In
paleoclimatologyPaleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rocks to determine the past state of the climate system on Earth....
of the
HoloceneThe Holocene is a geological epoch which began approximately 11 700 years ago . According to traditional geological thinking, the Holocene continues to the present. The Holocene is part of the Neogene and Quaternary periods. Its name comes from the Greek words and , meaning "entirely...
, the
Boreal was the first of the
Blytt-SernanderThe Blytt-Sernander classification, or sequence, is a series of north European climatic periods or phases based on the study of Danish peat bogs by Axel Blytt and Rutger Sernander...
sequence of north European climatic phases that were originally based on the study of Danish peat bogs, named for Axel Blytt and Rutger Sernander, who first established the sequence. In peat bog sediments, the Boreal is also recognized by its characteristic
pollen zonePollen zones are a system of subdividing the last glacial period and Holocene paleoclimate using the data from pollen cores. The sequence provides a global chronological structure to a wide variety of scientists, such as geologists, climatologisists, geographists and archaeologists, who study the...
. It was preceded by the
Younger DryasThe Younger Dryas stadial, named after the alpine/tundra wildflower Dryas octopetala, and also referred to as the Big Freeze, was a geologically brief cold climate period following the Bølling/Allerød interstadial at the end of the Pleistocene between approximately 12,800 to 11,500 years ago, and...
, the last cold snap of the
PleistoceneThe Pleistocene is the epoch from 2.588 million to 12 000 years BP covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, and followed by the
AtlanticThe Atlantic in palaeoclimatology was the warmest and moistest Blytt-Sernander period, pollen zone and chronozone of Holocene north Europe. The climate was generally warmer than today. It was preceded by the Boreal, with a climate similar to today’s, and was followed by the Sub-Boreal, a transition...
, a warmer and moister period than our most recent climate. The Boreal, transitional between the two periods, varied a great deal, at times comprising within it climates like today's.
Subdividing the Boreal
Subsequent to the original Blytt-Sernander scheme, the first stage of the Boreal was divided off as a
Pre-boreal transitional phase, followed by the Boreal proper. Some current schemes based on pollen zones also distinguish a pre-Boreal (pollen zone IV), an early Boreal (pollen zone V) and a late Boreal (pollen zone VIa, b, and c).
Dating
The generally accepted date for the end of the
Younger DryasThe Younger Dryas stadial, named after the alpine/tundra wildflower Dryas octopetala, and also referred to as the Big Freeze, was a geologically brief cold climate period following the Bølling/Allerød interstadial at the end of the Pleistocene between approximately 12,800 to 11,500 years ago, and...
and the start of the Pre-Boreal is 11,500
Before PresentBefore Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use 1 January 1950 as the arbitrary origin of the age scale...
calibrated. The start of the period is relatively sharply defined by a rise of 7 °C in 50 years. The date is based fairly solidly on
GreenlandGreenland is an autonomous constituent country within the Kingdom of Denmark located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago...
ice coreAn ice core is a core sample from the accumulation of snow and ice over many years that have re-crystallized and have trapped air bubbles from previous time periods...
s, which give 11,640 BP for the late Younger Dryas and 11,400 BP for the early Pre-Boreal.
But estimates of other dates vary by up to 1000 years, for a number of reasons. First, "Boreal" can identify a paleoclimate, a pollen zone or a temporally-fixed chronozone, and those three bases of definition allow quite different dates. Second, different dating methods obtain different dates. The underlying problem is that climate and pollen vary somewhat from region to region. The scientists of each region use the methods available in their region, whether lake varves, the annual layers of sediment from ancient or modern lake bottoms, ice cores or counts of tree rings (
dendrochronologyDendrochronology or tree-ring dating is the scientific method of dating based on the analysis of patterns of tree-rings. Dendrochronology can date the time at which tree rings were formed, in many types of wood, to the exact calendar year...
).
Standardization has become of increasing concern to scientists everywhere. Dates from many methods continue to multiply as paleoclimatologists seek higher resolution. But it is unclear whether regional variation will allow high-resolution standardization.
Yet, there are some solid dates of the PreBoreal and Boreal. The
Saksunarvatn tephraIn the new science of tephrochronology, Saksunarvatn tephra are volcanic ejecta that form an ash layer that is useful in dating Northern European sediment layers that were laid down during the Boreal period, the warm climate phase that followed the cold snap of the Younger Dryas as the earth made...
