There are about 73,000 tree species on Earth, including around 9,200 yet to be discovered, scientists have estimated.

The worldwide estimate is approximately 14% higher than the current number of known tree species.

It is hoped the new findings, made using modern developments of techniques first devised by mathematician Alan Turing during the Second World War to crack Nazi code, will help prioritise forest conservation efforts.

Forests provide many services to humanity, including supplying timber, fuelwood, fibre and other products.

Among other things, they clean the air, filter the water, and help control erosion and flooding, as well as help to preserve biodiversity, store climate-warming carbon, while offering recreational opportunities such as hiking, camping, fishing and hunting.

The study involving more than 100 scientists suggests most of the undiscovered species are likely to be rare, with very low populations and limited spatial distribution, the study shows.

Because of this, the undiscovered species are especially vulnerable to disruptions caused by humans such as deforestation and climate change.

University of Michigan forest ecologist Peter Reich, one of two senior authors of the paper, said: “These results highlight the vulnerability of global forest biodiversity to anthropogenic changes, particularly land use and climate, because the survival of rare taxa is disproportionately threatened by these pressures.”

He added: “By establishing a quantitative benchmark, this study could contribute to tree and forest conservation efforts and the future discovery of new trees and associated species in certain parts of the world.”

Researchers combined data from two global datasets, one from the Global Forest Biodiversity Initiative and the other from TreeChange.

The databases yielded a total of 64,100 documented tree species worldwide, similar to a previous study that found about 60,000 tree species on the planet.

Jingjing Liang of Purdue University, coordinator of the Global Forest Biodiversity Initiative, said: “Counting the number of tree species worldwide is like a puzzle with pieces spread all over the world.”

After combining the datasets, the researchers estimated the total number of unique tree species, including those yet to be discovered and described by scientists.

The study estimates the total number of tree species on Earth is 73,274, indicating about 9,200 tree species yet to be discovered.

According to the researchers, their new study uses a more extensive dataset and more advanced statistical methods than previous attempts to estimate the planet’s tree diversity.

It is thought that around 40% of the undiscovered tree species are likely to be in South America, more than on any other continent, which is mentioned repeatedly in the study as being of special significance for global tree diversity.

South America is also the continent with the highest estimated number of rare tree species, about 8,200, and the highest estimated percentage of species found only on that continent, the research suggests.

The tropical and subtropical moist forests of the Amazon basin, as well as Andean forests at elevations between 1,000 metres and 3,500 metres are likely to be hotspots of undiscovered South American tree species.

Across the world around two-thirds of all already known tree species occur in tropical and subtropical moist forests, which are both species-rich and poorly studied by scientists.

These forests likely hold high numbers of undiscovered tree species, the researchers say.

Study lead author Roberto Cazzolla Gatti of the University of Bologna in Italy, said: “Extensive knowledge of tree richness and diversity is key to preserving the stability and functioning of ecosystems.”

The findings are published in the Proceedings Of The National Academy Of Sciences Journal.