Heartwood

Regular readers of this blog will know I an passionate about trees; from the gnarly old apple on the communal green outside my cottage flat, to the larches that bear tiny cones in winter, and the purple tinted alders that mark the river’s bank. Britain’s native trees include 32 different species, but each has its own story to tell. The most famous of our trees of course, that which is often held synonymous with England, is the Oak. We actually have two species of oak native to the UK, Pedunculate and Sessile oak, and you can find a handy guide to which your local oak trees are, here on the Woodland Trust’s website.

The oak commonly referred to as ‘English Oak’, is the pedunculate variety; ‘Quercus robur‘. The history of this tree species in the UK is deep and entrenched in our culture and identity.

Stuff of legends

The oak’s vitality, longevity, and prevalence in our countryside and culture, has earned it a strong foothold in folklore and fairytale. Robin Hood and his Merry Men may have made their outlaw home amongst the oaks of Sherwood Forest, but our relationship with the oak goes back much further into the mists of time.

The word Druid may derive from a Celtic word meaning “knower of the oak tree” and the tree held a prominent place in pre-christian beliefs. The oak leaf is a common motif found in carvings and church architecture to this day. The deep rooted ‘green-man’ iconography is often adorned with oak leaves and acorns.

And of course, in 1651 it was the oak hid the young royal Charles II from Oliver Cromell’s men at the time of the English Civil War. Perhaps one reason why ‘The Royal Oak’ continues to be the second most common pub name in England!

Hewn from timber

From rib-beams of ships to wine barrels, church pews to leather staining tannins, even acorn flour, oak has been a source of valuable material supporting human activity throughout our history.

A land rich in oak forests was a vital resource for medieval kings intent on building vast navies or impressive cathedrals. Many of our mature oaks of the 16th-18th centuries were felled to provide the strong beams and planks needed for ship building. The importance of the oak to the dominance of the high seas sort by Britain at that time, is reflected in the Royal Navy’s official march “Heart of Oak”.
Meanwhile, in the New Forest and other areas where commoner’s rights permitted grazing of livestock, acorns were an important foodstuff for pigs, which were let out onto the forest in the autumn for forage, in a practice known as pannage.
The tannin chemicals found in oak bark have been used as a dye stuff, particularly in the treatment and working of leather, since Romans times. Oak apples (see gall wasps mentioned later in this blogpost) also can be used to produce a dark black dye used as ink.

A Wild Life

Mature trees and woodland edges are the habitat of the tawny owl. This is the owl that makes that classic ‘twit-twoo’ calls we know so well.

It is claimed, that over 2300 different species can be associated with Oak trees, possibly more than any other uk tree species, and that figure climbs dramatically when fungi, bacteria and other micro-organisms are counted too! Considering that a single oak tree can live for hundreds of years, and a veteran tree can include countless microhabitats (from leafy growth the feed and shelter caterpillars, to rot holes in its trunk, to crevices and leaf-litter around its roots) it is easy to see why the oak is such a wildlife magnet. Among the thousands of creatures that inhabit and visit oak leaves, there are a few key species that rely on the oak tree for some or all of their lifecyle.

Jay
The jay is a member of the crow family, but unlike its cousins, its black feathers have been replaced by pinks, beiges, flashes of white and a glint of blue. It is also a secretive, although vocal, bird of woodlands. You are most likely to see a jay in the autumn, when they are conspicuous and noisy – fighting over acorns in oak woodlands and flying out across fields to bury and cache their nutty prize. In fact, jays bury so many acorns every autumn, that they can’t possibly remember where they all are, so it is quite likely that an oak tree near you was planted by a jay!

Purple Hairstreak butterfly
Spend some time peering at the top of an oak tree with a pair of binoculars in high summer, and you might spot the flickering flight of a butterfly in the canopy. Even a solitary oak tree may support a colony of purple hairstreaks. This pretty butterfly is easy to miss; small and dark, living their lives in the high tops of large oak trees, it is easy to see why they are so often overlooked! The adult butterflies fly in July and August, and are most active late afternoon and evening on warm sunny days.


Stag beetles are the uk’s largest insect and an impressive but harmless beast. Now a rare and threatened species, the beetles need rotting tree stumps for their larval stage, where they can spend up to 7 years underground eating the softened wood!

Oak Apple Gall Wasp (Biorhiza pallida)
Not all wasps carry the classic yellow stripes and painful sting of the sugar-loving picnic-botherer. Oak trees alone support 70 different species of tiny gall wasps; small solitary wasp species which create galls or small deformities/growths on leaves or stems of the tree, in which their larvae develop. The Oak Apple gall wasp is responsible for distinctive brown ‘marbles’ on the twigs of oak trees in summer, which often persist as hard shells long after the new generation of wasps has emerged and can be easily seen still on the tree after leaf drop in autumn.

Threats

There are threats to the oak; our national tree is not immune to pest and disease. Acute oak decline is a worrying tree disease which is spreading across the country, characterised by oozing splits in the bark, and potentially killing a mature tree within 4-6 years. Another threat is Oak Processsionary Moth, an invasive and introduced species which produces hordes of caterpillars which travel in army-like columns from tree to tree, causing significant damage and defoliation. The caterpillars also have a coat of irritating hairs which can cause discomfort and allergic reactions in humans. The Oak Processsionary Moth is a notifiable species, meaning their presence in the UK is being monitored and tracked. Andy sightings should be recorded. You can find out more here: https://www.forestresearch.gov.uk/tools-and-resources/pest-and-disease-resources/oak-processionary-moth-thaumetopoea-processionea/
If you are buying or planting timber or trees, check for the FSC mark on the timber, or source plants grown in the UK, to help protect our existing populations of oak trees from imported pests and diseases, and never bring plants, seeds or soil home in luggage from holidays abroad.

So if you are celebrating the lifting of Covid-restrictions this summer with a long awaited pint in a country pub garden, sit back and look up at that mighty tree on the pub sign or standing proudly by the garden wall. It has been there long before us, and with a bit of luck, will stay standing and shading beer drinkers and feeding caterpillars for a century or two after we are gone. Isn’t that something quite marvelous?

The title of this blog post is inspired by a poem and musical piece ‘Heartwood’ by Karine Polwart and Seckou Keita, which was written and shared/published as part of The Lost Words Spell Songs project. It is a beautiful and moving piece, and the perfect note on which to leave you. As always, thank you for reading my blogs, feedback and comments are always welcome, and I hope you enjoyed it.

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