(an ash layer of volcanic fall-out), is dated in Greenland ice to 10,180±60 BP; in lake deposits at Krakenes in Norway, to 10,010–9,980 years BP calibrated; in northwest German lakes, to 10,090 BP calibrated. The tephra occurs in early Boreal contexts. So, it seems certain that the early Boreal (pollen zone V) includes the year 10,000 BP. Similarly, the late Boreal includes the Kilian/Vasset tephra of Swiss and southwest German lakes at 8200 BP, all calibrated. But the borders are less certain.
Studies of
bogA bog or mire is a wetland type that accumulates acidic peat, a deposit of dead plant material—usually mosses, but also lichens in Arctic climates....
s in northwest
RussiaRussia , officially known as both Russia and the Russian Federation , is a country in northern Eurasia . It is a semi-presidential republic, comprising 83 federal subjects...
are the basis for a division of the PreBoreal (PB) into PB-1, 10,000-9800, and PB-2, 9800–9300 BP incal. The scheme goes on to divide the Boreal (BO) into BO-1, 9300–9000, BO-2, 9000–8500, and BO-3, 8500–8000, incal.
CalPal used on these dates suggests overall boundaries of 11,500 and 10,500 BP for the Pre-Boreal, and the end of the Boreal at 8900.
Dates given recently are usually earlier than those given more than 10 years ago. For example, Iverson (1973) and Rud (1979) give dates of 10,000–9000 BP for the PreBoreal and 9000–8000 BP for the Boreal, which are incalibrated C-14 dates based on Scandinavian pollen stratigraphy.
Presumably, more-recent dates are more accurate, as technology improves with time, often quite rapidly. Yet, pollen and climate phases also to some degree may depend on latitude, so no date can be regarded as certainly wrong. Scientists look for the overall pattern of the dates, but that technique is not 100% reliable, either.
Description
Before the Pre-Boreal,
EurasiaEurasia is a large landmass covering about 52,990,000 km
2 or about 10.6% of the Earth's surface...
was locked in the chill of the Younger Dryas and was a mostly continuous
tundraIn physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes from Kildin Sami tūndâr, which means "uplands, treeless mountain tract." There are two types of tundra: Arctic tundra and alpine tundra...
belt, with regions of
taigaTaiga is a biome characterized by coniferous forests. Covering most of inland Alaska, Canada, Sweden, Finland, inland Norway, Highland Scotland and Russia , as well as parts of the extreme northern continental United States , northern...
, covered with a blanket of grasses, shrubs and other low plants typical of open land. Large numbers of
herbivoreA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
s wandered in herds over vast distances. The blanket teemed with small, rapidly reproducing species, which supported food chains of larger predators. The largest predators and humans hunted the mammals of the open tundra.
The Pre-Boreal began with a sudden rise in temperature that abruptly changed this ecosystem. Forest replaced the open lands in Europe, and forest-dwelling animals spread from southern
refugiaIn biology a refugium is a location of an isolated or relict population of a once widespread species.This isolation can be due to climatic changes or human activities such as deforestation and over-hunting...
and replaced the ice-age tundra mammals; new climax ecosystems developed. The old fauna persisted in Central Asia, but were soon hunted out, as they were not replenished by the larger areas formerly nourishing the ecosystem.
The sea brought additional isolation by rising rapidly and drowning the entire coast. Ireland was cut off early in the Boreal, suffering an impoverishment of species. It is home to only two-thirds of the species present in Britain. Britain was cut off by the end of the Boreal. Forest had closed over the former European tundra.
Humans had to adapt to the encroaching forest or move east with the large mammals. Those who stayed became hunter-gatherers of the forests and fishers of the numerous bays, inlets and shallow waters around the thousands of islands that now spangled the seas of Europe. They lived richly and were encouraged to enter the pre-productive phase that we call the
MesolithicThe Mesolithic or "Middle Stone Age" was a period in the development of human technology in between the Paleolithic or Old Stone Age and the Neolithic or New Stone Age. The term was introduced by John Lubbock in his work Pre-historic Times, published in 1865. The term was, however, not much used...
. Those who moved east hunted out the last of wild big game and turned their best efforts into learning to herd what was left. In the Americas, humans had left the Paleoindian phase and were now in the Archaic.
