The larch: witness of a climatic evolution of more than 3000 years

This tree from Argentine and the Chilean Patagonia, grows in the Valdivian forest and can reach 50 m in height, 4 m in diameter and 3000 years of age  .

Larch tree forest

This type of tree can last up to 3000 years. / Photo: Pixabay

LatinamericanPost| Juan Manuel Bacallado

Listen to this article

Leer en español: El alerce: testigo de una evolución climática de más de 3000 años

Larch characteristics and distribution in Patagonia

The larch belongs to the cupressaceae family, and is one of the longest-living trees in the world. It develops on humid soils, with annual rains of more than 2000 mm, associated with species such as the guaitecas cypress, the female maniú and the coihue.

According to WWF (World Wide Fund for Nature) of Chile , “the larch is a conifer endemic to South American subantarctic forests, developing discontinuously between parallels 39º50´ and 43º30´ south latitude, mainly in Chile and to a lesser extent in sectors adjacent in Argentina. "According to the report Some Species in Danger (May 2020) of this environmental organization," currently there are some 260,000 ha of larch forests, less than half of the area that originally existed. "

Importance of the species and conservation status

By virtue of its longevity and slow growth, the study of the growth rings (Dendrochronology) of the larch allows us to analyze the climate of another era, volcanic activity, and other environmental factors. "Recent research of this type on larch (Fitzroya cupressoides), have allowed temperature reconstructions to be carried out for the last 3,620 years, and have shown that larch is the second longest-living species on the planet" (Alerces, millennial witnesses to the planetary climate, magazine Environment and Development, Chile, 1994).

For its protection, the larch has been included in Appendix I of CITES (acronym in English for the Convention on International Trade in Endangered Species of Wild Fauna and Flora). According to the IUCN (International Union for Conservation of Nature) Red List of threatened species , the larch is Endangered, and its population is decreasing.

By Decree 490 of 1976, the Chilean Ministry of Agriculture declared the larch a Natural Monument. The Senate of the Argentine Nation, for its part, declared it a Natural Monument in 2016, on the basis of article 8 of Law 22351 on National Parks, which establishes: “Natural Monuments will be areas, things, living species of animals or plants , of aesthetic interest, historical or scientific value, to which absolute protection is accorded ”.

The main threats to the larch have been the exploitation of its wood, and the fires intended to open grazing fields in the forest, and to exploit the trees killed by the fire. Livestock farming has also affected the species: "browsing through native fauna or exotic livestock of both species affects renovations of up to 1.5 m, as well as the lower branches of taller individuals" (Architecture of the larch and the cypress of the Guaitecas, Javier Grosfeld, CONICET -North Patagonia Scientific-Technological Center-, Bariloche, Argentina).

Because the wood of this species is almost rot-proof, it has been used for the construction of boats and houses in southern Chile, and especially for the development of tiles (a type of tile made through longitudinal cuts of timber). These tiles, a kind of fish scales that cover the wooden constructions, are characteristic of the Churches of the archipelago of Chiloé, Chile, which were declared a World Heritage Site by UNESCO (United Nations Educational, Scientific Organization and Culture) in the year 2000.

Also read: Blue forests, the new protagonists of planet earth

Larch forests in protected natural areas

Several protected natural areas owe their name to this species: Alerce Costero National Park and Alerce Andino National Park, both from CONAF (National Forest Corporation), Chile, and Los Alerces National Park, Argentina, declared a World Heritage Site by UNESCO in 2017.

On its website, the IUCN (International Union for Conservation of Nature) states that “Los Alerces National Park, in Argentina, has been inscribed on the World Heritage List following the recommendation of IUCN, the official advisory body on nature for the World Heritage Committee. This place protects some of the last portions of the Patagonian Forest and is home to the Patagonian larch, the second longest-living species of tree on Earth, and which is in danger of extinction ”.

Other protected natural areas also provide shelter to the species, although they do not bear its name. CONAF of Chile states that “the Pumalín Douglas Tompkins National Park was created on February 28, 2018 by Decree No. 28 of the Ministry of National Assets. In 2005, being a private protected area, it was declared a Nature Sanctuary, according to Exempt Decree No. 1,137 of August 18, 2005 of the Ministry of Education. ” CONAF adds, in its site on this park, that it "has larch forests, a threatened and protected species as a natural monument and existing forest species such as: luma, tepa, canelo, tineo, tiaca, coigüe de Chiloé, coigüe de Magallanes, ulmo; olive and male mañío ”. This park has the particularity that its lands were donated by Douglas Tompkins, a North American philanthropist who also ceded land to the Argentine government to create the Iberá National Park, refuge of the largest wetland in South America after the Brazilian Pantanal.

Preserving larch is protecting a living heirloom

The original larch forest has been cut in half. Of this surface, "only 17% (42 thousand hectares) is protected in the System of Protected Areas of the State (SNASPE)", according to the Ministry of the Environment of Chile. Given this situation, it is essential to establish environmental policies that contribute to conserving this tree, the largest in South America and a silent witness to thousands of years of life on the planet.