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Petrified Forest of Lesvos

Date de soumission : 16/01/2014
Critères: (vi)(vii)(viii)(x)
Catégorie : Mixte
Soumis par :
Permanent Delegation of Greece to UNESCO
Etat, province ou région :
Region of North Aegean, Regional Unit of Lesvos and Limnos
Ref.: 5858
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Description

Located on the island of Lesvos (North Aegean Region), one of the most important natural heritage monuments in the world, the Petrified Forest of Lesvos, is a unique testament to the ecosystem that once existed in the Aegean region during the Miocene Epoch. The forest consists of hundreds of fossilized trunks, standing or downed, coniferous or fruit-bearing, which are scattered over an area of 15,000 hectares in major concentrations within the protected region and at many other sites in the layers of volcanic rocks. To protect and promote the wonders of this ancient forest, the Greek state declared the area a Protected Natural Monument in 1985 (Presidential Decree 443 /1985). It has also been included in regions protected by the Barcelona Convention (Protection of the Mediterranean Sea against Pollution, OG235/A/1978).

The area of the Petrified Forest is also part of the European “Natura 2000” network (GR. 41100003).

The Lesvos Petrified Forest constitutes a fossilized forest ecosystem. It flourished in the Aegis region during the Burdigalian Period, in the Lower Miocene, approximately 18.5 million years ago. This forest was a mixed sub-tropical forest with a wide variety of vegetation, mainly conifers and fruit-bearing trees, which formed consecutive vegetation zones according to the morphology of the landscape.

During the Miocene, the whole area of the Aegean was a continental land with intense calc-alkaline volcanic activity that formed a series of volcanoes due to the subduction of the African tectonic plate under the Eurasian tectonic plate.

When the products of the volcanic eruptions blanketed the plants of the forest, all the plant organs were covered and fossilized in turn. Thus today, throughout the region, one can find fossilized branches and twigs, fruits, root systems and pieces of tree roots, as well as impressive fossils and imprints of leaves and animals living within or around the forest. The anatomical characteristics of the plants, such as the growth rings visible in cross-sections, the external part of the trunk, and the internal wood structure, are well preserved in all the fossils. The fossilized flora of the Petrified Forest includes large numbers of conifer and angiosperm (fruit-bearing) plants, with a smaller showing of pteridophytes. The fossilized trees include the highest standing fossilized tree in the world, with a height of 7.20 meters and a circumference of 8.58 meters. Trees in the petrified forest of Lesvos reach circumferences of 15 meters.

Nowadays the volcanic landscape of Lesvos Island presents a unique tomography of the crust, showing the complete sequence of the volcanic structures such as laccoliths, veins, necks, domes, cones and calderas, lava and pyroclastic flows, etc.

Thousands of visitors and students visit the area annually in order to admire and study the petrified forest through organized visits, to participate in special events and educational programs, and to see temporary exhibitions and activities. Additionally, the distinct geographical location of Lesvos island, in the vicinity of the Asian coast, contributes to the rich biodiversity of the area, as it is a meeting place of the European and Asian flora and fauna, where several Asiatic species reach their western limits of expansion.

The vegetation of the area consists of phrygana (dominant species are Sarcopoterium spinosum, Centaurea spinosa, and Ballota acetabulosa) and forests of Pinus brutia, Pinus pallasiana ssp. nigra and Quercus macrolepis. In the west part of Lesvos there are riparian plant communities, along stream banks, with Rhododendron luteum accompanied by Osmunda regalis, Nerium oleander, Pteridium aquilinum, Juncus sp. and Platanus orientalis.

The presence of Rhododendron galleries dominated by Rhododendron luteum Sweet as dominant species is considered very important for both Greece and Europe. Ruta montana L.: Very rare plant of the Greek flora. Osmunda regalis L.: This calcifuge fern is quite common in W. Europe but very rare in Greece. Pancratium maritimum L.: This used to be a common species of sandy shores but its populations are gradually decreasing. Haplophyllum megalanthum: Recently reported (1993) by Hansen and Nielsen as new for Greece. A very rare endemic East Mediterranean species. Anthemis cretica ssp. cretica is a Balkan endemic (it currently includes the species A. panachaica and A. meteorica which are included in the IUCN list of threatened plants as rare and are protected under Greek Law - Presidential Decree 67/81). All the orchid species listed under “other important species” are protected by the CITES Convention.

