SINGAPORE - An iconic Angsana tree outside the School of the Arts in Dhoby Ghaut will be cut down on Sunday (Jan 21) as extensive decay has changed it from "a thing of beauty" to an object of danger.

Estimated to be about 40 years old, the tree - known as the Tree of Knowledge to some students or, more commonly, the Sota Tree - protrudes out of the school's stone steps and towers over the walkway.

When Sota was constructed eight years ago, consultants took care to include the tree into the design of the school facade.

In a statement on Friday morning (Jan 19), a school spokesman said the tree has "battled the harsh weather and thunderstorms over the year". The school had cables installed in 2014 to support and hold the tree up.

In 2013, an arborist reported that the tree showed signs of decay at its base. Last Thursday, it was reported that the tree's condition had deteriorated, with significant decay and a cavity at its base.

"For the safety of students, staff and members of public, the tree will be removed by this week," said a school spokesman.

The Sota community commemorated the tree with a farewell event on Friday evening.

More than 200 students stood at the top of Sota's grand steps to bid their final goodbyes to the 33.6m-tall tree.

At the ceremony, Sota principal Lim Geok Cheng called the tree an important landmark for Sota. "It was a thing of beauty... and graciousness... that provided shade and tranquillity," she said.

Year 4 student Jomel Goh, 16, said: "We didn't think of it much before, but it was something we would always look out for when going to school."

Fellow student Faith Lim, 16, said that she was sad to see the tree go.

"We used to sketch people under it for visual arts lessons," she said.

The ceremony also saw students singing pop and country tunes and a dramatic viola performance.

Year 6 theatre student Naja Surattee, 18, conducted a dramatic reading of an excerpt of The Giving Tree, a book by Shel Silverstein. Students reflected silently with sad expressions as the reading went on. Some lit tiny candles. A few students were also seen with tears rolling down their cheeks, clapping as the reading ended.

Mr Zainudin Samsudin, 43, a visual arts lecturer, helped craft stamps of the tree's leaves for those at the vigil to use, creating a colourful 1.8m by 5m heart-shaped mural titled For The Love Of Knowledge.

"The mural represents the colour the tree brought to our school, and the memories we made with it," he said. "I felt like this was the best way to capture the essence of the Angsana."

"Even alumni came back for the farewell, showing their attachment to the tree," he added.

After the tree is removed on Sunday, the school will create works of art from parts of its trunk and plant a new sapling at a later date.

"We had hoped to keep the tree standing on our steps for as long as possible, but there is only so much we can do," said Ms Lim. " While it saddens us to bid farewell to the Tree of Knowledge, we hope that its legacy lives on and a new sapling will be planted."