Green islands in the fall of the leaf

The leaves are turning brown and falling. Fall is the traditional English name for Autumn, it’s not an Americanism. Spring was called ‘the spring of the leaf’ and fall was ‘the fall of the leaf’ in Britain. It was only after English speakers had set off to invade America that British people took the French word automne and began to use it as their own.

Plenty of leaves have fallen here. So have I, given the state of my trousers.

Being out in nature allows me to concentrate and relax at the same time. Nothing out here in the woods is of any consequence or causes any stress. I’m delighting in the sounds and smells of this tiny patch of woodland, caught between roads and towns. There’s a leaf which interests me. It’s a Beech leaf with two green islands in it:

The surrounding Beech trees have been very careful to withdraw all the movable nutrients they can from their leaves. Anything complex that can be liquified and transported is saved because, to coin a phrase, ‘Winter is coming’.

What has gone wrong here? Look carefully and you can see two very small holes or growths near the vein where each green island starts. An insect has laid two eggs in this leaf and those insects have caused disruption to the natural seasonal chemical withering of the leaf. The leaf is still fresh and green where the insect will mine inside the leaf, tunnelling from the inner vein to the outside of the leaf in a zig-zag pattern, in a tunnel getting wider and wider as it grows. It’s kept its own food store fresh and green and rich in nutrients while the rest has withered and dried.

It might be micro-moths living in this leaf. It also might be bacteria brought by the egg-laying adult which cause the disruption to the tree’s hormones. How cool is that? Bacterial endosymbionts manipulating plant physiology. Whatever it is, it’s an entire miracle of nature in a single leaf in the woods.

Nature. It’s very absorbing.