Libocedrus Tetragona

''Pilgerodendron'' is a genus of conifer belonging to the cypress family Cupressaceae. It has only one species, ''Pilgerodendron uviferum'', which is endemic to the Valdivian temperate rain forests and Magellanic subpolar forests of southern Chile and southwestern Argentina. It grows from 40 to 55°S in Tierra del Fuego, where it is the southernmost conifer in the world. It is a member of subfamily Callitroideae, a group of distinct Southern Hemisphere genera associated with the Antarctic flora.Farjon, A. (2005). ''Monograph of Cupressaceae and Sciadopitys''. Royal Botanic Gardens, Kew. Flora Chilena
''Pilgerodendron uviferum''
/ref>

''Pilgerodendron'' is very closely related to the New Zealand and New Caledonian genus ''Libocedrus'', and many botanists treat ''P. uviferum'' within this genus, as ''Libocedrus uvifera'' (D.Don) Pilg.Eckenwalder, J. E. (1976). Re-evaluation of Cupressaceae and Taxodiaceae: a proposed merger. ''Madroño'' 23 (5): 237-256. It is also a taxonomical synonym for ''Libocedrus tetragona'' (Hooker). The species is known locally as ciprés de las GuaitecasChilebosque
''Pilgerodendron uviferum''
/ref> (after the Guaitecas Archipelago), and elsewhere by its scientific name, as pilgerodendron. The genus is named after Robert Knud Friedrich Pilger.

''P. uviferum'' is a dioecious, slow-growing, narrowly conical evergreen tree that grows from 2–20 m in height, with a trunk up to 1.5 m in diameter. Taller specimens and wider trunks (reportedly up to 3 m in diameter) are known to have existed before it was overexploited. The leaves are scale-like and arranged in decussate pairs, with each leaf equal in size, giving the shoots a square cross-section (unlike the ''Libocedrus'' species, where pairs of larger leaves alternate with pairs of smaller leaves, giving a somewhat flattened shoot). The seed cones are 5–12 mm long and 4–6 mm broad, with four scales, two sterile basal scales and two fertile scales; each scale has a slender spine-like bract, and each fertile scale has two winged seeds 3–4 mm long. The pollen cones are 5–10 mm long and 2 mm broad, with 12–20 scales.

It is found in the evergreen coastal lowland forests along the Pacific coast of southern Patagonia, in association with the broadleaf evergreens '' Nothofagus betuloides'' and '' Drimys winteri''. It is also found in open stands in sheltered bogs farther inland, where it is often locally dominant, and ranges as far as the eastern slopes of the Andes in southwestern Argentina. At the northern end of its range it is found in association with ''Fitzroya cupressoides''. It has also been planted along the northern part of the Pacific Coast of the United States.

At present much ''Pilgerodendron uviferum'' grow in the Andes and in the Chilean Coast Range. However, during the interstadials of the region's last glacial period, ''P. uviferum'' grew in lowland areas such as the Central Valley, where it is now absent. Remaining lowland populations are thought to be relicts that have survived the warmer climate of the Holocene.

The wood of ''P. uviferum'' is yellow-reddish and has a distinct spicy-resinous smell, and is highly resistant to decay, which has made it very valuable as a source of timber for building construction in its native range. Much of its original lowland habitat has been cleared for this and other reasons. Listed as Vulnerable (VU A2cd v2.3) Due to over-exploitation, the species is now much scarcer than formerly, and is accordingly listed under CITES Appendix I, meaning commercial international trade is prohibited. ''P. uviferum'' is considered threatened by the World Conservation Monitoring Centre and vulnerable by the International Union for Conservation of Nature.

History

Indigenous sea-faring nomads of the Chono and Kawésqars groups used ''Pilgerodendron uviferum'' as firewood as well as wood for rows, boats and houses. During the Antonio de Vea expedition (1675–1676) Spanish explorers visited the Guaitecas and Chonos archipelagoes where the tree grew noticing the similarity to the "cypresses of Spain".

Historically the wood was used to make railway sleepers, but eventually became popular for use as timber in all types of construction. In the 1860s, Felipe Westhoff was one of various businessmen who exported ''Pilgerodendron uviferum'' north to Chilean and Peruvian ports. Westhoff, who was based in Ancud, came initially as an agent of Ferrocarril Central Andino in Peru to purchase sleepers but soon became an independent businessman.

The town of Melinka was established in 1860 during the ''Pilgerodendron'' boom. This was the first permanent settlement in the Guaitecas Archipelago. After Westhoff's retirement in the 1870s, Ciriaco Álvarez, a native of Chonchi, rose as the most prominent ''P. uviferum'' businessman in the area, and was dubbed "The King of Pilgerodendron" ( es, El Rey del Ciprés). Many of the wooden structures in settlements of the southern Chilean archipelagos are built largely from ''P. uviferum'' wood.

References

{{Taxonbar, from=Q133103

Cupressaceae
Valdivian temperate rainforest
Trees of mild maritime climate
Trees of subpolar oceanic climate
Monotypic conifer genera
Garden plants of South America
Ornamental trees
Dioecious plants