The first references to the fossils of Lesvos can be found in Theophrastus’ works. Theophrastus of Eressos, who was born was born circa 371 BC in the area of the Petrified Forest of Lesvos, was one of the greatest thinkers, scientists and philosophers of antiquity and the first scientist to consider fossils, to which he devoted special attention. A charismatic, observant and systematic genius, he is unquestionably considered the founder of many branches of science, such as botany, ecology and mineralogy. Diogenes Laertius refers to an index of approximately 240 works attributed to Theophrastus. The topics of these works are drawn from many areas of cognition, metaphysics, logic, ethics, politics, rhetoric, poetry and the natural sciences.

Later, the first scientific references to the Petrified Forest were made by the Austrian botanist Franz Unger (1800-1870), who made the forest known to the scientific community. Unger described the fossilized trunks in his books on the Past World (1841-1847) and in articles describing his trip to Greece (1862). Unger’s publications inspired large numbers of researchers to visit Lesvos and the Petrified Forest in the 19th century to study the natural monument.

Justification de la Valeur Universelle Exceptionelle

Many features attest to the uniqueness and the Outstanding Universal Value of the Petrified Forest: the autochthonous nature of the forest, since the trees were fossilized in their original places of growth, the large number and variety of species which make up the composition of the fossilized flora with over 46 genera and species of plants identified, the perfect preservation of plant features including the interior structures of the fossilized trees which make their identification possible, the rare finds of the fauna that lived in this ancient forest, and the composition of the petrified flora, which is one of the most important indicators of the climate conditions that once existed during the period in which the Petrified Forest was created.

Finally, this special place inspired Aristotle and Theophrastus to write masterpieces of scientific literature, which were for many centuries the basic texts on ecology, biology, geology and mineralogy.

Criterion (vi): The Lesvos Petrified Forest is closely connected with two of the most important philosophers of antiquity, Aristotle and Theophrastus. After Plato’s death in 347 BC, Aristotle went to the island of Lesvos where he was captivated by the wildlife. He studied the animal life in and around the lagoon, while his friend, Theophrastus, worked on the plants. This activity led to the birth of a new science – biology. Aristotle investigated things for himself, often dissecting animals to try to understand how they worked (sometimes while they were still alive!), and his History of Animals covers over 500 species. Aristotle organised his observations into topics such as body parts, reproductive methods and breeding habits, feeding, habitat, hibernation, and migration. This was a revolutionary idea at the time.

Theophrastus was born around 371 BC in Lesvos, Greece and was a student and successor of Aristotle. He was a prolific writer on a wide variety of subjects. His works on botany greatly influenced medieval science. He also wrote on ethics, logic, biology, physics, metaphysics, mathematics, astronomy, and the like. Many fragments of his writings have survived, including: Enquiry into PlantsOn the Causes of PlantsOn Moral CharactersOn StonesOn Sensation, as well as parts of the Physics and Metaphysics. Nevertheless, the majority of his work has been lost, as Theophrastus is believed to have written around 227 works. Most of his writings are very close to Aristotle’s, although at times richer in detail, emphasizing his empiricist side.

In Theophrastus’ treatise On Stones, he goes on to classify them based on their reaction to heat, on their hardness, and on their power of attraction. He describes a great variety of stones according to their use and origins. He writes on coal and its use as a source of heat by metal-workers, on the minerals used in the fabrication of glass, on different pigments, on plaster. He traces the origins of pumice-stones to volcanoes and of pearls to shell-fish, and speaks about fossilized remains of organic life. Theophrastus was also the first person known to have made reference to pyroelectricity: the capacity of certain materials to produce voltage when heated or cooled. From his text, as well as from a later text by Pliny the Elder (Historia Naturalis, 77AD), emerged the science of mineralogy, arguably the founding science of geology.

