5 Oct 2020

Tree Diaries

Bruce Langridge

For over 20 years I’ve been making a note of when I saw my first leaf of whatever British native tree I come across.

This had no particular purpose other than I’m one of those botany geeks who enjoys making lists to see how seasons vary from year to year. It wasn’t too scientific but it really made me look and get excited when this or that tree came into leaf really early or really late.

Phenology. That’s the word used to monitor seasonal changes like this. Last year it inspired our nature conservation volunteers to monitor the leaf burst of 15 native trees around the Botanic Garden. But not just the leaf burst. They’re looking at leaf bud development, the emergence dates of tree flowers and their transformation into fruit, then the fall of leaves.  Then there’re sightings of birds and bugs on the tree, the changes to ground flora around the tree, fungi that could either harm or help the tree, and the emergence of new branches that might start shading out rare lichen.

Our tree volunteers, led by former teacher Marie Evans, have also been inspired to make drawings of the trees and their seeds, to compose poems and to neatly handwrite all their observations into what may be called scrapbooks but really, are beautifully made books that Marie bought from an art gallery.

The 2019 book is nearly completed now – it just requires the sticking in of photos of all the volunteers who took part – over twenty and counting. When completed, this, and its 2020 version and hopefully 2021, 2022 etc versions, will all end up in the Botanic Garden’s Library and Archive where we hope, future researchers will find a wealth of observations which will help to show how what may then be grand old trees had adapted to changes in climate, management and use. Sadly, one of the 16 featured trees is unlikely to make it that far – the ash tree on our Millennium Lawn has, this year, shown a dramatic deuteriation as it fights the impact of the ash dieback disease that is having a devastating effect on all of our native ash trees across Wales, the UK and Europe.

But let’s not end on a sad note. I’m really looking forward to see how regularly our two featured oak trees produce acorns, the beech trees beechmasts and the hazel cobnuts. Will fly agaric fungi fruit under the birch after we spread its spores there, will we ever see a bumper crop of wild pears and when will we see our first bird eggs hatched in one of our trees? Does the lime tree smell so beautiful at the same time every year? What are all those lichen on the sycamore? Covid deprived us of the volunteer help of an expert bryologist (mosses and liverworts) this year, but we hope that she, and other experts, will help us to record and monitor the more obscure species over the next few years, or even help us date each tree.

Let me know if you can bring any expert knowledge to help Marie and the team.