Beech

• 1. Introduction

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  Beech trees gave the English language its word for book. The Anglo-Saxon boc, the German buche, the Swedish box all meant both the tree and the written page. The connection traces back to old Runic tablets that were carved from beech wood. This single genus, known to botanists as Fagus, carries a name with roots reaching deep into Indo-European speech. So what is a beech, beyond a source of timber and a borrowed word? The answer spreads across two continents and fourteen species, from the silver-grey forests of Europe to a single South Korean island. It runs back through 81 to 82 million years of fossil pollen. And it threads into beer, smoked ham, drum shells, and a Gallo-Roman god worshipped in the Pyrenees. The story begins with a tree that is, at its heart, deceptively simple.

• 2. Form And Flower

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  Beeches are monoecious, which means a single tree carries both male and female flowers. The small flowers are unisexual. The female flowers appear in pairs, while the male flowers form catkins that rely on the wind to spread their pollen. The fruit that follows is a three-angled nut, set two at a time inside a spiny cupule that splits open when ripe. The bark of a beech is smooth, a trait that helps set the genus apart. Its leaves carry a central vein, with side-veins running parallel to one another and each ending in a tooth along the thin blade. Beech is deciduous, shedding its leaves in autumn. These shared features describe a genus that fossils show has been quietly diversifying for tens of millions of years.

• 3. Deep Time Origins

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  The oldest fossils tied to the beech lineage are pollen grains 81 to 82 million years old, recovered from the Late Cretaceous of Wyoming. Species have been named from a fossil record stretching all the way from the Cretaceous to the Pleistocene. Some were later reassigned to other genera entirely, including Alnus, Castanea, Juglans, and Nothofagus. Fagus holds a special position as the first diverging lineage in the evolution of the Fagaceae, the family that also contains oaks and chestnuts. The first members of the modern genus were likely present in the Paleocene of Arctic North America, in what is now western Greenland. From there the trees radiated quickly across the high latitudes of the Northern Hemisphere. Their first peak in diversity came in the Miocene of northeastern Asia. The contemporary species emerged through repeated reticulate evolution, meaning outbreeding, introgression, and hybridization tangled their family tree. The two subgenera, Engleriana and Fagus, split from each other in the Early Oligocene, between 32.1 and 33.4 million years ago.

• 4. Two Subgenera

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  Subgenus Englerianae lives only in East Asia, and it looks the part of an outlier. These are low-branching trees, often made of several major trunks with yellowish bark. Their nuclear DNA differs substantially from the other beeches, especially in the noncoding, highly variable spacers of the ribosomal RNA genes. A whitish bloom coats the underside of their leaves, the tertiary veins are visible, and the cupule-peduncle is long and smooth. Botanist Chung-Fu Shen proposed this grouping in 1992, though he never formalized it. His group held two Japanese species, F. japonica and F. okamotoi, and one Chinese species, F. engleriana. The status of F. okamotoi remains uncertain, but a recent treatment confirmed a third species, F. multinervis, endemic to Ulleungdo, a South Korean island in the Sea of Japan. The other subgenus, Fagus, gathers the better-known trees. These are high-branching, with tall stout trunks and smooth silver-grey bark. The group includes five species in East Asia, two in eastern North America, and a Western Eurasian complex of at least four species. Among the latter sits F. caspica, the Caspian beech, described as a new species in 2024 from the Talysch and Elburz Mountains.

• 5. A Tangled Family Tree

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  F. grandifolia, the American beech, ranges from East Texas and North Florida up to the St. Lawrence River in Canada. Its narrow endemic sister, F. mexicana, grows only in Hidalgo, Mexico, between 1400 and 2000 metres, where it joins the subtropical montane mesophilic forest known as bosque mesofilo de montana. The two differ subtly, with F. mexicana carrying slimmer leaves and a more polymorphic set of alleles. Across the Pacific, F. crenata, Siebold's beech, grows through the mountains of Kyushu, Shikoku, and Honshu and descends to sea-level in southern Hokkaido. Its history links it to both the Western Eurasian group and the other East Asian beeches. F. hayatae clings to the mountains of northern Taiwan, forming a cryptic sister pair with the Chinese F. pashanica. Several names in the genus have proven slippery. F. chienii, described from a single location in Sichuan, is probably extinct and possibly the same as F. lucida. F. sinensis was ruled invalid because its original material combined two very different species. In Western Eurasia the species blur into one another along morphological and genetical gradients, with F. hohenackeriana, the Caucasian beech, standing intermediate between F. caspica and F. orientalis. F. sylvatica, the European beech, is the close sister of F. orientalis.

• 6. Where Beech Grows

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  Beech wants a deep, well-drained soil that is neutral or slightly acidic, with a pH between 6 and 7.5. Its root system is shallow, which leaves it vulnerable to drought, and it will not live in waterlogged ground. Even so it tolerates wind, shade from other trees, and cold. In northern Europe it is a lowland species. Further south it climbs into the mountains, reaching altitudes of up to 1800 metres. The English Lowlands beech forests form an ecoregion of high-canopy woodland in southeastern England, dominated by European beech and surviving as remnants such as the 150 square mile New Forest. The species arrived in Britain after the last glaciation, and it may have been restricted at first to the basic soils of southern England. One theory holds that Neolithic tribes planted it for its edible nuts. In southeast Wales, the Cwm Clydach National Nature Reserve protects beech woodlands at the western edge of their natural range, set in a steep limestone gorge. The primeval beech forests of the Carpathians have been dominated by the tree since the last ice age. In North America the beech partners with the sugar maple to form Beech-maple forest, which some ecologists regard as a climax community.

• 7. Threats In The Bark

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  The beech blight aphid, Grylloprociphilus imbricator, is a common pest of American beech trees. A more serious threat is beech bark disease, a fungal infection found in the Eastern United States, Canada, and Europe. It begins with damage from the scale insects Xylococculus betulae and Cryptococcus fagisuga. After that, the fungi Neonectria faginata and Neonectria ditissima produce cankers each year, and these may eventually girdle and kill the tree. A newer danger is beech leaf disease, spread by the nematode Litylenchus crenatae mccannii. The disease was first discovered in Ohio in 2012. Since then it has spread through the Eastern United States and Canada, a reminder that even ancient lineages face fresh enemies.

• 8. Wood Word And Worship

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  The European beech yields a tough timber that weighs about 720 kilograms per cubic metre. It serves for furniture, flooring, plywood, and household items, and it can build chalets, houses, and log cabins. Beechwood also makes excellent firewood. In the kitchen and the brewery its uses multiply. The Roman statesman Pliny the Elder wrote in his Natural History that the fruit of the beech is the sweetest of all, recording that the people of Chios, when besieged, supported themselves wholly on mast. Spirals of beech wood, their flavour stripped with baking soda, are spread inside fermentation tanks for beers such as Budweiser to enlarge the surface area for the yeast. Beech logs are burned to dry the malt for German smoked beers, and the wood smokes Westphalian ham, traditional andouille from Normandy, and some cheeses. The genus reaches into culture as well. The pigment bistre was made from beech wood soot, and beech is one of the 38 plants used to prepare Bach flower remedies. The textile modal is a rayon often made wholly from cellulose pulped from beech wood, and some drum shells are built from the timber. The tallest beech hedge in the world, and the longest hedge in Britain, is the Meikleour Beech Hedge in Perth and Kinross, Scotland. The columnar Dawyck beech takes its name from Dawyck Botanic Garden in the Scottish Borders. In Gallo-Roman religion a god named Fagus, the Latin word for beech, was known from four inscriptions found in the Hautes-Pyrenees.