Researchers harvest flowers, fruit from critically endangered tree for conservation

SINGAPORE – The tree is 45m tall but that did not deter a team of researchers from the National Parks Board (NParks), who scaled the critically endangered Sindora velutina on Friday (June 10) to harvest its flowers and fruit for research and conservation.

The species has six known mature specimens, scattered across two nature reserves islandwide. The tree scaled by the team is the tallest and only one that produces viable offspring, said Ms Choo Le Min, senior researcher of NParks’ Singapore Botanic Gardens.

Species are critically endangered when there are fewer than 50 mature individuals known.

Ms Choo, who leads the research team, said: “Fresh flowers will show their colour, scent and shape, which give clues to what its pollinators are. If the pollinators can travel longer distances and cross-pollinate, genetic mixing can ensure the survivability of the species.”

The harvested flowers have a greenish-yellow exterior and the stamen, the pollen-producing reproductive organ, is pink. There is a light and powdery jasmine fragrance.

The fruits of the tree are long and disc-like, covered with thin and slender spines. Green when immature, the fruits will harden and turn brown when they ripen, said Ms Choo.

The species is more commonly found in peninsular Malaysia and Borneo, where the area of primary forests – dense, undisturbed areas that contain a large and diverse number of trees – is greater.

Dried flower specimens of Sindora velutina were last documented in 1954, but did not provide insight into the colour, scent and pollination biology of the tree, said Ms Choo. There were also no known photographs of the flower globally.

The tree, which is under the legume family, forms the canopy layer of the rainforest and shades the forest undergrowth. Oil extracted from the trunk used to serve lubricating and waterproofing purposes in the past.

Sindora velutina was presumed to be extinct until it was discovered by researchers from Nanyang Technological University in 2019. They alerted Ms Choo, who had been studying the Sindora genus as part of a cataloguing project called Flora of Singapore since 2018.

Researching on and conserving endangered tree species are especially crucial for a small country such as Singapore to ensure ecological connectivity, said Ms Choo.

“We have to know (the species’) distribution, rarity and population trend and which animals disperse their seeds.

“Every species is important because they are all interconnected – the loss of one species might have cascading effects on the whole ecosystem.”

The species is the rarest species under the Sindora genus – a category of plants that are closely related – that can be found in Singapore. The Republic is home to around 2,100 plant species.