Species Spotlight: Quercus kotschyana O.Schwarz

Otto Schwarz, a 19th-century German botanist, encountered several oak trees among the cedars while visiting the famous cedar forest of Bsharre in Lebanon. He named this species Quercus kotschyana in honor of Theodor Kotschy (1813−1866), a botanist who studied the flora of the Near East. This name fell into obscurity, and Paul Mouterde, who compiled an exhaustive inventory of the flora of Lebanon and Syria, mistakenly referred to it as Q. pinnatifida C.C.Gmel. (Mouterde 1966). Initially, this taxon was described in Germany based on a single individual that bore no fruits and was considered a variety of Q. lanuginosa (Mouterde 1966; Gmelin 1826). According to Govaerts & Frodin (1998), Q. pinnatifida is no longer in use and is considered a synonym of Q. pubescens Willd. subsp. pubescens, which is found in Europe and Turkey but has not been recorded in Lebanon (Roskov et al. 2015).

Moreover, Abi Saleh et al. (1996) and later Tohme & Tohme (2014) did not delve deeply into the taxonomy of the species, instead following the same nomenclature and describing the presence of Q. pinnatifida in Lebanon, particularly on the western slopes of northern Mount Lebanon, in locations such as Danniyeh, Ehden, the Cedars of Bsharre, Tannourine Cedars, and Sannine.

Stephan and Teeny (2017) revised the nomenclature and examined the holotypes used to name the species in the Natural History Museum of Stockholm. They conducted morphometric analyses on leaves and acorns collected from the aforementioned sites (Stephan et al. 2018) and concluded that the accepted name for the species is Q. kotschyana, which is endemic to Lebanon.

Govaerts & Frodin (1998) suggest that the Kotschy oak is a probable hybrid of Q. pubescens and Q. cerris, with some similarities to Q. vulcanica. Molecular analyses of the oaks in Lebanon confirmed that it is an endemic species belonging to the group of White Oaks, with possible relations to other oaks of the same group found in Turkey (Douaihy et al. 2022).

These trees can grow very tall, reaching heights of over 25 m (as seen in the Horsh Ehden Nature Reserve), and their diameter can exceed 1 meter in the oldest specimens. The leaves are pinnatifid, resembling those of Q. cerris, but with deeper sinuses that may reach the central vein. The leaf blade is strongly leathery, measuring 6−12 cm in length and 3.2−6.5 cm in width, and is round-oval to oblong-lanceolate in shape. The lobes are broadly linear, acuminate, and have distinct sinuate margins. The acorns are borne on thick, tomentose peduncles, clustered (two to six) in short racemes at the axis of the apical leaves.

The habitat corresponds to the Montane Mediterranean vegetation stage, between 1,500 m and 2,000 m above sea level. This tree is associated with the cedar vegetation series (Abi Saleh et al. 1976, 1996) and grows alongside Cedrus libani, Juniperus excelsa, Acer hyrcanum subsp. tauricola, A. monspessulanum subsp. microphyllum, and Q. petraea subsp. pinnatiloba (syn. Q. cedrorum). The latter is almost the only oak that grows alongside it, as other species do not share the same environmental requirements.

This species requires cool, humid, mesic conditions and is confined to a few suitable locations in Mount Lebanon, making it vulnerable to climate change (Stephan et al. 2022). The tree is not currently exploited, and although it exists in some protected areas, there is no active management in place. The IUCN Red List of Threatened Species lists Q. kotschyana as Endangered (Stephan 2018).

Works cited

Abi-Saleh, B., M. Barbero I. Nahal, and P. Quezel. 1976. Les séries forestières de végétation au Liban, essai d’interprétation schématique. Bulletin de la Société Botanique de France 123: 541–560. Available from: https://www.tandfonline.com/doi/abs/10.1080/00378941.1976.10835710 

Abi Saleh, B., S. Safi, N. Safi, R. Hanna, N. Nasser, and H. Tohme. 1996. Étude de la diversité biologique du Liban : Flore terrestre. Ministère de l’Agriculture et Programme des Nations-Unies pour l’Environnement. GF/6105-92-72. Beyrouth, Liban.

Bussotti, F., and P. Grossoni. 1998. Des problèmes dans la classification des chênes Taxonomie en Europe et région méditerranéenne. Forêt Méditerranéenne, tome XIX (3): 267−278. Available from: https://www.researchgate.net/publication/285740495_Des_Problemes_dans_la_classification_des_chenes 

Douaihy, B., C. Saliba, J. Stephan, M.C. Simeone, S. Cardoni, P. Farhat, and M. Bou Dagher Kharrat. 2020. Tracking diversity and evolutionary pathways of Lebanese oak taxa through plastome analyses. Botany Letters 167(3): 315−330.

Gmelin, C.C. 1826. Flora Badensis, Alsatica et confinium regionum cis et transrhenana plantas a lacu Bodamico usque ad confluentem Mosellae et Rheni sponte nascentes: exhibens secundum systema sexuale cum iconibus ad naturam dileneatis. Karlsruhe: Officina A. Mülleriana. Available from: http://www.biodiversitylibrary.org/item/29529#page/683/mode/1up

Govaerts, R. and D.G. Frodin. 1998. World checklist and Bibliography of Fagales. Royal Botanic Gardens, Kew.

Mouterde, P. 1966. Nouvelle Flore du Liban et de la Syrie. Tome premier. Editions de l’Imprimerie Catholique, Beyrouth.

Roskov, Y., L. Abucay, T. Orrell, D. Nicolson, T. Kunze, A. Culham, N. Bailly, P. Kirk, T. Bourgoin, R.E. DeWalt, W. Decock, and A. De Weve. 2015. Species 2000 & ITIS Catalogue of Life. Naturalis, Leiden, the Netherlands. Available from: www.catalogueoflife.org

Stephan, J. 2018. Quercus kotschyana. The IUCN Red List of Threatened Species 2018: e.T194180A2303139. https://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T194180A2303139.en. 

Stephan, J., C. Bercachy, J. Bechara, E. Charbel, and J. López-Tirado. 2020. Local ecological niche modelling to provide suitability maps for 27 forest tree species in edge conditions. iForest-Biogeosciences and Forestry 13(3): 230. Available from: https://iforest.sisef.org/abstract/?id=ifor3331-013 

Stephan, J., and P. Teeny. 2017. Revealing the taxonomy of an endemic oak of Lebanon. Plant Sociology, 54(Suppl. 1): 97−100. Available from: https://www.researchgate.net/publication/322751763_Revealing_the_taxonomy_of_an_endemic_oak_of_Lebanon 

Stephan, J. M., P.W. Teeny, F. Vessella, and B. Schirone. 2018. Oak morphological traits: between taxa and environmental variability. Flora 243: 32−44.

Tohme G., and H. Tohme. 2014. Illustrated Flora of Lebanon. CNRS Editions, Beirut.

Photos © Jean Stephan