A strong odor has recently been -plaguing the residents of Pingtung City during the night. Many of them thought it was the fault of the smokestacks in nearby industrial plants, but then discovered that the real culprit was a tree.
The smell that was making the residents feel nauseous and triggering headaches was coming from a type of evergreen tree called Alstonia scholaris — better known as the “Blackboard tree” or “Indian devil tree.” The tree is native to India and Southeast Asia, where its timber was commonly used to make blackboards for schools.
The neighborhoods of Yongsin Park (永新公園) have blackboard trees all around them and the trees’ intensely fragrant flowers bloom each November throughout the month.
During the night, the air becomes thick with the flowers’ pungent odor, preventing some people from sleeping. In the springtime, the trees produce wind-blown cotton seedlings that can cause health problems for asthmatics.
Residents’ patience with the trees has run out and they are demanding that the odor emitters be cut down. They say that if the city government cannot find a solution, they will demand compensation from the central government for the psychological and physical damage they have suffered due to the trees.
“I cannot stand it anymore. It stinks too much,” a resident said.
Officials from the Pingtung City Public Works Bureau said they receive a large amount of complaints during the tree’s flowering and seeding seasons. Aside from affecting some people’s health, the trees have adversely affected business at some local stores.
Some of the blackboard trees growing in schools and private households have already been felled and replaced with other varieties. However, officials say that blackboard trees in public spaces — such as those dotting the parks, river levees and sidewalks of the city — cannot be dealt with so easily as they propagate large numbers of seeds that have a rapid growth rate and thus their outward spread is not easily controlled.
An unnamed official at the Pingtung County Forestry Bureau said the offending trees did provide some advantages, such as being able to form leafy canopies that create shade in just a couple of years. However, he did add that another main drawback of the blackboard tree was its spongy wood, which makes it prone to toppling over in strong winds.
If people are not willing to chop the trees down, the official advised that they trim the leaves and branches just before the flowering season because this can prevent the release of the irritable odor and seedlings.
Officials from the Public Works Bureau said that they do not have the funds to carry out year-round trimming on all of the blackboard trees in the city.
However, they are planning to encourage schools and other public facilities to plant other types of trees when blackboard trees topple over in storms or die naturally to gradually phase them out.
Chen Chia-yin (陳嘉音), principal of the city’s Chihcheng Junior High School, said there used to be more than 30 blackboard trees at the school.
“Some of the trees are close to classrooms. The odor and release of the fibrous seedlings can severely affect students in class,” Chen said.
He said that the school asked the county government to cut some of the trees down and replace them with othes, and the school has only 10 trees left.