A resilient tree
Nature is truly remarkable! Some trees have developed spectacular defences to survive in hostile environments.
The Araucaria (Araucaria araucana) – native to the Andes – is instantly recognisable thanks to its branches covered in rigid, prickly scales. These overlapping leaves form a natural armour against herbivores, but also a perfect adaptation to the extreme conditions of the Andean mountains: intense cold, drought and strong winds. Its lineage dates back over 200 million years, and some individuals live for more than 1,000 years. Its very thick bark even allows it to survive fires.
The honey locust (Gleditsia triacanthos) – native to North America – also relies on intimidation: its sturdy thorns, often grouped in threes – hence its Latin name triacanthos – can exceed 20 centimetres in length. They adorn both the trunk and the branches, forming a formidable barrier. Some scientists believe that these giant thorns were originally a defence against large herbivores that are now extinct. Despite its menacing appearance, it is remarkably tolerant of poor, dry soils, as well as urban pollution. Generally, thornless varieties of honey locust, such as Gleditsia triacanthos ‘Inermis’, are found in towns and cities. In Latin, ‘inermis’ means ‘unarmed’.
The ginkgo (Ginkgo biloba) – native to China – is also a survivor from prehistoric times. Having first appeared over 200 million years ago, it is one of the oldest trees on the planet. Its resilience is legendary: it is resistant to disease, insects, pollution… and even, it is said, to nuclear disasters. In autumn, its foliage takes on a brilliant golden hue that lights up the streets. Introduced to Europe in the mid-18th century, it is a dioecious species, with separate male and female trees. The female ginkgo produces ovules that resemble mirabelle plums when ripe—a seed surrounded by a yellowish pulp—but which give off a very unpleasant smell when crushed.
As the ginkgo has not developed a shell to protect its seed, this repellent odour deters many animals and insects from consuming the seed before it is ripe. This is one of the ways in which the species ensures its survival.
The seeds contained within the ovules are nonetheless tasty, whether roasted or boiled. They are highly prized in Asia, where they are used in particular at weddings, as the ginkgo also has a symbolic and sacred role in this part of the world.
Did you know? The araucaria is nicknamed the ‘Monkey’s Puzzle’ — because even an agile primate wouldn’t dare to climb its spiky branches! When the English discovered the araucaria, they called it the ‘Monkey Puzzle’ to refer to the difficulty a monkey would have in finding a way to climb this tree. Historically, the Ginkgo biloba is said to have survived the atomic bomb dropped on Hiroshima in 1945: although severely damaged by the explosion, some trees began to regrow as early as the following year. Finally, musically speaking, the fruits of the American hackberry are long, twisted pods of a brownish-purple colour, measuring several dozen centimetres in length, containing dozens of seeds resembling coffee beans. These wavy-shaped pods fall to the ground in winter and can make music if shaken with your hands. It’s easy to see why some people call the American honey locust the ‘maraca tree’!
