Abies religiosa, sacred fir or in Nahuatl, oyamel is a fir native to the mountains of central and southern Mexico (Eje Volcánico Transversal, Sierra Madre del Sur) and western Guatemala. It grows at high altitudes of 2,100–4,100 metres (6,900–13,500 ft) in cloud forest with high rainfall and cool, humid summers and dry winters in most of its habitat regime but in the state of Veracruz to the east it grows with precipitations all year long. Regular winter snowfalls occur on the highest populations.
It is a medium-sized to large evergreen coniferous tree growing to 25–50 m (82–160 ft) tall with a trunk diameter of up to 2 metres (6.6 ft). The leaves are needle-like, flattened, 1.5–3.5 cm (0.59–1.4 in) long and 1.5 mm (0.059 in) wide by 0.5 mm (0.020 in) thick, dark green above, and with two blue-white bands of stomata below; the leaf apex is acute. The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they lie flat to either side of and above the shoot, with none below the shoot. The shoots are reddish-brown, hairless or with scattered pubescense. The cones are 8–16 cm (3.1–6.3 in) long and 4–6 cm (1.6–2.4 in) broad, dark blue-purple before maturity; the scale bracts are purple or greenish, of moderate length, with the tips exposed in the closed cone. The winged seeds are released when the cones disintegrate at maturity about 7–9 months after pollination. Trees from the western end of the range on Nevado de Colima, Jalisco have cones with larger, reflexed bract scales (similar to Noble fir cones); these are sometimes treated as a separate species, Abies colimensis.
Sacred fir is named after the use of cut foliage in religious festivals in Mexico, notably at Christmas. The oyamel is the preferred tree for the Monarch Butterfly (Danaus plexippus) to reside in colonies during its hibernation in Mexico. The distribution of this tree is narrowing because of deforestation and human impact.
- Conifer Specialist Group (1998). Abies religiosa. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 28 July 2006.
- "Abies religiosa (Kunth) Schltdl. & Cham.". Germplasm Resources Information Network. United States Department of Agriculture. 1999-10-12. Retrieved 2009-10-22.
- Liu, T. S. (1971). A Monograph of the genus Abies. National Taiwan University.