Is located between the 36°00´ latitude south and 71° 00’latitude west until the pacific Ocean. It limits northwards with the region of Maule, southwards with the Region of Araucania, eastwards with Argentina and westwards with the Pacific Ocean.
Its capital city is Concepción concentrating 216.061 inhabitants. Is the second most populated region in the country, with a total of 1.861.562 inhabitants and a surface of 37.068,7 km2 which represents the 4, 9% of the Chilean continental and islander territory. Meantime the density reaches a 50, 2 inhab/km2.
The main urban centres are located at the coastal zone, standing out Tomé, Penco, Talcahunao, Coronel, Concepción, Lota, Arauco and Lebu. Even though more of the 80% of the region’s inhabitants live in urban zones (1.528.306), there are comunas (counties) where prevails the rural population, such as Florida, Contulmo, Quilaco, Alto Biobio, Cobquecura, Ñiquen and Peumo, among others.
Administrative organization
The Region of Biobio is divided in the following provinces:
– Ñuble: its surface is 511 km2 living in it 161.593 persons (84.946 women and 76.647 men). Is compound by the comunas (counties) Chillán, San Carlos, Ñiquen, San Fabián, Coihueco, Pinto, San Ignacio, El Carmen, Yungay, Pemuco, Bulnes, Quillón, Ranquil, Portezuelo, Coelemu, Treguaco, Cobquecura, Quirihue, Ninhue, San Nicolas and Chillan Viejo. Its capital city is Chillán and most of the population lives in urban zones (91, 72%).
– Biobio: it has a surface of 14.987,9 km2 with 353.315 inhabitants. It comprises the comunas (counties) of Los Angeles (its capital), Alto Biobio, Cabrero, Tucapel, Antuco, Quilleco, Santa Barbara, Quilaco, Mulchen, Negrete, Nacimiento, Laja, San Rosendo and Yumbel.The comuna (county) with the largest surface is Alto Biobio (2.124,6km2) and besides is the one that has been more recently created, December 2004.
– Concepción: it has a surface of 3.438 km2 and a total population of 912.889 persons. It is compound by the comunas (counties) of Concepción, Talcahuano, Penco, Tome, Florida, Hualqui, Santa Juana, Lota, Coronel, San Pedro de Paz, Chiguayante and Hualpén.
The one with the largest surface is Santa Juana (731, 2km2) whilst the smallest is Hualpén (53,5 km2), the latter was founded on March, the 13th.2004.
– Arauco: comprises 5.463, 3km2 and has157.255 inhabitants (117.569 at urban zones and 39.686 at rural areas). It is formed by the comunas (counties) of Lebu (the capital), Arauco, Curanilahue, Los Alamos, Cañete, Contulmo and Tirúa.
The largest is Cañete (1.089, 2 km2) whilst the smallest is Lebu (561,4 km2). Arauco is the one with more inhabitants (34.873).
Relief
In this zone we can distinguish the four characteristically forms of our national relief.
– Littoral plains: there are two zones. The first northbound the Biobio river which stands out for being highly eroded, having great cliffs and scarce zones with proper plains. Southwards the river is located the flattening Arauco-Cañete that has a width of 25 km and where the most important carboniferous deposits of the country are located.
– Coastal Ranges. Generally speaking, is low and in the region’s northern part is undulated with an average height that does not surpass the 400 masl and with river basins such as Quirihue.
After and southwards the Itata river, the range appears as an eroded high plateau with 650 m height and which most relevant hills are Quilme and Cayumanqui. Beyond the Biobio river, it takes the name of Nahuelbuta Ranges, there, reaches a 1.400 masl, extending until the Imperial river surroundings, in the Region of the Araucania.
– Intermediate depression: in its northern part has a considerable width reaching 100 km near Chillan, while, progressing southbound it decreases becoming narrower. Southwards the Biobío river, the plain is replaced by a strongly undulated sector.
– The Andes Ranges: it looses height as it advances southwards exceeding occasionally the 3.000 masl. Such is the case of some volcanoes which heights are the main summits of this ranges, such as Nevado of Chillan (3.212 masl) and Callaqui (3.164 masl).
Other important heights are the Antuco volcano (2.985 masl), the Copahue volcano (2.969) masl) and the Tolhuaca (2.780 masl), almost at the boundary with the Region of Araucania.
Hydrograph
The region’s most important hydro graphic basins are
– The Itata river: is born at the junction of the Cholguán and Huépil rivers and drifts by the region´s northern zone, draining a basin of 11.200 km2. Among its main affluents are the Diguillín, Larqui and Ñuble rivers, tghe latter is born at the slope of the Chillán volcano and its riverbed reaches the 5.100 km2. After drifting for 230 km. it flows into the ocean.
– The Biobío River: it has the country’s third largest basin after the Loa and Baker rivers, comprising 24.000 km2. Is born at the Gualletué and Icalma ranges lagoons located at the Region of the Araucanía, then drifts northbound through an inter mountainous valley of glacial origin receiving the contributions of smaller rivers, such as the Liucura, Pehuenco, Gualypulli, Pedregosos, Mitrauquén, Rahue and Lonquimay. In its middle flow receives the waters of the following rivers: Bureo, Culenco, Tavoleo, Guaqui and Laja. The latter is considered its main affluent and is born ath the Laja lagoon.
In its lower flow, the Biobío drags a great amount of sediment and reaches a width over the 2 km. It flows into the sea near Concepción after drifting for 380 km.
