Studies involving life on earth is a continuous process and enriches the incredible and arduous work already conducted by naturalists down the years. They had no computers and were unable to digitise their findings. They traversed the darkest depths of Africa and South America, collected specimens of plants, which they painstakingly preserved between pages of books, then returned back to list and identify their collections. Species of different forms of marine life, animals, birds and insects were dissected, sketches drawn, to finally become sections of many registers.

Alexander von Humboldt (1769- 1859) wrote several books and one, entitled, Personal Narrative, inspired Charles Darwin (1809-1882) when he joined Captain Fitzroy on the HMS Beagle to circumnavigate the globe.

Throughout the Beagle’s voyage, Darwin was engaged in an inner dialogue with Humboldt, where with a pencil he highlighted Humboldt’s narrations that coincided with his own experiences.

Later when Darwin saw the Chilean plains after days of exploring the “untamed forest,” his thoughts were echoed by Humboldt’s writing, “New sensations and the delight of being able to ‘see’ again after weeks in the dense rainforest.” Darwin described the same rainforest as “the wilderness of trees”.

When Humboldt experienced an earthquake in Cumana, in 1799, he wrote “In an instant it was sufficient to destroy long illusions,” which again echoed Darwin’s thoughts — which he recorded in his journal — of an experience of an earthquake on the coast of Tierra del Fuego, “It can destroy the oldest of associations.”

Both Humboldt and Darwin had an unusual flair to study the smallest detail, from the wisp of lichen to the most concealed orchid and tree species. Their mind-boggling views reflected a telescopic and microscopic perspective, helping them to examine global and comparative patterns; their studies went down to the smallest cellular levels.

This forms a veritable prelude to the efforts being made by naturalists and botanists, during recent times, who have set their minds to shine a light on an astounding question, how many tree species are there on Earth?

Researchers from Botanic Gardens Conservation International in London, UK, have compiled a list to find at least 10,000 tree species, which are at a risk of extinction. The BGCI has been working for the last two years by consulting publications and allied resources across the world to rationalise 60,065 tree species involving a Global Tree Search. It is the first ever list of its kind, which has documented all the known tree species in the world and their countrywise distribution.

Astonishing as it may be, we were, hitherto, totally unaware of the number of tree species in the world. Global Tree Search has compiled the first global database of the world’s tree species, now published in the Journal of Sustainable Forestry, which highlights that more than half of all the species exist in a single country and many tree species may become extinct.

Of all the countries in the world, Brazil has the most tree species at 8,715, followed by Colombia, with 5,776 and Indonesia with 5,142. The Arctic and Antarctic have no trees at all, and the region with fewest tree species is the Nearctic region of North America with fewer than 400.

The database has more than 3,75,500 records that took more than two years to finalise. Paul Smith, secretary, BGCI, explains, “It is extraordinary that it has taken us till 2017 to publish the first global authoritative lists of tree species. Global Tree Search represents a huge scientific effort and lists tens of thousands of plant species. It also involves the work of botanists over the centuries.”The rationale behind this significant exercise of documenting the world’s tree diversity was to provide a tool for people trying to conserve rare or threatened varieties by 2020 — it will ensure that no tree species is lost forever.

Mark Kinver of the BBC singles out one threatened variety, Karomia gigas, a tree in Tanzania that has only six species remaining. Detecting a species’ location provides key information for conservation. On the other side of the coin, it also helps to decide the ones that must be assessed to verify their status.

Ecologists had recently toured the Amazon Basin, which has at least 11,676 tree species, estimating that about 4,000 in the area are yet to be discovered. Although botanists and naturalists have studied plants and trees in the Amazon Basin for centuries, no one had maintained a master list of tree species.

As many as 1,170 Amazon forestry surveys have been compiled over recent decades and it has now been estimated that the Basin holds 16,000 tree species and 390 billion individual trees. Tropical forest ecologist, Nigel Pitman, confirms that with the list they have of the Basin’s trees, they can at least compile a comprehensive list of number of species in the region and the scientific community can refine the list further.

The rainforests thriving in South America was, according to Darwin, “Like walking in a new world and the flowers would make a florist go wild, there were gaudy butterflies and I wasn’t sure what to look at or pick up first; it was a rare union of poetry with science.”