Has anybody else noticed the masses of sycamore seedlings this year?

Last year was a hot, dry summer – sycamore trees liked this and produced a lot of seeds. This is called a “mast year” when a tree produces a lot of seed, and is often in some sort of cycle. The winter has then been relatively wet and cold (but not too cold). This promotes germination in the sycamore seedlings.

The result? Tons and tons of sycamore seedlings this year! Here they are growing up through cracks in the drive and cracks in the pavement. These trees will, of course, never reach maturity – either the human weeder comes along, or the street sweeper. Sycamores are big trees, up to 35m high, and belong in a wood or a park. They are also not considered native to the UK as they were probably introduced by Romans. Native tree species are the ones that were here as the ice age glaciers melted and before Britain was disconnected from Europe, around 9,700 BCE to 6,500 BCE.

However, the sycamore seedlings can also be poisonous to horses – eaten whilst grazing. Neurotoxins in the seeds can attack the horse’s nervous system, causing myopathy. This means that their muscles are affected. If they haven’t eaten too many, they might pull through after a day or two. But otherwise even their breathing muscles stop.

As soon as the weather warms up, the second leaves on these seedlings will appear and make these unmistakable! Meanwhile those seedlings in woods or parks might stand a chance of growing up, filling spaces left either by ash disease or storm Arwen. (Although native species probably belong better in our ecosystems!) Sycamores can live for 400 years and mature trees are extremely tolerant of wind and pollution. Aphids like them, therefore so do ladybirds, hoverflies, birds and moths.