For still there are so many things that I have never seen:
in every wood in every spring there is a different green.
(from “I Sit and Think” by JRR Tolkien)
It’s that time again, for visiting “my” tree to give an update for Loose & Leafy’s tree-following project.
I feared I would miss the “female” flowers on the hornbeam, or not see them as the branches are so high up, so I picked one off from a much smaller hornbeam I pass on the street most days…
The hornbeam is apparently monoecious, meaning the male and female flowers are on the same tree. The males were the catkins we saw a month ago, so I suppose the gap in timing prevents the tree self-fertilising? Does that mean there won’t be any fruit if there aren’t any other hornbeams around providing later pollen? I’ve no idea.
You may recall that at first I thought “my” tree was a beech, so at the same time as I picked that sprig of hornbeam, I picked a couple of leaves from a beach hedge nearby, for comparison…
I don’t think the difference in colour is particularly relevant, it’s just that these beech leaves were younger than the hornbeam leaves.
Eventually I went to see the big old hornbeam again. April was all sunshine and showers, as you might expect in South Wales, and May has begun the same way. Wednesday was the only chance I had this week to go over to Llandaff Fields to visit and I was lucky there were breaks in the rain.
I had one particular task in mind this time, so I took along a ball of string and some scissors…
I thought I would try measuring the girth of the tree’s trunk to work out its age.
You are supposed to measure around chest height, and if the tree had been smaller I would have “hugged” it, but my arms wouldn’t reach even half-way around.
I was alone, but I had planned how to do this. I took the string and placed it on the ground around the trunk, then gathered the ends and brought them together, raising the string to chest height and tightening it a bit but without damaging all that lovely lichen and moss (I hope). I cut the string to the length of the circumference, although actually measuring it against a tape measure would have to wait until later.
Meanwhile here are some more pictures of my May visit…
Apparently young hornbeam leaves contain pheophorbide A, which is used in cancer treatments, as a photosensitiser in photodynamic therapy. Pheophorbide A is a chloropyll-related compound. No wonder green is the colour of life.
Under the hornbeam the Queen Anne’s lace (Anthriscus sylvestris), which I have always called cow parsley, is in flower, although the lesser celandine (Ranunculus ficaria) flowering season now seems to have ended.
Later I measured the piece of string against a tape measure – the circumference was 101 inches (256.5cm). In all the calculations I has seen of tree age, the diameter was needed, so I multiplied the girth by pi to get a diameter of 32 inches (81cm). All these figures are approximate, of course.
To work out the age, you multiply the diameter in inches by the “growth factor” of the species. But could I find the relevant factor for hornbeam? No.
Luckily my Googling eventually threw up my saviour – the wonderful Wokingham District Veteran Tree Association in Berkshire. The group identifies, protects and manages the significant old trees in the area. What a great idea!
By chance its definition of a veteran tree gave me the simple answer I needed. By its calculations, a veteran hornbeam has a girth of 2.5m. In good growing conditions, which I reckon mine has probably had, it would be a century old. It would have grown more slowly and been older for its size if it had been crowded in the middle of an avenue or a wood.
So there I have it, I think. The hornbeam, with a circumference of 2.565m, would be at least a century old and therefore a Victorian or Edwardian planting.