Meanwhile humanity toward the south of the north temperate zone had already turned to food production in a number of widely separated locations and were on the brink of civilization. There is no evidence of any extensive contact with the cultures of the north during the Boreal. The producers tended to live in dense centers without any interest in moving from there except when motivated to find new lands. The gatherers ranged widely over their lands, building only temporary settlements in which to spend the winter.
Flora
During the Pre-Boreal pollen zone IV, large quantities of tree pollen began to replace the pollen of open-land species, as the most mobile and flexible arboreal species colonized their way northward, replacing the ice-age tundra plants. Foremost among them were the
birchBirch is the name of any tree of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae.-Description:...
es,
Betula pubescens and
Betula pendula, accompanied by
Sorbus aucupariaSorbus aucuparia , is a species of the genus Sorbus , native to most of Europe except for the far south, and northern Asia...
and Quaking Aspen,
Populus tremulaAspen is a common name for trees of the Salicaceae family, most of those in a section, Populus sect. Populus, of the Populus genus. Some of the species in the section are:...
. Especially sensitive to temperature changes and moving northward almost immediately were
Juniperus nana and
J. communis, the dwarf and shrub
JuniperJunipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
respectively, which reached a maximum density in the Pre-Boreal, before their niches were shaded out.
PinePines are coniferous trees in the genus Pinus , in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Distribution:...
soon followed, for which reason the resulting open woodland is often called a birch or a pine-birch forest.
In the yet warmer early Boreal pollen zone V,
Corylus avellana (
hazelThe hazels are a genus of deciduous trees and large shrubs native to the temperate northern hemisphere. The genus is usually placed in the birch family Betulaceae, though some botanists split the hazels into a separate family Corylaceae.They have simple, rounded leaves with double-serrate margins...
) and pine expanded into the birch woodlands to such a degree that
palynologistsPalynology is the science that studies contemporary and fossil palynomorphs, including pollen, spores, orbicules, dinoflagellate cysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter and kerogen found in sedimentary rocks and sediments...
refer to the resulting ecology as the hazel-pine forest. In the late Boreal it was supplanted by the spread of a deciduous forest called the mixed-oak forest. Pine, birch and hazel were reduced in favor of
Quercus,
Ulmus,
TiliaTilia is a genus of about 30 species of trees, native throughout most of the temperate Northern Hemisphere, in Asia , Europe and eastern North America; it is not native to western North America...
and
Alnus. The former tundra was now closed by a canopy of dense forest. In the marshland
Typha latifoliaTypha latifolia is a perennial herbaceous plant in the genus Typha, which grows in temperate, subtropical and tropical areas throughout the Northern Hemisphere...
prevailed. Less cold-tolerant species such as
ivyHedera is a genus of 15 species of climbing or ground-creeping evergreen woody plants in the family Araliaceae, native to the Atlantic Islands, western, central and southern Europe, northwestern Africa and across central-southern Asia east to Japan...
and
mistletoeMistletoe is the common name for a group of hemi-parasitic plants in the order Santalales that grow attached to and within the branches of a tree or shrub...
were to be found in
DenmarkDenmark is a Scandinavian country in Northern Europe and the senior member of the Kingdom of Denmark. It is the southernmost of the Nordic countries; southwest of Sweden and south of Norway, and it is bordered to the south by Germany. Denmark borders both the Baltic and the North Sea...
.
Fauna
The new forest was populated with animals from
refugiaIn biology a refugium is a location of an isolated or relict population of a once widespread species.This isolation can be due to climatic changes or human activities such as deforestation and over-hunting...
in Italy, Spain and the Balkans. Animals such as
Emys orbicularis (European pond tortoise), which require warmer temperatures, were to be found in
DenmarkDenmark is a Scandinavian country in Northern Europe and the senior member of the Kingdom of Denmark. It is the southernmost of the Nordic countries; southwest of Sweden and south of Norway, and it is bordered to the south by Germany. Denmark borders both the Baltic and the North Sea...
. The
Eurasian golden ploverThe Eurasian Golden Plover, Pluvialis apricaria, is a largish plover. This species is similar to two other golden plovers. American Golden Plover, Pluvialis dominiica, and Pacific Golden Plover, Pluvialis fulva, are both smaller, slimmer and relatively longer-legged than Eurasian Golden Plover,...
came as far north as
NorwayNorway , officially the Kingdom of Norway, is a country in Northern Europe occupying the western portion of the Scandinavian Peninsula, as well as Jan Mayen and the Arctic archipelago of Svalbard under the Spitsbergen Treaty...
