How old are the oldest trees in the world

Hundred-year-old trees, thousand-year-old trees… We know for sure that trees live longer than we do, but how long do they live, how old are the oldest trees and when did they appear?

The oldest trees according to the different geological periods

The oldest trees in the Triassic period

Triassic seed fern: oldest trees

We have to go back to the Triassic period (250 to 200 million years ago), when the climate was hot and dry, to find the first trees.

The very first dinosaurs can be found here, and the plant kingdom is mainly composed of the Ginkgoaceae family (of which we know the Ginkgo biloba), conifers and seed ferns.

The outstanding Gingko biloba of the botanical garden of Tours

The oldest trees in the Jurassic

Millennium trees of the Jurassic

But this vegetation will especially take its place in the Jurassic (from 200 to 145 million years), where the arid climate of the Triassic evolves into a warm and humid climate, thus favoring the emergence of lush jungles. But contrary to what is often thought, dinosaurs did not wander among palm trees and plants with spectacular flowers! It was mostly conifers that dominated the flora.

Fossil of conifer in the Jurassic: brachyphyllum, the oldest trees
Wollemia nobilis, one of the oldest trees in the world

As previously mentioned, the Ginkgoaceae were dominant, of which the Ginkgo biloba has come down to us. But also the Araucariaceae family, of which we know the spectacular silhouette of the Araucaria columnaris that we meet in tropical gardens, a silhouette that can easily be described as prehistoric! Also part of this family, the Wollemi pine is just as spectacular and was recently rediscovered as still existing in Australia.

Araucaria araucana : oldest trees in the world
Remarkable millennium tree: the Cyca

And let’s not forget the ancestral family of the Cycadales of which the Cycas are a part! Halfway between a palm tree and a tree fern, their tough leaves with a spectacular silhouette are very sought after today.

Feuilles de cycas - Arbres les plus anciens du monde

Oldest trees in the Cretaceous

With a climate equivalent to that of the Jurassic period, the plant kingdom underwent a major evolution in the Cretaceous period (from 146 to 65 million years ago) and saw the appearance of Angiosperms, i.e. flowering plants. Diversified and abundant, they quickly colonized all the ecological niches that could accommodate them and quickly became the dominant plant group.

It is likely that these flowering plants had an influence on the dinosaurs, which began to feed on them (unlike the Araucarias and other Cycas with their more than dissuasive leaves!), and to develop an increasingly developed chewing apparatus.

These Angiosperms also favored the emergence of insects.
The oldest Angiosperm fossil found is the Archaefructus liaoningensis, now extinct, discovered in China, and resembling our black pepper.

Fossil of Angiosperm, the oldest plants in the world

Did the flora become extinct like the dinosaurs?

The disappearance of the dinosaurs

Fossile de Bennettitales : ordre de plantes les plus anciennes du monde disparu

Everyone knows of course the famous disappearance of the dinosaurs, with the different theories attached to this mass extinction. But what happened to the flora at that time is less known.

Volcanic eruptions, asteroid impacts, the sun’s rays were blocked by particles suspended in the atmosphere for many months, even years, preventing the possibility of photosynthesis of plants, drastically lowering the temperature on the ground and causing their death. The chain reactions were the death of herbivores, then of carnivores.

Thus some botanical orders became extinct at the end of the Cretaceous. The order of Bennettitales is an example: they resembled the Cycas, but they carried both male and female reproductive systems, which does not exist in the Cycas. A real fossil forest of these Bennettitales was discovered by the American paleobotanist Lester Frank Ward, whom the locals nicknamed “the Giant Pineapples of the Black Hills“.

The survivors

Here again, we know better the surviving fauna than the surviving flora. Some species such as lizards have been able to survive probably because of their small size and their need for less food, others such as crocodiles able to store large quantities of food, or the marine world such as turtles that consume organic matter suspended in the water and not the products of photosynthesis.

But the flora also has its resources! Because even if the plant dies, the seed can have a very long survival capacity. Seeds, spores, rhizomes, they are able to put themselves in dormancy and to support stoically unfavorable conditions while waiting for their environment to become again welcoming and favorable to the development of the plant. Thus, seeds of date palms dating from the 1st to the 4th century found near the Dead Sea have retained their germinative capacity, just like wheat several thousand years old found near Egyptian mummies, which could be put into culture.

In short, let’s save the plants, because they are the ones that can potentially save us from extinction!