The World’s Most Poisonous Tree: The Manchineel Tree
By: Danny Kane
Tags: Food, Agriculture, Health, Climate Change, Environment

The World’s Most Poisonous Tree: The Manchineel Tree

The Little Apple of Death

A warning sign near Manchineel trees (-JvL- from Netherlands / CC BY 2.0)

Across the coast and wetlands of the Americas, the Manchineel tree has come to be known as the world’s most deadly tree.

The tree is so poisonous that simply touching its bark can cause serve rashes. Getting rainwater that’s touched the tree in your eyes can lead to temporary blindness, as can the smoke from burning the wood of the tree. The sap will also cause serve rashes, but it’s the fruits that have become infamous the world over. Eating one of the small apples from the Manchineel tree will cause tremendous pain and swelling in the throat, and for some unlucky individuals this can lead to death by asphyxiation.

However, resourceful humans have found a use for this deadly tree, both to hurt and to heal.

History of the Manchineel Tree

The tree was likely known to the native peoples of the Americas for centuries, but with practically no records from these peoples, it’s impossible to confirm for what length of time, and how, they made use of it. The first time the tree enters the historical record for our purposes is in the late 15th and early 16th centuries with the arrival of the Spanish conquistadors.

It’s not known who exactly named the tree, but it’s thought to come from both the Spanish ‘manzanillia’ and the French ‘manchinille’ both of which refers to a type of apple. The Spanish would give the fruit a more appropriate epithet, however, calling it ‘manazanita de la murete’ or ‘little apple of death’.

It’s also from the Spanish conquistadors that get our first glimpse into one of the trees’ primary uses at this time — warfare. The Carib Indians of South America (from whom the English word ‘cannibal’ is derived, as well as the word ‘Caribbean’) are said to have dipped their arrows in the sap of the Manchineel tree, while also using it to poison water supplies in an attempt to hamper the Spanish advance. Early conquistadors learned to avoid eating the fruits of the trees, yet still suffered its poisonous effect in clashes with the Carib Indians.

The Poisons

The Little Apples of Death

What exactly makes the Manchineel so poisonous is not fully understood. A great many plants evolve toxicity to deter predators, but the Manchineel is an outlier in just how extremely toxic it is.

Aside from humans, the tree is also toxic to most animals and birds, with rare exceptions. The striped iguana of Central and South America is known to eat its fruits, and even live in the trees on occasion. Again, why they can tolerate the toxicity isn’t fully understood.

Its proximity to the oceans has been put forward as one reason for its toxicity, since it can disperse seeds via the ocean, it has little need of the birds or animals to ensure its survival. This is just one theory, however, and the debate continues to rage. Scientists aren’t even sure which chemicals make the tree so toxic. Hippomanin A and B have been identified, but many others remain a mystery.

Uses for the Manchineel

It may come as no surprise, given the seemingly unending toxicity of the Manchineel tree, that numerous culling’s over the decades have seen this tree slowly move into the category of ‘endangered’.

While it may sound like a good thing to rid the Americas of this deadly scourge, nothing is ever that simple. Typically growing in dense thickets in coastal and swampy regions, the tree provides an important bulwark in soil and beach erosion. Each year, in the United States alone, the nation’s beaches recede between 25ft (7.6m) and 50ft (15.2m). Coastal erosion costs around $500 million annually in coastal property loss, with an additional $150 million being spent on combating coastal erosion each year. In addition to all this, 80,000 acres of coastal wetlands are lost each year to erosion.

In both of these situations, however, the Manchineel tree can help. It’s deep roots and denseness make it well suited to lessening the effects of erosion, while also providing a natural, low maintenance windbreaker. And that’s to say nothing of the small, safe ecosystems they create for the few animals that can live in them.

Beyond ecological benefits, the Manchineel tree has long been used for furniture wood in the Caribbean. While it may seem a strange choice to make furniture of a toxic tree, they can grow to be almost 50ft (15.2m) and can provide ample wood in places where such resources are scarce. However, the wood does need to be dried for days in the sun to render the sap harmless, before it can be used in furniture construction.

Valuable wood from the Manchineel tree (Skimel / CC BY-SA 4.0)

In native traditions, such as those of the Carib Indians, gum from the tree was also used as a diuretic and an oedema remedy, proving yet again that our capacity to turn the same substance into something to heal or hurt with is by no means a modern one.

Today, Manchineel trees are emblazoned with warnings against disturbing them but could be vital in the defence against a changing climate. However, further weakening to environmental protection laws within the US is putting these already endangered trees under a new threat.

While it may seem strange for us to focus our efforts on saving something so aggressively poisonous just touching it can cause problems, it’s important to remember that each plant or animal is vital to its ecosystem, whether we like it or not. Though we often forget it, humans, like Manchineel trees are simply one part of a wider world.