Meet the world’s first tree (it was kind of a mess)

Explore a realistic image of a Devonian forest, showcasing the early forms of trees and plant life that characterized this period of the Paleozoic Era.

Have you ever wondered what the very first trees on Earth looked like?

Let me tell you all about them.

A recent discovery (and a bit of a personal saga)

During a recent afternoon, while I was doing my daily Instagram check, I stumbled upon a post about the world’s earliest trees. My curiosity was so piqued that I fell down the rabbit hole of researching them.

As I began learning, I found myself drowning in moments of confusion (and near madness) due to the sheer volume of scattered information online. Most of the time—practically always—the facts are so fragmented that you’ve no idea where to start, especially when tackling something as monumental as the origins of our forests. I even had to channel my inner university student again, dusting off my research skills so we could explore this mind-blowing, underappreciated topic together. (Do let me know if you’ve ever pondered what Earth’s first trees were like, by the way!)

Right, let’s dive into what I’ve learned—so you can learn too!

The first trees emerged around 419–359 million years ago, during the Devonian period. These organisms revolutionised ancient terrestrial ecosystems, developing the earliest woody structures and complex root systems!

THE PIONEERS: Cladoxylopsids and Archaeopteris

First off, a disclaimer: new discoveries and research emerge every decade, so we can’t definitively claim these as the only “first trees”.

Fossil evidence suggests these early trees weren’t identical to modern ones (obviously). With that in mind, here’s what we know so far:

1) Cladoxylopsida

• First appeared in the Middle Devonian, roughly 393 million years ago.

• Reached heights of 8–10 metres.

• Key genera: Wattieza, Pseudosporochnus, and Eospermatopteris.

• Dominated ecosystems before modern forests evolved.

• Thrived in swampy areas and riverbanks.

• Their anatomy was fragile compared to modern trees, yet they proved it was possible to grow tall on dry land.

• Vanished by the end of the Devonian.

Peter Giesen’s research unveils the striking structure of Cladoxylopsida, Earth’s earliest known tree. Unlike modern trees, this prehistoric giant lacked true wood and roots. Instead, its hollow, vertical stems resembled interconnected tubes, topped with fern-like fronds. Giesen’s fossil analysis suggests a fractal-like branching pattern, supporting a lightweight yet towering form (up to 10 meters tall) in swampy Devonian landscapes.

Fossils of Wattieza—currently dubbed the “world’s first tree”—have been found in New York, Belgium, and Venezuela. One 8–10-metre fossil was uncovered by palaeontologists in Schoharie County (Mohawk Valley), New York (Berry and Casas, 2024). Based on its modular structure, Wattieza likely shed massive amounts of dead leaves and branches. This littered the ground with organic matter, storing carbon and creating habitats for Devonian fauna that fed on the debris (Stein, Mannolini, VanAller Hernick, Landing, and Berry, 2007).

This image displays a fossil of Wattieza, a significant member of the Cladoxylopsida and often referred to as the "world's first tree." This fossil reveals the early branching architecture of these pioneering plants from the Middle Devonian period (around 393 million years ago). The preserved structure provides crucial insights into the anatomy and growth patterns of the earliest trees and their role in shaping ancient terrestrial ecosystems.

Wattieza was also the tallest tree of its time. It reproduced via spores, which its height helped disperse efficiently across ecosystems. They likely inhabited warm-temperate zones, such as the ancient continent Laurentia. According to Berry and Casas (2024), its fern-like structure represents the oldest documented example of an evolutionary “tree design” in vascular plants.

Essentially, Cladoxylopsida trees like Wattieza laid the groundwork for modern trees. Think of them as an “evolutionary experiment”. Fossils from Gilboa, New York, revealed that the oldest known forest was dominated by Eospermatopteris, a member of this group (Cladoxylopsida).

These early trees resembled modern palms. Their trunks weren’t solid pillars but hollow cylinders lined with xylem columns, bound by a network of fibres. Soft tissue between the fibres expanded like foam, pushing the trunk outward to gain girth and height. Brutally, each expansion split the xylem skeleton, forcing the tree to repeatedly heal itself. Ultimately, its own weight became its downfall, flattening the base like a deflated balloon.

While Cladoxylopsida were evolutionary trailblazers, Normile (2017) notes they’ve no living descendants. They were eventually outcompeted by sturdier trees like Archaeopteris.

2) Archaeopteris

• Emerged in the Late Devonian, ~385 million years ago.

• A direct ancestor of modern trees.

• Fossils found in Cairo Quarry (New York) and Morocco.

• Notable species: Archaeopteris halliana, A. macilenta, A. obtusa.

• Grew up to 25–30 metres tall.

• The first tree with abundant flat leaves.

Many consider Archaeopteris the first “true” tree with modern traits: deep roots, flat leaves, and a woody trunk. Remarkably, it could “resurrect” itself—if its main stem died, it could regrow, a trait later seen in seed plants.

Illustration of Archaeopteris, an early fossil tree with a tall trunk and fern-like foliage.

Oddly, this ancient tree shared features with both modern trees and ferns. It dominated landscapes like an oak but reproduced via spores, not seeds. Its efficient use of space fuelled its ecological success, explaining its global dominance in Late Devonian floodplains (Meyer-Berthaud, Scheckler, and Wendt, 1999).

As Stein et al. (2007) highlight, Archaeopteris leaves weren’t just novel—their design maximised photosynthesis with minimal biomass, outperforming simpler plants. Combined with deep roots, this created an “evolutionary toolkit” that supercharged its physiology (from energy capture to resource management). This likely explains why Archaeopteris ruled Devonian ecosystems and laid the foundation for modern forests.

Finally, here’s a kicker: Archaeopteris forests (comprising 90% of woodlands in the Late Devonian’s final 15 million years) boosted Earth’s atmospheric oxygen from 5% to 20%. Their leaves also fed freshwater streams, driving the evolution of fish and reshaping marine ecosystems. As the first organism with extensive root networks, it permanently altered soil biogeochemical cycles. These changes redefined ecosystems forever—a true evolutionary milestone!

When Archaeopteris vanished, forests retreated to humid tropical zones, giving rise to lush green jungles and ushering in the Carboniferous period (359–299 million years ago).

Ginkgo biloba, a “living fossil” from the Permian era (270 million years ago), bridges ancient and modern forests. Unlike fragile Cladoxylopsids, Ginkgo evolved sturdy trunks and tough, protective seeds, surviving asteroids, ice ages, and urban sprawl. Building on Archaeopteris’ innovations—like deep roots and flat leaves—it thrived as an early gymnosperm. Today, Ginkgos flourish globally, their biology nearly unchanged. When their golden leaves fall each autumn, they echo Earth’s botanical dawn, proving evolution’s “messy experiments” can craft survivors that outlast continents.

It’s easy to think of forests as timeless — always there, always green. But even they had a beginning. A messy, magnificent, miraculous beginning.

And next time you walk through a woodland or lie under a tree’s shade, just remember: you’re sharing space with an idea that took hundreds of millions of years to get right. And it all started with a few bold plants reaching for the sky.