How Old Is The Bethnal Green Mulberry ?

The public hearing of our Judicial Review recommences at the High Court at 10:30am today, Thursday 6th May.

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Nurses dance round the ancient Bethnal Green Mulberry in the grounds of the London Chest Hospital, 1944 (Courtesy of the Royal London Hospital Archives)

This is a transcript of the Bethnal Green Mulberry lecture delivered at the Garden Museum in Lambeth by Julian Forbes Laird of Forbes Laird Arborcultural Consultancy. Julian is an expert witness in matters arborcultural and editor of the British Standard in tree conservation.

This lecture is in four parts. I am going to begin by looking briefly at the planning context. Then I will consider how old people think the Bethnal Green Mulberry is, before presenting the available evidence for dating it and offering a little bit of ancient history at the end.

1. THE PLANNING CONTEXT

Is it a Veteran Tree? And there are two definitions that might concern us. The most important is that from the National Planning Policy Framework. It references “trees which have great age, size or condition and potentially exceptional value for wildlife in the landscape or culturally.”  The British Standard for trees in relation to design, demolition and construction – for which I was a technical editor – has another definition,“trees that by a recognised criteria show features of biological, cultural or aesthetic value.”

The bible on this subject is by Dr Helen Read. She is the Ecologist for the Corporation of London and looks after number of very old collections of trees and individual trees as part of her work. Natural England published her book ‘Veteran Trees: A Guide to Good Management,’ in which she includes, ‘How to spot your Veteran Tree.’  The features she identifies are loose bark, dead wood, holes in branches and holes for wildlife. She also draws attention to trees which are large for their species, trees which have an old look, a pollard form which indicates historic management, and have known cultural or historic value. That the concept of a Veteran Tree promoted by Natural England.

Self-evidently, the Bethnal Green Mulberry ticks so many of the boxes that define a Veteran Tree that I think it is outside the range of professional opinion to say otherwise. The Bethnal Green Mulberry is a Veteran and the proposal to relocate it is unlikely to succeed. The tree will either fall apart or die, or possibly both.

2. HOW OLD IS THE BETHNAL GREEN MULBERRY?

Probably not as old as Stonehenge. Roman? No. Vikings? No. Tudor? It has been suggested that it is a Tudor tree. Bishop Bonner was a Tudor bishop of London, and the question is, “Is it his tree?” Certainly, many people believe it to be so. Conversely, is it a tree of about one hundred and fifty years old contemporary with the building of the London Chest Hospital? The latter two are the most likely suggestions.

In Crest Nicholson’s case, in the first planning application they provided a site investigation report. This identified the soil type to be plastic clay. Plastic clay is a type of soil. Unfortunately, it was read slightly differently by the archaeologists. Instead of reading plastic clay with glass and concrete inclusions it was clay with plastic, glass and concrete inclusions. The archaeologists decided this meant the soil was modern and therefore the tree sitting in the soil had to be modern as well. Which is credible if it had said plastic inclusions but it did not. It said plastic clay.

So the soil has fragments of glass and concrete and does that mean it is modern? Consider the Pantheon in Rome, it was built in AD125 and is still the world’s largest unreinforced concrete dome. The Romans knew how to make concrete. So glass and concrete in soil do not date that soil.

3. THE EVIDENCE FOR DATING THE BETHNAL GREEN MULBERRY

We are going to look now at the available evidence for dating the Bethnal Green Mulberry.

We are going to start by comparing the morphology of the Bethnal Green Mulberry in two photographs published below, one from the nineteen-thirties and the other from three years ago. In the photo from the thirties hospital fundraising pamphlet, you can see the stem of the tree goes off at an angle. Very clearly, there should have been another bit and that has gone.