Other important water flows in this region are the Laja lagoon, the Lanalhue lake and the Lleulleu lake.
The first is located at theAntuco volcano slopes at 1.400 masl and is considered as the largest natural reservoir in the country. Meanwhile, the Lanalhue lake is located between Cañete and Contulmo and stands out as an attractive tourist resort; likewise the Lleulleu lake located slightly southwards the previous one. Both have a Coastal lagoon origin.
Climate
Once again we are located at a transitional zone, between the centre of the country, with a rather land-locked climate enabling the development of an intensive agriculture, and with our country’s own southern characteristics with greater humidity and precipitation. Thus, we can find the following climatic varieties:
– Warm template climate: with a 4 to 5 months of dry season: similar to the one at the region of Maule and dominating the northern part of the region of Biobío. It is characterised for having annual precipitations exceeding the 1.000 mm, afterwards, as off December and until March, there is a rain decrease registering only 40 mm monthly.
– Warm template climate: with a short dry season of less than 4 months, dominating great part of the region and characterised for abundant rain fall and a slight temperature decrease compared with the region’s northern zone, not exceeding as an average the 15°C.
– Rainy template climate with land-locked influence: is located at the region’s southern coast in the province of Arauco. Is characterised by abundant and constant rain fall and because the temperatures are low.
– Height climate: is at the highest summits of the Andes ranges. The precipitations are abundant and kind of snowy whilst temperatures descend due to the effect of heightness.
Biogeography
The soil quality and the zone’s prevailing humidity allow the growth of different species. It stands out the humid coastal deciduous forest, prevailing species as the Oak tree (Nothofagus obliqua), the Long Leaved Mañío (podocarus saligna), the Cinnamon (Drimys winteri), the Hazelnut (Gevuina avellana), the Chilean Bell-Flower (Lapageria rosea), the Myrtle (Luma apiculata), the Bay Tree (Laurelia sempervirens) and the Ulmo (Eucryphia cordifloia), among others.
Beyond the intermediate depression (highly modified) and where begins the first Andean ranges foothills; a deciduous type of forest develops. This is the same of the Region of Maule but it has species particularly adapted to more humid environments such as the Evergreen Beech (Nothofagus dombeyi), the Temu (Blepherocalyx divaricatum), the Raulí (Nothofagus alpine), the Colihuue (Chusquea coleu), the Magellan Barberry (Berberis buxifolia), the Oak Tree (Nothofagus oblique), the Cinnamon (drymis winteri) and also some climbing plants species such as the Chilean Bell-Flower (Lapageria rosea) the Pilpilvoqui (Cissus striata), the White Voqui (Boquila trifoliota), the Orange Voqui (Hydrangea serratifolia) and the Botellita (Mitraria coccinea).
At this formation highest parts this kind of forest incorporates species such as the Araucaria (Araucaria Araucana), the Ñirre (Nothofagus pumilio), the Anémona de Antuco (Anemone antucensis), the Maitencito (Maytenus distichia), and others.
Among the animals inhabiting this zone are the Quirquincho (Euphractus villosus), Piche (Euphractus pichy), the Andean Mole Rat (Chelemys macronyx) and the Southern Vizcacha (Lagidium viscacia), whilst the bird fauna is made of species such as the Bandurria (Theristicus caudatus), the Piquén (Cloephaga melanoptera), the Cóndor (Vultur gryphus), the black Woodpecker (Campephilus magellanicus), the Peregrine Falcon (Falco peregrinus) and the Blind Hen (Caprimulgus longirostris).
Protected wild areas
– Parque Nacional Laguna del Laja: is located at the pre Andean ranges of the Region of Biobío, between the 37°22´and the 37°30´latitude south, and the 71° 16´and the 71°28´longitude west. It extends across 11.600 hectares at heights that go from the 976 to the 2.979 masl.
It was created in 1958 and among its main attractions are the Antuco volcano (2.985 masl), the Laja Lagoon, with emerald green waters and El Torbellino and Las Chilcas waterfalls; from this same place borns the Laja river. It has also two typical tree species such as the Andes Ranges Cypress (Austrocedrus chilensis) and the Araucaria (Araucaria Araucana).
– Reserva Nacional Ralco: it is fully located at the Andes Ranges, between the 37°51´ and the 37°59´latitude south and the 71° 19´and 71°30´of longitude west. It has a surface of 12.492 hectares in which inhabits species such as lengas, ñirres and araucarias. As a fact, the reason for its founding was to preserve the latter species forests, as well as the living vegetation at the Callaqui volcano slopes.
– Reserva Nacional Los Huemules de Ñiblinto: it belongs to the comuna (county) of Coihueco, with a surface of 2.021 hectares in which lives one of the latest huemul population developing more northbound than its usual location. Also is possible to admire mature forests of coigües and oak trees in this place.
– Reserva Nacional Ñuble: it was founded in 1978; it belongs to the comuna (county) of Coihueco and has an extension of 55.948 hectares. Among its natural atractions stands out the Blanquillo waterfall, Hermoso valley, Los Peucos river and a lagoon glacially originated, among others. The characteristical flora is made of dwarf radales, hazelnuts, coigues and andean ranges cypresses, whilst the fauna is intergrated by cougars, vizcachas, huemules, condors and black woodpeckers.
– Reserva Nacional Isla Moche: is located in front of the Tirúa coasts, comprising an extension of 2.369 hectares. It stands out for its worldwide ecological importance since is considered an enviroment roughly intervened where inhabits species such as the White Bellied fardela (Puffinus creatopus).