.
The plains
PerissodactylaThe odd-toed ungulates are browsing and grazing mammals such as horses, tapirs and rhinoceroses whose hooves each feature an odd number of toes. The middle toe on each hoof is also usually larger than its neighbors...
(horses, rhinoceros, etc.) were replaced by forest Cervidae:
Cervus elaphus (
red deerThe Red Deer is one of the largest deer species. The Red Deer inhabits most of Europe, the Caucasus Mountains region, Asia Minor and parts of western and central Asia. It also inhabits the Atlas Mountains region between Morocco and Tunisia in northwestern Africa, being the only species of deer to...
),
Capreolus capreolus (
roe deerThe European Roe Deer is a deer species of Europe, Asia Minor, and Caspian coastal regions. There is a separate species known as the Siberian Roe Deer that is found from the Ural Mountains to as far east as China and Siberia...
) and
Alces alces (
elkThe moose or common elk , , is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a "twig-like" configuration....
).
Sus scrofaWild boar is a species of pig, including at least 16 subspecies, and part of the biological family Suidae. It is the wild ancestor of the domestic pig, an animal with which it freely hybridises. Wild boar are native across much of Central Europe, the Mediterranean Region and much of Asia as far...
(wild pig) rooted around in the oaks, while
Bos primigenius (
aurochsThe aurochs or urus was a type of wild cattle, the ancestor of domestic cattle. It inhabited Europe, Asia and North Africa, but is now extinct; it survived in Europe until 1627....
) haunted the glades and thickets, creating a state of awed unease for human travellers. The forest had its share of predators:
Canis lupus (wolf),
Ursus arctos (
brown bearThe brown bear is a large bear distributed across much of northern Eurasia and North America. It weighs 100 to 680 kilograms and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family, and as the largest land based predator.While the brown...
),
Lynx lynx (
lynxA lynx is any of four big-sized wild cats. All are members of the genus Lynx, but there is considerable confusion about the best way to classify felids at present, and some authorities classify them as part of the genus Felis...
),
Felis sylvestrisThe Wildcat , sometimes Wild Cat or Wild-cat, is a small felid native to Europe, the western part of Asia, and Africa. It is a hunter of small mammals, birds, and other creatures of a similar size. There are several subspecies distributed in different regions...
(wildcat).
Lepus europaeus (
hareHares and jackrabbits are leporidaes belonging to the genus Lepus. Hares less than one year old are called leverets.Hares are very fast-moving...
) provided a tasty meal for any who could catch them.
The inland waters were as today's European waters would be if they were left alone.
Castor fiber (
beaverThe beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, Castor canadensis and Castor fiber . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
) increased the wetlands by damming the streams and ponds.
Lutra lutra (
otterOtters are semi-aquatic fish-eating mammals. The otter subfamily Lutrinae forms part of the family Mustelidae, which also includes weasels, polecats, badgers, as well as others. With thirteen species in seven genera, otters have an almost worldwide distribution...
) hunted for fish there. Such fish as
Esox lucius (
northern pikeThe northern pike , Esox lucius, is a species of carnivorous fish of the genus Esox...
) and
Siluris glanis (
catfishCatfish are a diverse group of hairey fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest, the Mekong giant catfish from Southeast Asia and the longest, the wels catfish of Eurasia, to detritivores , and even to a tiny...
) could be found in inexhaustible abundance. The continuous Boreal forests must surely have been the wonderful and frightening wilderness remembered in legend.
Humans
The Preboreal-Boreal in Europe was a time of transition from the Palaeolithic cultures to the
MesolithicThe Mesolithic or "Middle Stone Age" was a period in the development of human technology in between the Paleolithic or Old Stone Age and the Neolithic or New Stone Age. The term was introduced by John Lubbock in his work Pre-historic Times, published in 1865. The term was, however, not much used...
. Forests and drowned coastlands were places of plenty. Human settlements avoided the deep forest in favor of
streamA stream is a flowing body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, kill, lick, rill, river syke, bayou, rivulet, or run...
s,
lakeA lake is a terrain feature , a body of liquid on the surface of a world that is localized to the bottom of basin and moves slowly if it moves at all. Another definition is, a body of fresh or salt water of considerable size that is surrounded by land...
s, and especially
bayA bay is an area of water mostly surrounded or otherwise demarcated by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds....
s of the
oceanAn ocean is a large body of saline water, and a principal component of the hydrosphere. Approximately 75% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
.