If you look at the photo of the tree as it stands today, you will see precisely the same angle change. The missing branch was gone by 1930. This has a number of important implications. Firstly, the Bethnal Green Mulberry is patently much older than seventy-five years. Secondly, the failure of the crown only happens in mulberry trees after they are about one-hundred-and-twenty-years old. I have never seen a younger mulberry collapse. So when the Bethnal Green Mulberry suffered a crown failure prior to 1930, at the time of its failure it would be at least one hundred and twenty years years old.

Here we come to the famous inkwell preserved in the archive at the Royal London Hospital. A brass plaque notes that the inkwell’s base was cut in 1911 out of a broken bough from what was reputed to be Bonner’s Mulberry. If we take 1911 as the date when the bough fell off – although it could be before that – and you wind back one-hundred-and-twenty years, you get to around 1800. This is fifty years before the London Chest Hospital was built. In order to arrive at a planning-relevant judgement for the age of the Bethnal Green Mulberry, we need to understand how old it probably is. The youngest probable age of the Bethnal Green Mulberry is around 1800.

The other point to consider is that a tree planted as a sapling in the eighteen-fifties when the hospital was built was very unlikely to have sufficient stature to have had the legend of Bonner’s Mulberry attached to it. That legend would only be attached to the Bethnal Green Mulberry because it predated the hospital. So we have got the tree predating the Chest Hospital. When the hospital was built, the legend was already in place.

The Forestry Commission dating method produced by the Forestry Commission’s Research Dendrologist is a complicated series of calculations. Applying this method to the tree is fraught with difficulty because at the moment the tree only has about 680mm stem diameter. In the photographs, you can see there is quite a lot of the stem missing. So any measurement you make of the stem today is going to be a false record as to the maximum girth and therefore the likely age of the tree. At its peak, I estimate that the tree would probably have been about 800mm at its peak.

The Forestry Commission dating method also requires allowance be made for senescence. As trees age or suffer structural failures, they grow much more slowly. The minimum possible rate of growth of a tree is 0.5mm a year in its stem. A tree can only put on a fraction of growth over ten years and barely change its stem measurement.

If you start from what I believe to be a correct ballpark of 800mm stem diameter and you then allow that the Bethnal Green Mulberry has lost between fifty to one hundred years’ growth, this gives an estimate of three-hundred-and-fifty to four hundred years old for its age. This raises an interesting question – If it is too old to be planted by Bishop Bonner, where did the Bethnal Green Mulberry come from?

The Mulberry not a native British species and to propagate Mulberries in this country requires cuttings. You cannot grow them from seed. What this means is that the Mulberry which stands before us today could be a cutting of Bonner’s tree, preserving a cultural link.

There are three principal eras of introduction for Mulberries into this country. First, the Romans, secondly during Tudor times and thirdly King James’ introductions in the seventeenth century. If our tree is Bonner’s Mulberry, dating from the sixteenth century, it necessarily predates the King James’ introductions, so we can cross out number three. Therefore the chances are that it was a Tudor introduction, that is the most likely conclusion.

Yet there is another possibility which is a lot more fun, so now we are now going to delve into ancient history.

4. A HISTORY LESSON

Even before the Romans arrived, there were well established trade links between London and Colchester. The major obstacle to the movement of goods and services at the London end was the River Lea. In winter, the road heading out of London towards Colchester was often barred by the spreading Lea and the marshes of Hackney and Bow. The road immediately south of the former London Chest Hospital site is Old Ford Road which is the route to the old ford over the River Lea. In pre-Roman Britain, this would have been a necessary and important river crossing between the two trading centres.

When the Romans invaded Britain in AD43, they had to deal with the increasingly belligerent Catuvellauni who they had their tribal base in Colchester. The route of the invading army which came up from Kent into London would have taken them over the old fords of the Lea on their way to lay siege to Colchester. That was the only road. Later the Romans made a new road, still called Roman Road today, possibly because the old road was prone to flooding.

