Quercus trojana Webb

TSO logo

Sponsor

Kindly sponsored by
The Trees and Shrubs Online Oak Consortium

Credits

Allen Coombes & Roderick Cameron

Recommended citation
Coombes, A. & Cameron, R., 'Quercus trojana' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/quercus/quercus-trojana/). Accessed 2021-11-28.

Genus

  • Quercus
  • Subgen. Cerris, Sect. Cerris

Common Names

  • Macedonian Oak
  • Trojan Oak
  • Fragno

Synonyms

  • Quercus macedonica A. DC.
  • Quercus grisebachii Kotschy

Infraspecifics

Other taxa in genus

Glossary

berry
Fleshy indehiscent fruit with seed(s) immersed in pulp.
acorn
Fruit of Quercus; a single-seeded nut set in a woody cupule.
dbh
Diameter (of trunk) at breast height. Breast height is defined as 4.5 feet (1.37 m) above the ground.
fastigiate
(of a tree or shrub) Narrow in form with ascending branches held more or less parallel to the trunk.
included
(botanical) Contained within another part or organ.
pollen
Small grains that contain the male reproductive cells. Produced in the anther.
taxon
(pl. taxa) Group of organisms sharing the same taxonomic rank (family genus species infraspecific variety).

Credits

Allen Coombes & Roderick Cameron

Recommended citation
Coombes, A. & Cameron, R., 'Quercus trojana' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/quercus/quercus-trojana/). Accessed 2021-11-28.

Tree to 18 m (lower in the wild), trunk 70–80 cm dbh, fast-growing, tardily deciduous, pyramidal habit, crown conical at first, later rounded. Bark greyish and fissured, cracks slightly orange when young. Branchlets covered in light down, greenish brown, soon becoming glabrous, greyish or brown; buds very small, ovoid, slightly acute, light brown and glabrous or nearly so, 2 mm long, terminal buds sport long, persistent, bristly stipules. Leaves leathery, oblong-oval or oblong-lanceolate, 3–10 cm long ×  1.5–5 cm wide, base slightly heart-shaped to rounded, apex acute or acuminate, margin wavy, bearing 4–7 pairs of short, spaced, ascendant, incurved teeth, mucronate or aristate; leaves emerge covered in sparse pubescence, upper surface becoming glossy green, glabrous or retaining short, scarce pubescence, underside paler and duller, covered in sparse, very short hairs; 6–12 pairs of veins, prominent below; petiole ribbed, sparsely pubescent, 2–8 mm long. Acorn cup hemispherical or bell-shaped, 1.5–2.2 cm deep × 2.2–3 cm wide, covering half to two thirds of the nut, scales quite spaced out, glabrescent or bearing grey pubescence, appressed and/or erect, spread out or reflexed, upper scales linear, 5 mm long; acorn ovoid or ellipsoid, light brown, 2.7–4.5 cm long, borne singly or in pairs on a very short stalk (2–5 mm long), base founded, apex silky (the rest glabrous), truncated, slightly depressed and navel-like, ripening in the second year. (le Hardÿ de Beaulieu & Lamant 2010).

Distribution  AlbaniaBosnia and HerzegovinaBulgaria (doubtful) GreeceItaly Southeast North MacedoniaMontenegroSerbiaTurkey Western Anatolia

Habitat Calcareous soils up to 1400 m asl, generally in pure stands, or in association with Q. frainetto, Q. cerris, Q. macrolepis, Q. pubescens, Q. infectoria, Pinus brutia, Juniperus excelsa, Abies cilicica, Styrax officinalis, Phillyrea spp., Carpinus orientalis, Ostrya carpinifolia and Fraxinus ornus.

USDA Hardiness Zone 7

RHS Hardiness Rating H6

Conservation status Least concern (LC)

The common names for this species in English, Macedonian Oak and Trojan Oak, reflect the major areas of distribution of this Mediterranean species: in the western Balkans and in Western Anatolia, where it was found by Webb and described in 1850. It is also native in southeastern Italy (Puglia and Basilicata), but opinion is divided as to whether this is evidence of a Miocene land connection between the heel of Italy’s boot and the Balkan Peninsula, or of introduction by Greek colonists, who wished to grow the oak for timber to build their ships (Bissanti 2004–2021).

It is described as ‘very hardy’ by Bean (Bean 1976), who avows he never saw it injured by frost; he also notes it is similar to Q. libani, but it differs in being a much stiffer tree, with shorter leaves of a greyer green, and much shorter leaf and acorn stalks. According to le Hardÿ de Beaulieu & Lamant (2010), its ecology is similar to that of Q. cerris, but it prefers dry, warm locations, where it shows relatively rapid growth, especially when young, and fruits at an early age.

The wood of Macedonian Oak has been particularly sought after for its strength and impermeability, which made it ideal for ship building. In Roman times, the wood was so valuable that forest landscapes were transformed due to the large number of trees felled. The timber was used for the construction of warships in the campaigns against Greece (perhaps taking a page out of the Greeks’ book, if it was indeed they who introduced the species to Italy), and to this day it is the preferred wood for building the hulls of fishing boats on the coast of Puglia (EUFORGEN 2021; Bissanti 2004–2021). The Venetian Republic used large quantities of Q. trojana wood for the construction and maintenance of its maritime port (le Hardÿ de Beaulieu & Lamant 2010).

The species was introduced to Kew in 1890. Several specimens planted in 1904 can be found there, grown from seed sourced from Italy, the largest reaching 21 m × 78 cm dbh in 2010 and ranking as the current height champion for UK and Ireland – it already measured 19 m × 56 cm in 1972 (Bean 1976). The UK girth champion grows at Tortworth and measured 19 m × 94 cm dbh in 2015; its age is not recorded but Elwes and Henry (1906–1913) mention a tree there that measured about 7.5 m × 19 cm dbh in 1907. The historic height champion used to grow at Batsford Arboretum and reached 24 m × 87 cm before bowing out in 1990 (Tree Register 2021). Trojan Oak grows in collections in France and Spain, but they are generally younger trees that have not yet reached adult size. There are several trees at the Jerusalem Botanical Gardens.

A tree grown as Q. trojana has prospered and proven drought resistant at UC Davis, California, spawning seedlings that are likewise successful in the Mediterranean conditions there. However, the specimen was grown from seed received from Kew and shows signs of hybridisation, perhaps with Q. cerris (Muffly 2020). Several US collections hold the taxon, wild-sourced from both Turkey and Europe (Quercus Multisite 2021). A specimen obtained as a seedling from Hillier Nurseries is to be found at Eastwoodhill Arboretum, New Zealand; trees grown from its acorns stand in nearby Hackfalls Arboretum, but they show an affinity to Q. libani, an indication that interloping pollen was involved somewhere along the line (Berry 2016).

Macedonian Oak was first described by P.B. Webb in a chatty letter to his brother in 1839 (conveniently published by Loudon in The Gardener’s Magazine), thrown in among a list of oaks he gathered in the Troad, an area that included the ancient ruins of Troy, hence the epithet referring to that city. He found it mixed with Q. macrolepis, which he names using the common name in Greek, velanida, and distinguished Q. trojana as being stiffer and more fastigiate than that species, with rigid leaves shining on both sides (Webb 1839).


'Iturraran Trinkoa'

A form of broadly columnar habit with ascending branches, spreading with age but remaining compact. Propagated from a tree at Iturraran Botanical Garden, Spain, it was originally called Q. trojana ‘Iturraran’. Trinkoa means compact in euskera.