European hornbeam (Carpinus betulus)
Between Nash and Higginson Halls
Parallel rows of these trees line High Street between Higginson and Nash Halls. They resemble the common beech (Fagus sylvatica) in shape and texture of bark. Their leaves distinguish the two, however: beech leaves are only very slightly serrate, whereas the leaves of Carpinus betulus are doubly serrate, with deeply recessed veins. In the autumn the distinction becomes even more obvious: beech trees produce a spiky nut-like fruit, whereas hornbeams reproduce by means of chains of small nuts, each attached to wing-like bracts (modified leaves) that facilitate dispersal in the wind.
The name hornbeam provides a clue to the nature of the wood of this species, which is native to a broad region of northern Europe and Asia Minor. The wood is extremely hard, dense, and - as firewood - is said to have a caloric value equivalent to coal. As a lumber tree it has been a bust, literally; attempting to mill it often results in broken tools. Formerly it was carefully fashioned into things like ax handles, ox yokes and wooden cog-wheels. Modern technology now allows it to be shaped into planks that are highly desired as decking, etc.
European hornbeam also is called musclewood, or ironwood (one of several species so designated). The former designation refers to the appearance of a mature trunk; smooth, gray and rippling, rather like the limbs of a body-builder, but without the oil and suntan. "Ironwood" refers to the hardness and density of the wood, which is quite exceptional. Some authorities claim that ironwood will not float in water, but with respect to the European hornbeam this seems to be incorrect. "Ironwood" is a name applied to several other species, however, and at least one of these (Olneya tesota, the desert ironwood) definitely will not float.
See Carpinus betulus on Wikipedia.