Elm recording – a window of opportunity MAX COLEMAN
A Wych Elm (Ulmus glabra) tree in fruit in April (with a leafless Sycamore (Acer pseudoplatanus) on right of image. Max Coleman
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n 20 April, despite the national lockdown, I had a legitimate reason to travel between London and Edinburgh and I took the opportunity to spot elms from the train window as I went. This was not just idle high-speed botany as I had a purpose in mind. I have always been sceptical of the Wych Elm (Ulmus glabra) distribution map in the Atlas as it shows almost blanket coverage with a few gaps in the Scottish Highlands. It is not the gaps in the north that bother me. Rather, it is the absence of gaps in the south. In my experience Wych Elm is quite uncommon in many parts of southern Britain. There are, however, some notable exceptions on calcareous rocks; for example, the Yorkshire Dales. Anyway, as I was travelling at a time when all elms are easily spotted by their fruit clusters, I thought I would make a continuous observation to see if any patterns emerged. It is worth saying that elm fruits turn the trees green by their abundance, making them stand out against the other tree species that are still leafless. This time is a narrow window of opportunity for elm recording. The rail journey approximates to a north/south transect and this is useful as Wych Elm is said to
be more common in the north. The published hectad map by itself would give you the opposite impression. South of Newcastle I could see few elms in the trackside land or the discernible distance. Field Elm (U. minor) and hybrids (U. minor × U. glabra) are the taxa you would expect to find in the south. Field elms are not known to be good colonists via seed and the very widespread English Elm clone (U. minor ‘Atinia’, formerly U. procera) is known to be sterile. Nevertheless, some elms are present, and these tend to be of quite narrow habit, even as young trees. Although I cannot be certain at over 100 mph, I suspect these southern elms are Field Elms. In contrast, north of Newcastle elms become quite common and even abundant in suitable areas as you continue north. These elms look different to the southern elms as they are broad spreading from an early age. Coppicing of trackside trees is standard practice, and this does tend to encourage multiple stems and a broad habit. However, all trackside elms get the same treatment and the elms north of Newcastle do seem to have a broader habit of growth. Again, I cannot be certain, but my suspicion BSBI NEWS 148 | September 2021
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