Hornbeam

 

Hornbeam Carpinus betulus has always been one of my favourite trees. It's native to southern England but widely planted up here in the North East, often for its wonderful chrome yellow autumn foliage. It's known also for its hard timber, hard enough to blunt carpenters' chisels and saws and durable enough for traditional uses like wooden gear wheels for windmills and water mills, and teeth for rakes. Some say that the name hornbeam comes from the timber being as hard as animal horn.

Hornbeam is particularly beautiful in late autumn after most of the leaves have fallen, when the clusters of seeds still dangle like little pagodas from the twigs. Eventually the seed clusters break up and individual seeds fall and spin to earth on their winged bracts. The hard seeds, which are tiny nuts, are favourite food of hawfinches, so I always look for them at this time of year, though I've yet to see one of these spectacular rare birds here. I've only ever seen them in southern England.

The tree is also very attractive in spring, when it's covered in catkins and when the beautifully pleated leaves begin to unfold. 

A Tree-Spotter's Guide to Flowers: 2

Many trees produce their flowers in elongated catkins in spring, often before the foliage expands. Most - but not all - catkin-bearing trees are wind pollinated and produce vast quantities of pollen to ensure that pollination and seed set occurs. Hazel catkins are the most familiar ....

... along with alder catkins. Alder is usually the first tree to flower in spring.

Male catkins of hornbean are smaller than those of most other trees and produced just before the leaf buds open.

Silver birch male catkins are long and slender. The female catkin, seen here just above the leaves, is much smaller and points upwards. It will produce large quantities of seeds in winter, which are important food for finches.

Silver birch tree in full flower, in April.

There are separate male and female trees of goat willow (also known as sallow). This is the female catkin, with large numbers of stigmas. After pollination it'll produce masses of downy seed in early summer. Unlike all the other trees in this post, goat willow is pollinated by insects - flies, bees and butterflies - and both male and female trees are sometimes visited by blue tits that also have a liking for nectar - so this may be the only tree species in Britain that's pollinated by birds.

Male goat willow catkins, beginning to expand their golden stamens.

A male goat willow tree in full flower in late March can light up a hedgerow - and is an important source of nectar and pollen for the first insects that emerge in spring.

Poplar catkins are seldom seen (unless you go tree-spotting with binoculars) because they are produced right at the top of mature trees, but they are often the most attractive flowers of all the wind-pollinated species. They are much stouter that catkins of other trees. The best time to look for them is after a spring gale, when they are often broken off and litter the ground under the tree.

For more information about trees click here

A Tree-Spotter's Guide to Fruits and Seeds: Part 1

Surely the most gaudy tree in the British flora - spindle Euonymus europaeus. Spindle has been eradicated from hedgerows in some parts of the country because it acts as a winter host for the black bean aphids that infect field bean crops. That's a pity, because I can think of no other hedgerow  tree that presents such a colourful sight in autumn, when the leaves turn crimson and it produces these dangling shocking pink fruits that split open to reveal vivid orange seed. That soft orange outer layer is an aril - an extra seed coat layer that has evolved to attract birds that eat them and void the undigested hard seed seed through their gut. Arils are quite common in tropical fruits (the edible part of a lychee is an aril) but are uncommon in temperate floras.

Catkins of silver birch Betula pendula seeds ripen in late summer and begin to break up now - as these are doing - sending down showers of tiny winged seeds. Silver birch seed is a key food source for many finches in winter, including siskins and redpolls. The seeds can be produced in vast quantities - I was recently sent some samples to identify by a train company whose trains were breaking down because of overheating caused by engine air intakes becoming blocked by seeds from lineside birch trees. 

Indisputably a hawthorn - but which species? Common hawthorn Crataegus monogyna or Midland hawthorn C. laevigata? Now's the time to find out, by splitting open the fruit (which in botanical terns is a drupe, not a true berry). If there's one seed inside it's common hawthorn, if there are two then it's the midland hawthorn. This one had one-seeded fruits, so it's common hawthorn.

The powdery bloom on the outside of a sloe Prunus spinosa is a natural wild yeast that feeds on sugars that are produced in the fruit - although you'd be hard-pressed to detect any sweetness in the flesh of these incredibly bitter drupes. These two, and a couple of hundred others like them, are now bottled in gin in the cupboard under our stairs - and the resulting sloe gin should be ready for Christmas.

Hornbeam Carpinus betulus, famous for the hardness of its timber that was once used to make rake teeth and other similarly durable wooden items, bears these little pagodas of fruits that turn bright yellow with the foliage in autumn but remain on the tree for a while after the leaves drop, creating an effect a little like Christmas tree decorations. 

The hard seeds are nutlets, each attached to its own three-lobed bract that spins to the ground when it's released from the cluster.

For a Tree-Spotter's Guide to Buds, visit http://cabinetofcuriosities-greenfingers.blogspot.com/2009/11/tree-spotters-guide-to-buds-part-1.html

For more posts on tree ID click here