Criterion (vii): The Lesvos Petrified Forest was created 20 million years ago due to intense volcanic activity. The creation of the Petrified Forest is closely connected to the occurrence of intense volcanism in the North Aegean during the Lower Miocene (Burdigalian). The volcanic eruptions that occurred at the volcanic centers on Lesvos can be traced in the centre of the island (Lepetymnos, Agra, Vatoussa). Volcanic ash air fall and mudflows enclosed and fossilized the mixed subtropical Miocene forest: the isolation of plant tissue from external climatic conditions, the creation of an anaerobic environment within the mud mass, and the intense hydrothermal circulation of silica-rich fluids allowed for perfect petrifaction. The organic plant material was replaced molecule by molecule by inorganic compounds, creating a petrified forest expanding across an area exceeding 150km2 throughout which fossilized trunks, roots, branches, fruits and leaves are found.

Today, thanks to the natural erosion of volcanic rock, impressive standing and downed tree trunks have come to light. Some standing trunks reach a height of 7 meters or more, while trunk diameters approach 3 meters. Downed fossilized trunks have impressive lengths and diameters. Among the finds are large numbers of leaves and fruits. Well-preserved root systems indicate that the forest is standing in its original place of growth.

Criterion (viii): The flora of the Lesvos Petrified Forest includes more than 46 different species of plants which have been found and identified in the region of western Lesvos. The identification of the genus and species of the fossilized plants is possible due to the excellent preservation of the cellular structures and characteristics of the wood. The Lesvos Petrified Forest constitutes a fossilized forest ecosystem. It flourished in the Aegis region during the Burdigalian Period, in the Lower Miocene, approximately 18.5 million years ago. This forest was a mixed sub-tropical forest with a wide variety of vegetation, mainly conifers and fruit-bearing trees, which formed consecutive vegetational zones according to the morphology of the landscape. When the products of the volcanic eruptions blanketed the plants of the forest, all the plant organs were covered and fossilized in turn. Thus today, throughout the region, one can find fossilized branches and twigs, fruits, root systems and pieces of tree roots, as well as impressive fossils and imprints of leaves. The anatomical characteristics of the plants, such as the growth rings visible in cross-sections, the external part of the trunk, and the internal wood structure, are well preserved in all the fossils. The fossilized flora of the Petrified Forest includes large numbers of conifer and angiosperm (fruit-bearing) plants, with a smaller showing of pteridophytes. The pteridophytes include the ancestral fern (Pronephrium striacum) which was found in fossil-bearing sites in the Sigri region.

The conifers of the Lesvos Petrified Forest make up the largest and most impressive class of fossil. These conifers include pines (Pinaceae), yews (Taxaceae), and cypress (Cuprassaceae). The Cupressaceae are now widely regarded as including the Taxodiaceae, once a separate family, which includes species such as Cunninghamia and ancestral sequoias of which the Lesvos Petrified Forest has produced enormous fossils. The angiosperms include many plant families. The commonest ones in the Petrified Forest are laurels (Lauraceae) and beech (Fagaceae), which belong to the dicotyledons. Many types of laurel and cinnamon belong to the laurel family, while species of oak, chestnut and beech belong to the beech family. The Ebenaceae include the persimmon (Diospyros), the Salicaceae include poplar and willow, and the Betulaceae include birch, alder and hornbeam. Many more types of plant have been identified, such as lime, maple, blackberry, and sumac. The monocotyledon angiosperm plants are represented by many different species of palm, which dominate the lower levels of the paleolandscape.

Criterion (x): The property features important habitats resulting from ecological and geological changes over time, remnants of the Pleocene and Pleistocene evolution of the area, which are unique in Europe.

The vegetation of the area consists of phrygana (dominant species are Sarcopoterium spinosum, Centaurea spinosa and Ballota acetabulosa) and forests of Pinus brutia, Pinus pallasiana ssp. nigra and Quercus macrolepis. In the west part of Lesvos, between Chidira, Parakoilia and Agra, there are riparian plant communities, along the banks of intermittently flowing streams, with Rhododendron luteum accompanied by Osmunda regalis, Nerium oleander, Pteridium aquilinum, Juncus sp. and Platanus orientalis. The presence of Rhododendron galleries dominated by Rhododendron luteum Sweet as dominant species is considered very important for both Greece and Europe; R. luteum is a deciduous shrub which is very rare in Europe, and in Greece confined to Lesvos. Ruta montana L.: Very rare plant of the Greek flora. Osmunda regalis L.: This calcifuge fern is quite common in W. Europe but very rare in Greece. Pancratium maritimum L.: This used to be a common species of the sandy shores but its populations are gradually decreasing. Haplophyllum megalanthum: Recently reported (1993) by Hansen and Nielsen as new for Greece. A very rare endemic East Mediterranean species. Anthemis cretica ssp. cretica is a Balkan endemic (it currently includes the species A. panachaica and A. meteorica which are included on the IUCN list of threatened plants as rare and are protected under Greek Law - Presidential Decree 67/81). All the orchid species listed under “other important species” are protected by the CITES Convention.

