| Zdroj: |
info:cnr-pdr/source/autori:Paula Marchelli, Javier Sanguinetti, Fernanda Izquierdo, Birgit Ziegenhagen, Angela Martín, Claudia Mattioni, and Leonardo A. Gallo/titolo:Low Intensity Breeding of Native Forest Trees in Argentina/titolo_volume:/curatori_volume:/editore:/anno:2020 |
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Pewen, Araucaria araucana (Molina) K. Koch (also known as monkey puzzle tree), is a dioecious large-seeded emergent conifer endemic to the northern region of the temperate forests of Argentina and Chile. The species integrates the Araucariaceae family, with an ancient origin in the Triassic (ca. 250 My BP), being the only one among the 19 species of the taxa which lives in temperate climate Araucaria araucana is currently at risk of extinction (Farjon and Page 1999), included in the Appendix I of CITES (http://www.cites.org/eng/app/appendices. shtml) and listed in the 2012 IUCN Red List of Threatened Species (http://www. iucnredlist.org) as an endangered species. Although currently protected in both countries, the species was overexploited for its timber of extraordinary value. Its high morphic coeffcient (> 0.80) and the basic density of its wood (0.50-0.60) (CONAF 2013), appropriate for the industry, were the two main reasons for its exploitation. However, the threat is increased given its restricted distribution, slow growth and limited dispersal ability and mainly because of its poor regeneration and continued decline due to diverse anthropogenic causes, such as fres, seed harvest, overgrazing and exotic wild mammal invasions (Gallo et al. 2004a; Sanguinetti 2008; Premoli et al. 2013; Mundo et al. 2013; Tella et al. 2016). In addition, the species is recently going through a general decay expressed as foliar damage in branches and crowns, causing sometimes the death of the tree (Saavedra and Willhite 2017; Vélez et al. 2018). Pewen trees can reach a height of 50 m, a diameter of 2 m and ages of up to 1000 years (Aguilera-Betti et al. 2017). Young trees develop a pyramidal form, while matures often lose lower branches, giving the tree an umbrella-like shape with the distal part of the branches upwards oriented ("Pewen" in the Mapuche language means "the one who looks at the sky") (Fig. 7.1). It is a dioecious tree; male cones are 8-12 cm long and female cones 15-20 cm in diameter containing 120-180 seeds of 4-5 cm long (Fig. 7.1) (Gut 2008). Pewen has exceptional cultural and economic relevance (Aagesen 1998) and is considered sacred by the Mapuche Pewenche people (Herrmann 2006). The edible seed is a pine nut (locally called piñón) and has long been a major element of the diet of the Mapuche Pewenche communities living in and around its natural distribution range (Aagesen 1998). Seeds are also used to feed livestock and constitute a family income when selling and/or exchanging them for food (Herrmann 2006), also as processed products (Cortés et al. 2019). The management of seed collection performed by the Mapuche people involves sociocultural ancestral knowledge, but the economic market pressure for this non-timber forest product and the new assemblage of wild non-native seed feeders creates a novel and more complex socioeconomic and environmental scenario for conservation. |
