Abies hickelii Flous & Gaussen

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Credits

Tom Christian (2021)

Recommended citation
Christian, T. (2021), 'Abies hickelii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/abies/abies-hickelii/). Accessed 2021-07-25.

Genus

Common Names

  • Hickel's Fir
  • Oyamel
  • Pinabete

Synonyms

  • Abies oaxacana Martínez
  • Abies hickelii var. oaxacana (Martínez) Farjon & Silba
  • Abies religiosa subsp. hickelii (Flous & Gaussen) Strandby, K.I. Chr. & M.Sørensen

Glossary

dbh
Diameter (of trunk) at breast height. Breast height is defined as 4.5 feet (1.37 m) above the ground.
included
(botanical) Contained within another part or organ.
key
(of fruit) Vernacular English term for winged samaras (as in e.g. Acer Fraxinus Ulmus)
pectinate
Comb-like.
resin canal
Minute tubes containing resin-producing cells in the leaves and wood of conifers.
variety
(var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.

Credits

Tom Christian (2021)

Recommended citation
Christian, T. (2021), 'Abies hickelii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/abies/abies-hickelii/). Accessed 2021-07-25.

Tree to 30 m, 1–1.3 m dbh. Crown narrowly conical at first, flat-topped, irregular, and open in mature trees. Bark of young trees smooth, grey, lenticillate, becoming thick, deeply fissured and breaking into irregular plates at the base of old trees. First order branches spreading horizontally; second order branches horizontal or slightly upswept. Branchlets slender, reddish- or purplish-brown, ridged and grooved, often puberulent in grooves when young, later glabrous. Vegetative buds ovoid-globose, 5 × 4 mm, with a dense covering of yellowish resin. Leaves densely set, pectinate in two lateral sets of equal length or those above slightly shorter, ~perpendicular to shoot, (1.2–)1.8–3.5 cm × 1–1.8 mm, base twisted or curved, apex emarginate or obtuse, glossy green above, somewhat glaucous beneat with two silvery-white stomatal bands separated by a prominent midrib; leaves with 4–12 resin canals. Pollen cones short, yellow with red microsporophylls. Seed cones short-pedunculate, oblong-cylindrical, 6–10(–12) × 2.5–3.5(–5) cm, apex obtuse, maturing from dark blue-purple to dark purple-brown; seed scales cuneate-flabellate, 1.3–1.5 × 1.8–2 cm at midcone; bracts exserted, upright or outspreading (not recurved, except at maximum maturity), pruinose. (Farjon 2017Debreczy & Rácz 2011).

Distribution  Mexico Principally in northern Oaxaca, but also in Chiapas, Gurrero, Puebla and Veracruz

Habitat Montane forests between 2400–3400 m asl, with Pinus montezumae, P. pseudostrobus, P. ayacahuite, and several Quercus species.

USDA Hardiness Zone 8

RHS Hardiness Rating H5

Conservation status Endangered (EN)

Taxonomic note A variety, var. oaxacana, is sometimes regonised. Ironically, Farjon (2017), a ‘lumper’, recognises it, whereas Debreczy & Rácz (2011), confirmed ‘splitters’, do not. Descriptions attest to some overlap between the two, and it probably just represents one end of the species’ spectrum. Here we tentatively follow the latter authors and place it into synonymy.

Abies hickelii is native to sub-tropical southern Mexico where it is found at considerable altitude. Its lofty distribution is probably a key factor rendering it hardy in cultivation in Britain: there is a superb young tree at the Yorkshire Arboretum raised from Jim Russell’s collection JR 426. In February 2021 this was 13.5 m × 39 cm dbh (J. Grimshaw pers. comm. 2021). A Tree Register record of A. hickelii var. oaxacana, at Castlewellan in Northern Ireland, is unconfirmed. A. hickelii is allied to A. religiosa, A. guatemalensis, and A. vejarii, but differs from all of them in subtle ways. The very limited range of material in cultivation suggests it is distinguished by its pectinate, glossy-green shade needles of more or less equal length (cf. needles in the upper rank being shorter in many species) and more or less perpendicular to the shoot (cf. somewhat forward), but the most remarkable difference is in the preponderance of resin canals in the needles.

Nearly all fir species have two resin canals per leaf, and their position – in the ‘interior’ of the leaf tissue or toward the edges – is often cited as an important character in differentiating taxa. This question of resin canal position within leaves is largely ignored in this account for various studies have shown it to be unstable (see the genus description for further discussion), but for the number of resin canals to alter from the standard two-per-leaf is much harder to ignore. With anywhere between 4 and 12 canals A. hickelii is one of only four firs worldwide known to have more than two: the others are A. firma (with 2–4 canals per leaf); A. hidalgensis (4–7, but not not in cultivation); A. zapotokensis (4, but here tentatively included within A. guatemalensis) (Debreczy & Rácz 2011). It is curious that other than A. firma of Japan, all these firs are native to Mexico and Mesoamerica.