The Romans believed that Mulberries had beneficial effects on the gastro-intestinal system and a fair amount of of their writing about medical plant use has survived, recording this benefit. Mulberries were imported not simply because they thought they were pretty, they liked the shade or they liked the taste, but because they believed it was actually good for their troops to have it. They planted Mulberries at their military bases.

Let us consider the site of the former London Chest Hospital in Roman times.

It occupies relatively high ground compared to the marshes to the east, so it is a site which remained dry all year round. I would suggest that this was why it was subsequently occupied by the Bishop of London’s palaces. Higher ground permits a better view, high enough to get a good view of Old Ford Road around a hundred metres away. So you have a dry site with a good view of traffic on the road which makes it an obvious location for a Roman garrison outpost. The Illustrated London News recorded Roman tiles and bricks being discovered during the demolition of the Bishop’s Palace and the construction of the London Chest Hospital

Early in the fourth century, under Constantine the Great, the Roman Empire converted to Christianity which reached our shores around the same time. The Romans left Britain in 410AD but remains of their culture survived at least years after that. By the sixth century, the site of the former London Chest Hospital was owned by the early church. The name of ‘Bishopsgate’ in the London Wall reveals this as the portal by which the early bishops of London travelled to and from their seat at Bishop’s Hall.

The occupants inherited whatever the Romans left behind and the monks who attended the bishops were well known as herbalists. They read Latin texts about the medicinal uses of plants. This is why Mulberries are found in the physic gardens of monasteries and abbeys, because of their medicinal use. So if the Romans had planted Mulberries at the former London Chest Hospital site, they could have survived – their longevity is such – to span the gap between when the Romans left and the occupancy by the monks of the early church.

If you study the engraving of Bonner scourging a heretic from Foxe’s Book of Martyrs, there is a tree in the background, the Bethnal Green Mulberry of legend perhaps. This engraving was made in 1563, contemporaneous with the events it records. So there is no reason to doubt that Bishop Bonner had a Mulberry in his garden at the former London Chest Hospital site. The engraving shows a tree that could easily be a Mulberry. It could be something else but what reason is there to doubt it?  If someone were to make up that detail, it could be an oak tree or a lime tree.

So where did Bonner’s Mulberry come from? Was it a Tudor import or was it propagated from the scion of Roman stock, discovered in a weeded-over orchard by the first monks who inherited the site from the Romans? If the latter is the case, the Bethnal Green Mulberry could be a direct lineal descendant of a tree from the time of Constantine – a tree that preserves in its DNA the original import, a tree that bore ancestral fruit which fed the legions of Roman that watched over ancient London.

The Bethnal Green Mulberry, 1930 (Courtesy of the Royal London Hospital Archives)

The Bethnal Green Mulberry, spring 2015

Inkwell made in 1911 from a branch of the Bethnal Green Mulberry (Courtesy of the Royal London Hospital Archives)

This engraving of the completed London Chest Hospital published by the Illustrated London News on June 28th 1851 shows the fully-grown Mulberry tree to the left of the main building (Courtesy of Tower Hamlets Local History Library & Archives)

Illustration of Bishop Bonner scourging a heretic from Foxe’s Book of Martyrs, 1563

Graphic by Paul Bommer

Click here to read my feature in The Daily Telegraph about the scandal of the Bethnal Green Mulberry

Click here to read my feature in The Evening Standard about the scandal of the Bethnal Green Mulberry

Read more here about the Bethnal Green Mulberry

Here We Go Round The Bethnal Green Mulberry

A Plea For The Bethnal Green Mulberry

The Bethnal Green Mulberry

A Letter to Crest Nicholson

A Reply From Crest Nicholson

The Reckoning With Crest Nicholson

The Haggerston Mulberry

The Dalston Mulberry

The Whitechapel Mulberry

The Mile End Mulberry

The Stoke Newington Mulberry

The Spitalfields Mulberry

The Oldest Mulberry in Britain

Three Ancient Mulberry Trees

A Brief History of London Mulberries