Pre-Boreal settlements have been found in north-central Europe, such as at
FriesackFriesack is a town in the Havelland district, in Brandenburg, Germany. It is situated 22 km northeast of Rathenow, and 25 km southwest of Neuruppin. It is known for its Mesolithic archaeological site....
. There an unusual find of net fragments made from plant fibers suggested that fishing was an important part of life.
Finds from another settlement at
Vis- Geography :* Vis , a Croatian island in the Adriatic sea* Vis , town and municipality on the island of Vis* Vis, Bulgaria, a village in Ivaylovgrad municipality, Haskovo Province, Bulgaria* Vis , in south-central France- Initialisms :...
, near the
Vychegda RiverVychegda is a river in the European part of Russia, tributary to the Northern Dvina. Its length is about 1,100 km. Its source is approx. 310km west of the northern Ural Mountains. It flows roughly in western direction, through Komi Republic and Arkhangelsk Oblast. The largest city along the...
in
RussiaRussia , officially known as both Russia and the Russian Federation , is a country in northern Eurasia . It is a semi-presidential republic, comprising 83 federal subjects...
, offer more details of life in a settlement of the Boreal. Plant fibers were used for
basketA basket is a container which is traditionally constructed from stiff fibres, often made of willow. . The top is either left open or the basket may be fitted with a lid....
s and for hafting bone points to shafts. Fishermen crossed the waters in bark boats plied by
oarAn oar is an implement used for water-borne propulsion. Oars have a flat blade at one end. The oarsmen grasp the oar at the other end. What distinguishes oars from paddles is that paddles are held by the paddler, and are not connected with the vessel. Oars generally are connected to the vessel by...
s, and set nets. They also made hand-held nets from wooden hoops and plant fiber.
Food gathering continued in winter:
skiA ski is a long, flat device worn on the feet designed to help the wearer slide smoothly over snow. Originally intended as an aid to travel in snowy regions, they are now primarily used for recreational and sporting purposes...
s and sledge runners have been found.
ReindeerThe reindeer , also known as the caribou when wild in North America, is an Arctic and Subarctic-dwelling deer, widespread and numerous across the Arctic and Subarctic.- Distribution and habitat :...
continued to be hunted and probably herded. Bows, arrows, and spears have been found. Implements were likely to be embellished by sculpting in wood or bone. Only a few motifs were used: the elk's head, the snake, and human.
In Europe, the major culture was the Maglemosian (9000–6400 BC), extending into
DenmarkDenmark is a Scandinavian country in Northern Europe and the senior member of the Kingdom of Denmark. It is the southernmost of the Nordic countries; southwest of Sweden and south of Norway, and it is bordered to the south by Germany. Denmark borders both the Baltic and the North Sea...
and Russia. Localized cultures included the Nieman of
LithuaniaLithuania , officially the Republic of Lithuania is a country in Northern Europe, the southernmost of the three Baltic states. Situated along the southeastern shore of the Baltic Sea, it shares borders with Latvia to the north, Belarus to the southeast, Poland, and the Russian exclave of...
, the
KundaEstonia was settled near the end of the last glacial era, beginning from around 8500 BC. Before the German invasions in the 13th century proto-Estonians of the Ancient Estonia worshipped the spirits of nature...
of
LatviaLatvia , officially the Republic of Latvia is a country in the Baltic region of Northern Europe. It is bordered to the north by Estonia , to the south by Lithuania , to the east by the Russian Federation , and to the southeast by Belarus . Across the Baltic Sea to the west lies Sweden...
and
EstoniaEstonia , officially the Republic of Estonia , is a country in Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by the Russian Federation...
, the
AzilianThe Azilian is a name given by archaeologists to an industry of the Epipaleolithic in northern Spain and southern France.It probably dates to the period of the Allerød Oscillation around 10,000 years ago and followed the Magdalenian culture...
of
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
, and the Epi-Gravettian of
ItalyItaly , officially the Italian Republic , is a country located on the Italian Peninsula in Southern Europe and on the two largest islands in the Mediterranean Sea, Sicily and Sardinia. Italy shares its northern, Alpine boundary with France, Switzerland, Austria and Slovenia...
. Towards the end of the Mesolithic, local traditions began to multiply, perhaps due to influences from the south, or due to the general advance of culture.
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