The Los Rios region’s landscapes are defined firstly by its temperate-rainy climate, without dry periods and water surplus. Secondly, by its geomorphology, characterized for being particularly mountainous, with the Andes Mountain Range, the Coastal Mountain Range and the Loncoche Massif; this latter chain crosses the region between both mountain ranges, from the region’s north border to the commune of Paillaco to the south. Further south is the intermediate depression between both mountain ranges, formed by relatively low, flat, and undulating land.

In this climatic and geomorphological context, the regional landscapes are mainly characterized by the presence of forests. Forests cover 62% of the region’s surface area, making Los Rios the region with the largest share of forests in Chile. Another characteristic trait are prairies and scrubland, which cover 27% of the regional surface area. By contrast, farmland is less frequent, accounting for only 1.2%. As noted, the region’s landscapes are outstandingly green since almost its entire surface area is covered by permanent vegetation or water bodies. This region is particularly remarkable for having the lowest share of surface area devoid of vegetation (2.5%). Certainly, another major feature of its landscapes are its numerous and extensive rivers, large lakes, and other water bodies, which account for 6.1 % of its surface area. This feature makes it into the region with the largest share of land occupied by water bodies in Chile. Water bodies are complemented by other watery landscapes, such as wetlands, snow, and glaciers, which, together, make up 1.1% of the region’s surface area.

Among the outstanding features of the Los Rios landscapes are several rainforest formations and the world-renowned Valdivian temperate forest, comprised by environments of dense forests crossed by numerous rivers and streams amidst the mountains. There are also landscapes dominated by the protected species araucaria araucana (Araucaria araucana) in the northeast and alerce (Fitzroya cupressoides) in the southwest. In summary, the typical landscapes of Los Rios are forested mountains, intermittently interrupted by rivers and lakes, and less rugged terrain with grasslands and scrublands.

The coast of the Los Rios region is characterized by its steepness; cliffs drop abruptly to the sea, with a few narrow elevated flat surfaces (marine terraces), alternating with narrow, dark sandy beaches, separated from each other by rocky promontories.

The Andean Mountain range generally reaches altitudes of 1,200 to 1,500 m, with its base (core) consisting of Andean plutons (massive crystalline igneous rocks, such as granite and diorite). On top are several volcanoes that expel rather dark-colored materials (basaltic and andesitic), some of which are still active.

Between both mountain ranges is the intermediate depression (or central depression) with altitudes between 50 and 300 m. Due to its topographic position, this flat to slightly undulating tectonic depression has been the deposit of rather large amounts of sediments, both marine and continental, including gravels, sands, silts, and clays.

The Los Rios region is the scene of several natural geological and hydrometeorological hazards, such as earthquakes, tidal waves, volcanic eruptions, lake and river flooding, and landslides of different magnitudes, among others. Examples include the earthquake of May 22, 1960 –the world’s most powerful temblor in recorded history– which caused the sinking of the coastal area and the subsequent development of extensive wetlands; and the powerful volcanic eruption of the Cordón Caulle in the winter of 2011.

The Los Rios region is located in the so-called zone of calm rivers with lake regulation. Depending on the watersheds’ location and development, coastal, Andean and trans-Andean basins can be found.

Most of the region is located on the surface of two large basins: the Valdivia River and the Bueno River. An interesting feature of the hydrographic system of the Los Rios region is the location of a series of lakes throughout the Andean foothills. All of these lakes take tributary rivers from the Andean region but only two send effluents (outfalls) directly to the Pacific: The Riñihue and Ranco lakes.

The final stretch of the San Pedro / Calle Calle/ Valdivia River is an estuary, meaning it is under the impact of tides, with rising and falling currents alternating approximately every six hours. Therefore, its waters are brackish with an intermediate salinity between oceanic and strictly fluvial waters. The influence of the tides is felt upstream up to about 50 km from the mouth.

This region’s total surface area amounts to approximately 18,430 square kilometers. The landscapes display its current land uses, i.e., the type of activity carried out, with the following surface areas: forests, 61.9%; grasslands, 23.1%; water bodies, 6.1%; scrublands, 3.8%; areas without vegetation, 2.5%; agricultural land, 1.2%; wetlands, 0.7%; snow and glaciers, 0.4%; and urban and industrial areas, 0.4%.

The region’s soils are formed by volcanic materials (more than 80% of its surface area), especially ash from volcanic eruptions. These soils prevail in most of the Andes Mountains, valleys and highlands of the intermediate depression, and the eastern foothills of the Coastal Range.

The soils that prevail in the Coastal Range are derived from metamorphic mica schist rocks, commonly called flagstone, forming highly evolved soils (Ultisols) and recently developed soils (Inceptisols), in summit environments with high geological erosion.

The Los Rios region is a territory mainly covered by forests (61.9 % of its surface area), with 11,351 square kilometers distributed throughout the region, but mainly in both mountain ranges. Native forests account for 82% and forest plantations for 18% of forests throughout the region.

What is a forest? Article 2 of Law 20283, on Native Forest Recovery and Forestry Promotion, defines forest as follows: “A site populated with plant formations in which trees predominate and which occupies an area of at least 5,000 square meters, with a minimum width of 40 meters, with tree canopy coverage that exceeds 10% of that total area in arid and semi-arid conditions and 25% in more favorable circumstances”.

And what is a native forest? This same law defines native forest as: “Forest formed by native species from natural generation, natural regeneration or plantations under canopy with the same species existing in the original distribution area, which may have an accidental presence of exotic species randomly distributed”. Native forests present great diversity and are therefore classified into forest types, which correspond to certain compositions of dominant species scientifically defined by the forest’s own ecology and dynamics, and recognized in Chilean legislation.

Of the 12 forest types in Chile, nine are present in Los Rios. The most extensive forest types are coihue-raulí-tepa (30.9 %), roble-raulí-coihue (27.8 %), evergreen (22.7 %), and lenga (15.7 %). The other forest types cover a small area (3 % in total): araucaria, larch, Magellan coihue, sclerophyllous and Guaitecas cypress.

In the Los Rios region there are also 210,000 hectares of plantations, mainly of Monterey pine (Pinus radiata, 56 %), eucalyptus (Eucalyptus nitens, Eucalyptus globulus, 41 %), Douglas fir (Pseudotsuga menziesii, 2.4 %), poplar (Populus spp.), Australian blackwood (Acacia melanoxylon) and other species, including some native species. The plantations are characterized by being made up of a single tree species, with same-age trees homogeneously distributed. The plantations are characterized by being made up of a single tree species, with same-age trees homogeneously distributed.

Wetlands are aquatic ecosystems that include permanently or temporarily flooded areas, vegetation adapted to waterlogged conditions –called hydrophytic or “water loving” vegetation– and hydric soils, i.e., soils with characteristics typical of water-saturated environments. These are key components for biodiversity and wildlife, basin water regulation, recreation, tourism, etc.

The Los Rios region’s wetlands are essential components of its landscapes and ways of living, with approximately 150,000 hectares of marshlands –both in urban and rural areas– accounting for 8.1% of the total surface area.