Christopher Berry

speaker

160 appearances 1 recordings 1 series first heard Jul 2026 last heard 2 Jul

Christopher Berry’s voice in public audio — every appearance, attributed to the second.

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Recordings per month over the last 12 months — 1 in all, peaking in Jul 2026 with 1.

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In Our Time · The Evolution of Trees · 2 Jul 2026 podcast

And for my very old trees, this tends to be the actual apex of the trunk.

So at the apex of the trunk, there's a thing called a meristem, which is producing new cells which become part of the trunk.

And in these ancient types of trees, then pretty much the whole...

body plan of the tree was organized from there so it would be give instructions as to where the branches would grow when they grow in geometric patterns coming back from the area um meristem problem with this is that that's extremely vulnerable because if you take out the meristem if you have frost or something of this big bulbous thing on the top of the the trunk then it can easily be destroyed and it's the same for the lycopod trees as well

I think Archaeopteris, the big, tall, woody tree that we see at Cairo in upstate New York, is a really interesting thing because with my PhD student Amy Wyatt, we've been in Spitsbergen collecting what we think are trunks of these Archaeopteris trees.

And up to a certain size, they seem to have very geometric insertion of the leafy branches that they had, which seems to fit in with this model.

It's all coming from the apex.

But work by American, particularly French colleagues, looking at the anatomy of some of these trees, shows that there's a new type of branching which can develop in Archaeopteryx.

And that's to say that it starts growing new branches from essentially the surface of the wood.

So it can produce a new branch anywhere on the trunk.

And that can grow into a big branch, a long-lived branch with fronds on it itself, or even into a new trunk.

So that sort of development gives the plant much more resilience because you can lop off the top.

You can have wind damage, other sorts of damage.

Another tree can fall down and take half of it away.

It could still grow.

So I think basically within Archaeopteris, at some point it changed from one type of branching

to the other and became more resilient and lasted for 25 million years as a genus.

And I think you can also add seeds to that.

If you add seeds to a plant, then it's also become more resilient.

For the trees, not totally sure, but seeds appear in the fossil record towards the end of the Devonian, but within shrubby plants rather than within trees.

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