Uncovering an arboretum’s forgotten past

This year there has been a new sound in the arboretum. Amongst the usual bird song and leaves swaying in the breeze there has been an occasional bleep. An unnatural but very persistent bleep.

Since we began mapping the arboretum in 2019, we have started the slow process of filling in the blanks – the hundreds of unknown trees in the collection. We have labelled and identified a few key specimens but there is still much to do. The majority of the labels we have inherited are plastic, with faded writing which proves very difficult to read, if readable at all.

There was one glimpse of the past though, in an old label at the foot of a Caucasian wingnut tree. The label is made of metal and driven into the ground, we had often admired it but assumed all others of its type must have been lost – or taken by visiting soldiers during the second world war, as the local tale goes.

When a volunteer with our Tuesday management team asked if he could bring his metal detector and have a look around for artefacts, we thought it a fun idea but didn’t expect very much to be found. There were lots of finds straight away, mostly foil lids and tent pegs, then a coin or two turned up.

One day our volunteer then had a brilliant idea – what if he scans the old plaque, then uses its signal to narrow down the sensor’s range, cutting out other types of metal. We thought it far-fetched but worth a try, maybe more exist?

In a quite surreal moment, it was instantly successful – after a few minutes of looking at the base of the nearest trees, our first lost label was found! It was for an Aesculus indica. We were delighted and the search began for more.

Our findings so far

Since the initial discovery, there has been lots of activity. The labels found have mostly been in our main area, alongside the largest trees. The plaques have ranged from being a foot underground to being tantalisingly just under the surface. It’s amazing to think they have been there all this time, and to wonder how many others are still waiting to be found.

Sometimes they provide a definitive ID for a tree, whilst other times offer more questions than answers, for example finding a Quercus mongolica sign deep under the roots of a Quercus alba tree. Has the oak been misidentified or the label randomly discarded there? Another label for ‘Quercus Olivaeformi’ (misspelling of oliviformis?) was found under a large conifer, so perhaps we shouldn’t assume too much from their positions.

There were also some interesting conversations around the naming on the labels e.g. ‘carya’ comes from the ancient greek meaning nut and is combined with ‘amara’ meaning bitter (in Carya amara, the old name for a bitternut hickory) and also combined with ‘pteron’ meaning wing (as in Pterocarya, the genus for wingnuts).

The labels

So far we have found three different types of plaques, some rectangular, some oval and one of a lighter type, made from softer metal. There is also a makers mark on them for J. Smith in Stratford on Avon, Royal Label Factory. It turns out another nearby arboretum also used the same supplier; the Tree Team at Westonbirt have also uncovered some similar labels.

More information on the labels here:



A tree we had previously identified – wonderful to have its ID formally confirmed!

What’s next

We are in the process of working through the site, prioritising some of our oldest and largest trees, as well as those that don’t currently have an ID. With luck we will find a few more clues!

We’d be interested to hear if any other collections have experimented with using metal detectors to find treasures from the past – please do get in contact if you know of this being done elsewhere.