Western European broadleaf forests
Western European broadleaf forests are a vital ecological component of central-western Europe, spanning regions primarily in the midmountain ranges of countries such as France, Switzerland, Germany, Austria, and the Czech Republic. Characterized by a temperate deciduous climate, these forests experience moderate temperatures, with annual averages around 55°F (13°C), and ample rainfall ranging from 39 to 71 inches (1,000 to 1,800 millimeters). The forest's distinctive composition includes prominent tree species such as sessile oak, pedunculate oak, hornbeam, and beech, thriving in diverse microclimates from 2,300 to 4,000 feet (700 to 1,200 meters) above sea level.
The understory of these forests hosts a rich array of plant species, contributing to their biodiversity. However, many large mammal and bird populations within these forests are in decline, with various species, including the European bison and lynx, facing significant threats due to habitat loss and fragmentation. Historically, the forests have been utilized for their durable hardwoods in construction and shipbuilding, while also holding cultural significance across various European societies.
Despite their ecological importance, climate change poses a significant threat to these forests, leading to potential habitat shifts, increased invasions of non-native species, and more frequent droughts. This delicate balance between human use and conservation continues to shape the future of Western European broadleaf forests.
Western European broadleaf forests
- Category: Forest Biomes.
- Geographic Location: Europe.
- Summary: These characteristic temperate deciduous forests are a vital, living piece of the European habitat puzzle.
Western European broadleaf forests represent a group of temperate forest communities that cover a large area of central-western Europe, mainly in the midmountain ranges of (from west to east) France (Central Massif), Switzerland (Jura Mountains), Germany (Central German Uplands), Austria (Bohemian Massif), and the Czech Republic. Their eastern limits reach approximately to the Caucasian and Baltic mountains and Asia Minor territories.
In these areas, the general climate is Euro-Siberian, characterized by moderate temperatures (average annual temperature of 55 degrees F or 13 degrees C), with cool summers and relatively mild winters, except in certain eastern areas, where very cold winters occur. Most areas present a uniform annual rainfall regime without water-scarcity problems for forest communities. This regime averages 39–71 inches (1,000–1,800 millimeters) annually. In areas influenced by closer mediterranean conditions, a slight summer drought can be present.
Forest Composition
The Western European Broadleaf Forests biome is represented by three main communities: deciduous oak, including sessile oak and pedunculate oak; hornbeam, including common hornbeam and hop-hornbeam; and beech.
Stands of sessile oak (Quercus petraea) and pedunculate oak (Quercus robur) are spread across the basal areas of central-western Europe's mid-mountain ranges, mainly from 2,300–3,300 feet (700–1,000 meters) above sea level, and influenced by Euro-Siberian bioclimatic conditions. Although their distribution ranges are similar, these two deciduous oaks present slight differences. Sessile oaks are not lobed and have a longer stalk, up to 3 to 4 inches (80–100 millimeters). The oaks also produce different fruits. Quercus robur acorns have a long peduncle; Quercus petraea acorns don't have it or have a very short one. As to habitat, pedunculate oak manifests more resistance to continental conditions and shows a major expansion over central eastern Europe to the Urals.
Community composition comprises a dense understory, composed of a diverse group of taxa characteristic of wet-temperate conditions, such as wood sage (Teucrium scorodonia), purple betony (Stachys officinalis), spurge-laurel (Daphnelaureola), and sanicle (Sanicula europaea). There are also some shrubs that provide edible fruits, such as blackthorn (Prunus spinosa) and wild strawberries (Fragaria vesca); and ferns like Pteridium aquilinum and Blechnum spicant.
Otherwise, these deciduous oak lands are enriched with other companion trees such as common hawthorn (Crataegus monogyna)—sometimes in shrub form—as well as holly (Ilex aquifolium), whitebeam (Sorbus aria), and shepherd whitebeam (Sorbus torminalis). When deciduous oak lands become altered, the forest community tends to be replaced by heathlands that are composed mainly of secondary succession species like heathers and brooms.
Hornbeams
Common hornbeam (Carpinus betulus) and hop-hornbeam (Ostrya carpinifolia) stands usually occur in intermediate zones between deciduous oak lands and beech forests, located at 2,300–4,000 feet (700–1,200 meters), and mainly in shady and humid soils of the central Europe mid-mountain areas. A few relict populations of these species are present on the islands of Corsica, Sardinia, and Sicily.
Morphological differences between these two species of the Betulacea family are manifested mainly in bark, fruits, and leaves. Whereas common hornbeam has a greenish-gray bark, even in older trees, hop-hornbeam has a grayish color that becomes darker with time. Also, common hornbeam forms seed brunches composed of involucres divided into three segments that partially surround one small nut, whereas hop-hornbeam forms seed bunches in which each seed contains two to four small nuts. Hop-hornbeam leaves have lateral nerves ramified to the edge.
Community composition includes an usually rich and dense understory, with wet-temperate shrubs like common dogwood (Cornus sanguinea), European cornel (Cornus mas), and butcher's broom (Ruscus aculeatus); and perennial herbs like black hellebore (Helleborus niger) or different cyclamen species. Also, the formation of mixed stands is very usual, as common hornbeam and hop-hornbeam are accompanied by other tree species, mainly deciduous oaks and beech, but also by common hazel (Corylus avellana) and South European flowering ash (Fraxinus ornus).
Fauna
The region is home to a variety of animal and bird species, but most large mammal populations are in decline, with 20–25 percent of mammals and 15–40 percent of forest birds listed as threatened in central Europe. The population of European bison (Bison bonasus) was down to 12 animals when it was rescued from extinction. In 2021, more than six thousand bison lived in the wild. The lynx (Lynx lynx) is endangered because it needs a large home range in a remote habitat. Other threatened mammals include the wolf (Canis lupus), steppe polecat (Mustela eversmannii), and spotted souslik (Spermophilus suslicus).
Two eagles of the region, the white-tailed eagle (Haliaeetus albicilla) and the greater spotted eagle (Aquila clanga), need large tracts of undisturbed forests, lakes, or rivers, and often wetlands to thrive. They are threatened by the loss of unfragmented habitats, and by poaching along their migration routes in the southeastern part of Europe. Other threatened birds include the corncrake (Crex crex), lesser kestrel (Falco naumanni), and aquatic warbler (Acrocephalus paludicola).
Human Use of Forests
Historically, due to their hardness, deciduous oaks have been used in the construction of houses, traditional shipbuilding, and in railway industries. This is especially true of sessile oak, which has a straight growth compared to pedunculate oak. Sessile oak wood also is greatly appreciated in the wine industry, due to the organoleptic qualities that the barrels provide to wine. Also, oak wood is used for firewood and charcoal.
At the same time, oak is an important symbolic tree for various European cultures, representing values such as strength and commitment. Greeks associated it with Zeus; Romans did the same with the god Jupiter. Germanic tribes worshiped the great god oak, while Gauls chose oak forests as cult places (in fact, druid means oak man).
Hop and common hornbeam wood also have been used in construction, as well as in traditional medicine. Hornbeam leaves are boiled to obtain eye drops, and the boiled bark is a well-known cough remedy.
Climate change further threatens the biodiversity of these forests. Warming temperatures, which are projected for the region, will tend to impose habitat shifts, generally moving some species to higher, cooler elevations—as well as foment some expansion of habitat for invasive species and pests. On the other hand, the warmer climate would tend to boost the production of some of the most desirable commodity trees here. Trending against this is the increased likelihood of more frequent and more severe drought events.
Bibliography
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