The Biržai Forest is a

old-growth forest An old-growth forest or primary forest is a forest that has developed over a long period of time without disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Natio ...

Biržai District Municipality Biržai (, also known by several #Name, alternative names) is a city in northern Lithuania. Famous for its reconstructed Biržai Castle Manor house, manor, the whole region is renowned for its many traditional-recipe beer breweries. Name The e ...

, Lithuania. The forest is recognised as a

Key Biodiversity Area Key Biodiversity Areas (KBA) are geographical regions that have been determined to be of international importance in terms of biodiversity conservation, using globally standardized criteria published by the IUCN as part of a collaboration between sc ...

of international significance, with about 99.96% of its area under

protection Protection is any measure taken to guard something against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although ...

. It is managed, with some other smaller forests, by the (Biržų miškų urėdija).

Ecology

The Biržai Forest ecosystem consists predominantly of forest habitat (98 % of the total area), with a small portion (2%) classified as artificial terrestrial habitat.The forest lies at an elevation of roughly 60 to 70 metres above sea level and covers an area of about . The Biržai Botanical Reserve was established to preserve the characteristic plant communities of the Biržai forest, which is dominated by

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...

, and

aspen Aspen is a common name for certain tree species in the Populus sect. Populus, of the ''Populus'' (poplar) genus. Species These species are called aspens: * ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') * ''Populus da ...

species. The forest includes areas characterised as Fennoscandian hemiboreal natural old broad-leaved deciduous forests rich in

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

s and Fennoscandian herb-rich forests with ''

Picea abies ''Picea abies'', the Norway spruce or European spruce, is a species of spruce native to Northern Europe, Northern, Central Europe, Central and Eastern Europe. It has branchlets that typically hang downwards, and the largest cones of any spruce, ...

'', with an average

stand Stand or The Stand may refer to: Other * To assume the upright position of standing * Forest stand, a group of trees * Area of seating in a stadium, such as bleachers * Stand (cricket), a relationship between two players * Stand (drill pipe) ...

age of about 123 years.

Paleoenvironmental history

Scientific research has revealed that the Biržai region has a rich ecological history dating back tens of thousands of years. A 1992 study reported the discovery of 13-meter thick

lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

sediments beneath a Late Valdaian moraine complex in a paleokarst depression near Biržai.

Radiocarbon dating Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotop ...

of wood fragments found in these sediments yielded dates of approximately 34,440 ± 1500 and 33,460 ± 1060 years BP (Before Present), placing them in the Middle Valdaian period.

Pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

analysis of these sediments indicated that during this period, the Biržai area supported

taiga Taiga or tayga ( ; , ), also known as boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, spruces, and larches. The taiga, or boreal forest, is the world's largest land biome. In North A ...

landscapes similar to those found today in the

Pechora Pechora (; ) is a types of inhabited localities in Russia, town in the Komi Republic, Russia, located on the Pechora (river), Pechora River, west of and near the northern Ural Mountains. The area of the town is . Population: History Pechor ...

basin and eastern

Ural Mountains The Ural Mountains ( ),; , ; , or simply the Urals, are a mountain range in Eurasia that runs north–south mostly through Russia, from the coast of the Arctic Ocean to the river Ural (river), Ural and northwestern Kazakhstan.

. The dominant vegetation consisted of conifer forests with

(''Pinus''),

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

(''Picea''), and

larch Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to the cooler regions of the northern hemisphere, where they are found in lowland forests in the high la ...

(''Larix''), with some

(''Betula'') and

alder Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...

(''Alnus'') present during certain stages. The herbaceous layer included grasses (

Poaceae Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivate ...

), sedges (

Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...

), and various other plants including '' Artemisia'' and

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

s. The research concluded that no

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice s ...

was present in the Baltic Region during this Middle Valdaian interval, confirming that the Biržai area has experienced significant ecological changes throughout the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

period.

Biodiversity

Biržai Forest hosts diverse beetle communities associated with dead wood. Research has shown that the forest's protected status and abundance of dead wood provide important habitats for saproxylic beetles (beetles dependent on dead and decaying wood). The Biržai Botanical Reserve was one of four protected areas in Lithuania studied for beetle diversity, with research confirming the importance of dead wood from different tree species in maintaining beetle

diversity Diversity, diversify, or diverse may refer to: Business *Diversity (business), the inclusion of people of different identities (ethnicity, gender, age) in the workforce *Diversity marketing, marketing communication targeting diverse customers * ...

. The forest contains

old-growth An old-growth forest or primary forest is a forest that has developed over a long period of time without Disturbance (ecology), disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organizati ...

stands where natural processes, including windfall and natural tree decay, create ideal conditions for these specialised beetle communities.

Conservation status

The Biržai Forest was formally assessed and confirmed as a

in 2004. It is classified as a Regional KBA and was originally designated as an Important Bird and Biodiversity Area. The site's international significance is based on previously established criteria and thresholds for the identification of Important Bird and Biodiversity Areas, though available data indicate that it does not meet global KBA criteria and thresholds set out in the Global Standard.

References

{{reflist, refs= {{cite web , title=Dabartis , publisher=Biržų miškų urėdija (Biržai Forestry Authority) , year=2007 , url=http://www.birzu-miskai.lt/?id=8 , archive-url=https://web.archive.org/web/20080302202555/http://www.birzu-miskai.lt/?id=8 , archive-date=2 March 2008 {{cite journal , last1=Gaigalas , first1=Algirdas , last2=Serebryanny , first2=Leonid , last3=Valueva , first3=Maisa , title=Middle Valdaian forest environments at Biržai, northern Lithuania , journal=Boreas , volume=21 , issue=3 , pages=289–293 , year=1992 , doi=10.1111/j.1502-3885.1992.tb00033.x , bibcode=1992Borea..21..289G , issn=0300-9483 Key Biodiversity Areas Partnership (2025) Key Biodiversity Areas factsheet: Birzai forest. Extracted from the World Database of Key Biodiversity Areas. Developed by the Key Biodiversity Areas Partnership. Downloaded from https://keybiodiversityareas.org/ on Apr 10, 2025. {{cite journal , last1=Lekoveckaitė , first1=Aistė , last2=Jimenez , first2=Maria Fernanda Torres , last3=Trakimas , first3=Giedrius , last4=Ferenca , first4=Romas , last5=Podėnienė , first5=Virginija , title=Tree species affect beetle diversity on the common deciduous dead wood in Lithuanian unmanaged forests , journal=Forests , volume=14 , issue=9 , year=2023 , doi=10.3390/f14091836 , doi-access=free , page=1836, bibcode=2023Fore...14.1836L Forests of Lithuania Biržai District Municipality Old-growth forests

Ecology

Paleoenvironmental history

Biodiversity

Conservation status

See also

References