Valdivian Temperate Rainforest
The Valdivian temperate rainforest covers a long strip of cool wet land in southern Chile and Argentina. Most people picture rainforests as hot and tropical, but this one is cool, wet and dotted with snow-capped volcanoes. It is one of only a handful of temperate rainforests in the world, and is home to giant evergreen trees that can live for over 3,000 years.
- Areaapprox. 250,000 km²A long thin strip down the western Andes
- CountriesChile, ArgentinaMostly in Chile
- TypeTemperate rainforestCool and wet rather than hot and humid
- Famous treeAlerceCan live 3,000+ years
- RainfallOver 2,500 mm/yearSome parts get over 6,000 mm
- Famous animalPuduThe smallest deer in the world
The Valdivian compared to tropical rainforests
The Valdivian is small compared to the tropical giants but is the second largest temperate rainforest on Earth (after the Pacific Northwest rainforest of Canada and the United States).
What is a temperate rainforest?
A temperate rainforest is a forest that gets a lot of rain (usually more than 2,000 mm per year) but is cooler than a tropical one. It has the moisture of a rainforest but with temperatures more like a British woodland. Temperate rainforests are rare; they only exist where moisture-laden winds from the ocean meet a mountain range that forces the air upwards, dumping huge amounts of rain.
There are only a handful of temperate rainforests left in the world: the Pacific Northwest of Canada and the United States, the western coast of Norway, parts of Tasmania and New Zealand, and the Valdivian in Chile.
The alerce: an ancient tree
The most famous tree of the Valdivian is the alerce, a giant evergreen relative of the giant sequoia. Alerce trees can grow over 50 metres tall and live for more than 3,000 years. One alerce in Chile, called the Gran Abuelo (Great Grandfather), is thought to be around 5,000 years old, which would make it one of the oldest individual organisms on Earth.
The wood of the alerce is rot-resistant and was heavily logged for centuries, until protection finally arrived in 1976. Many of the biggest old-growth trees were felled before then. Today the alerce is protected as a Chilean Natural Monument.
Unique wildlife
The Valdivian is full of species found nowhere else. There is the monito del monte (a tiny tree-dwelling marsupial that is more closely related to Australian possums than to other South American mammals, a leftover from when Antarctica connected the two continents). There is the southern river otter, the Andean condor, the magellanic woodpecker, and the dwarfs of mountain hummingbirds.
Deeper dive: the Gondwanan connection, Nothofagus and conservation
The Valdivian temperate rainforest is one of the great Gondwanan relict forests of the southern hemisphere. Many of its dominant trees, especially in the Nothofagus or southern beech family, have close cousins in southern Australia, Tasmania and New Zealand. These distributions show how the southern continents were once joined together as the supercontinent Gondwana, with a vast cool wet forest stretching across all of them. When Gondwana broke up around 100 million years ago, the trees were carried apart on the drifting continents but their family ties remain visible today.
The monito del monte (Dromiciops gliroides) is one of the most striking biogeographical curiosities in the Valdivian. It is the only living member of an order of marsupials called Microbiotheria. Its closest living relatives are not in South America at all but in Australia, again reflecting the Gondwanan connection. Genetic studies suggest the lineage split from the ancestors of Australian marsupials approx. 60 million years ago, when Antarctica was still warm enough to support the connecting forest.
About half of the original Valdivian forest has been cleared, mostly for cattle pasture, eucalyptus and pine plantations, and (most recently) salmon farming infrastructure. Conservation has been complicated by the fact that the temperate rainforest crosses national borders and contains valuable timber resources. Important protected areas now include Alerce Andino National Park, Pumalin Park (donated to the Chilean nation by the late Doug Tompkins) and the vast Parque Nacional Patagonia. Restoration projects are also working to remove invasive non-native plantations and re-establish native forest.
The country that holds most of this forest is Chile. The tropical giant rainforests are the Amazon and the Congo.