In situ conservation within the protected area includes threatened species of aquatic and terrestrial birds, and the monk seal Monachus monachus along the coastal zone.The area is an important flyway and stopover for migratory birds, which is why it a designated EU Important Bird Area. The protected area forms a valuable laboratory for the study of plant and bird communities.

Déclarations d’authenticité et/ou d’intégrité

The property covers a total area of 15,000 ha. The Lesvos Petrified Forest maintains its authenticity as it has been preserved in its original position and the trees reveal the ecosystem living approximately twenty million years ago.

The Greek State has initiated a series of actions for the protection of the Petrified Forest of Lesvos. The first Ministerial Decision of the Culture Minister was published on 31 January 1958, designating the Petrified Forest of Lesvos a specially protected region.

The expropriation of two regions of 500 acres (at Bali Alonia and Hamandroula), containing a large number of fossilized trunks, occurred in 1965 by decision of the Minister of Agriculture.

In 1985, on the proposal of the Ministry of Agriculture, the "Petrified Forest" was declared a Protected Natural Monument (PD 443/85). Under this decree, one marine and four land sections are protected. These sections cover a large area of 150,000 acres in the regions of Sigri, Antissa and Eressos, the marine section around the islet of Nisiopi or Megalonisi, and four land regions, as well as individual appearances of fossilized trunks.

Under this law, excavation, embankment, sampling of ground and geological sublayers and other actions that could cause the deterioration and alteration of the geological shape of the landscape, as well as the cutting, collection, destruction or transport of fossils, is strictly prohibited.

In 1996 the Forest Police Provision regulated areas of the Petrified Forest declared Protected Natural Monuments.

The Natural History Museum of the Petrified Forest of Lesvos was founded by law (Law 2260/94 article 2) in 1994, its aim being the study, research, promotion, maintenance, protection, conservation, and correct use of the Petrified Forest.

The islet of Megalonisi or Nisiopi is protected as a Place of Particular Natural Beauty (Hellenic Government Gazette 1176/V/2000)

The area of the Petrified Forest is included among the regions on National List of the Natura 2000 Network, after it was included in the Western Peninsula Lesvos - Petrified Forest region (code GR 4110003).

In these regions, the maintenance of natural ecosites as well as wild fauna and flora is promoted. The network is made up of regions containing types of ecosite identified in EU directives, which should be maintained or, potentially, re-established to a satisfactory level of maintenance, priority ecosites, as well as types of flora and fauna.

An area of 340 km2 in the region has been designated an Area of Special Protection for Birds (Special Protected Area) according to the No. 4 Directive on Birds (79/409/EC). The proposed region has the code "GR134: South-western Peninsula-Petrified Forest of Lesvos" and runs along the western seashores of the island, its north-south border following the imaginary line linking the settlements of Lapsarna, Ligeri, Perivoli Monastery, Vatoussa, Revma, the heights of Mt Mitero and Parakila. The region has already been designated an Important Region for Birds (SPP).

Six sites in the region have been designated wildlife refuges by the Forestry Department of the Ministry of Environment, Energy and Climate Change.

Comparaison avec d’autres biens similaires

There is no comparison with any other similar property, such as the Lake Turkana Petrified Forest in Kenya or the Petrified Forest in Arizona USA. Both of these include lying petrified tree trunks, while in Lesvos the Petrified Forest was covered by pyroclastic material and was silicified in situ. There are hundreds of standing petrified trees with their root systems intact in an upright position, as a result of the volcanic explosions and their products covering the whole ecosystem, which has been fossilized in situ due to favorable geochemical conditions.

When the products of the volcanic eruptions blanketed the plants of the forest, all the plant organs were covered and fossilized in turn. Thus today, throughout the region, one can find fossilized branches and twigs, fruits, root systems and pieces of tree roots, as well as impressive fossils and imprints of leaves and animals living within or around the forest.