cultivation (artificially established forest with near-natural composition).
Also botanists (especially geobotanists) are interested in the relevant terminology. However, they do not differentiate human interference in the forest in a detail.
NEUHÄUSLOVÁ-NOVOTNÁ et NEUHÄUSL (1969) distinguish:
a) original forest = virgin forest – forest type that exists at a certain locality and has not been influenced by a man at all or only in a small rate
b) natural forest – its species composition reflects natural settings which can be influenced by a man
c) original community – a phytocoenosis that existed at a certain place before the beginning of human intervention
d) near-natural community – a phytocoenosis whose composition has not been influenced by a man either directly or indirectly and which exists in the balance with its environment. Since we cannot determine in certainty whether the present vegetation has been affected or not we use this term also for communities close to near-natural phytocoenosis.
VYSKOT et al (1981) also use three-fold categorization:a) Virgin forest is defined as a forest untouched by a man and as such it does not exist in any region with ancient human settlement. The term virgin forest expresses not only elimination of any human activity but also exclusion of any traces of former changes in its composition and structure caused by e.g. fire from lightning, windfalls etc. Forests affected by these events are called secondary unplanted forests (without any human influence on their formation and evolution).b) Natural forest i.e. forest of virgin forest appearance is second category. This category has the same species composition, spatial and age structure as a virgin forest. It might have been “selectively” logged in the past but it has maintained the structure of all-aged forest. The composition and the structure have returned to more or less original state throughout the centuries. It is a forest that is entirely the work of nature.c) Near-natural forest is distinguished from natural forest. It is a forest with species that could have rooted, grew and regenerated under certain conditions related to the environment and mutual relations including competition, and repeat the process without help of man. Near-natural forest reflects wider concept than natural forest which is also independent and capable of self-regulation. Near-natural forest does not have to be old or all-aged and can bear traces of human activities.
MÍCHAL (1983) distinguishes:
a) undisturbed forests – fully unaffected by human intervention (virgin forest sensu stricto)
b) natural forests – affected by human activities only marginally and thus keeping their species composition as well as spatial and age structure. These forests represent an image of potential natural vegetation because they were established or regenerated exclusively by natural conditions. If any developmental shifts occurred (e.g. after fire caused by lightning, logging with leaving the logged areas to the spontaneous development) they cannot be detected after a longer period.
c) near-natural forests – in the narrower sense (corresponding to the German “naturnahe Wälder”) they include forests with more or less natural species composition but without spatial and age structure. These are less differentiated than in b) natural forests. Near-natural forests have been more or less affected by man. They have been logged and grazed by cattle and have been regenerated either naturally or artificially. Since natural mutual ecological linkages between species have been preserved regardless the human influence, these forests are capable of spontaneous regeneration and they could gradually become natural forests providing that they would not be further affected by man.
PRŮŠA (1990) adopts Míchal’s classification (1983), refining it in some details but his approach is in principal identical to that of Míchal.
PODRÁZSKÝ et al. (2001) define basic concepts as follows:
a) Natural forest is a forest with human influence (a virgin forest) both in past and present period. Therefore it is a forest without anthropogenic (nowadays anthropogenic direct) influence which has been developing only by spontaneous evolution defined as natural.
b) Near-natural forest is a forest with indigenous species composition, its structure and compositions have been slightly altered but its self-regulation ability has not been disturbed.
c) Semi-natural forest is a forest which has been spontaneously developing to the higher stages with absence of any human activities. The species composition is semi-natural and the structure is secondary. It is relatively resistant.
d) Spontaneous forest (ecosystem) development means exclusion of all intentional human interventions connected with management. Further development is influenced only by natural processes and factors that might be potentially anthropogenically affected.
e) Unrestrained development can be substituted with spontaneous development. Unrestrained (spontaneous) development can occur in the forests with both natural and unnatural composition, and spatial or age structure.
f) Natural development means spontaneous development of forest stands that correspond to their habitat structure and dynamics and where used processes and factors are minimally affected by man.