There are nine species of baobab tree, seven of them found in Madagascar (mostly in its drier parts) and six of them endemic to the island. The common African baobab (Adansonia digitata) has spread widely across the island and its huge bulk makes it unmistakeable, but it’s the profusion of baobabs confined only to Madagascar that makes the group so fascinating.
The genus is named after the French explorer Michel Adanson, who remarked from the banks of the Senegal River in 1754: “I perceived a tree of prodigious thickness, the like of which I do not believe was ever seen in any part of the world”. There are several well-known myths attached to baobabs, all of them variations on the idea that God grew tired of this disruptive tree that wouldn’t stay planted and marched around the countryside, so he replanted it head first, with its roots poking into the air. These charming stories are however outdone by the fascinating natural history of the trees.
For baobabs, environment is all: in well-watered areas they grow tall, but they remain stunted in the harsh tsingy zones where a 3m specimen may be 100 years old. Even in the best conditions, they are notoriously slow growers, taking decades to reach a good size, and prone as tasty saplings to be eaten by zebu or goats before ever fruiting. Once established, however, they’re very robust, with their thick, pulpy flesh almost immune to the bush fires that consume so many other species, leaving the baobabs standing when the rest of the forest is long gone. That said, without having specialist knowledge, they can be quite hard to identify, especially when standing alone.
Madagascar’s baobabs are in leaf between the start of the rains, usually in November, and April or May when the dry season begins. Four of the species – the tall, straight Adansonia za and much smaller A. rubrostipa (both from the west), the more northern, multi-shaped A. madagascariensis and the moisture-loving A. perrieri from Montagne d’Ambre – flower during the rains, producing huge, fleshy blooms. The flowers open at dusk and are mostly pollinated by Madagascar’s giant hawk moths, whose nectar-sucking tongue can be more than 20cm long. The localized Adansonia suarezensis in the far north, and the west’s giant Adansonia grandidieri (the baobabs at the Allée des Baobabs) flower in the dry season and are pollinated by various species of bats, as well as fork-marked lemurs (Phaner). Strangely, although the sherbet-like pulp of baobab fruit is good to eat, there are no living animals that do so, leading botanists to speculate that the job of seed dispersal might have been done by an extinct giant lemur (such as Archaeolemur, which died out around 1200 AD).
Which leaves the baobabs of today relying on humans to disperse their seeds – and protect the vulnerable seedlings. Although baobabs can live for hundreds of years, they don’t have tree rings, so a baobab’s age is hard to measure, but most botanists think the six endemic species will die out in the wild unless huge efforts are made to protect them. Their commercial value may come to the rescue: as well as the bark being used for rope, the fibre as a water source and for thatch, the fruit, seeds and even the leaves are edible. Indeed the very high vitamin C content of baobab fruit has made the dried and powdered fruit a popular dietary supplement. And Homeopharma, Madagascar’s national chain of homeopathy and herbal remedy stores, sells baobab seed oil that people swear by as a skin rejuvenator.