Effort underway to breathe new life into Bangkok’s ageing trees

FRIDAY, JULY 07, 2023

The Bangkok Metropolitan Administration (BMA) is working with the Big Trees Foundation and private companies to breathe new life into decaying rain trees inside Benchakitti Park, as city officials strive to add more green space to the capital and protect the small pieces that survived decades of rapid expansion.

Most of the city’s green areas were transformed into construction sites as economic growth transformed Bangkok into a metropolis. But as the city expanded, buildings supplanted trees and most of those left are ageing and in decay, officials say.

The BMA’s Environment Office, Big Trees Foundation, Thai Beverage Plc, and the organisers of Sustainability Expo 2023 are working together to save the last large rain trees in Benchakitti Park, which is located next to Queen Sirikit National Convention Centre.

A recent survey by Big Trees and the Thai Arboriculture Association found that 15 rain trees in the park have decaying roots, mould, and are infested with worms. The soil around their roots is also too tightly compressed.

The rehabilitation effort started with trees in “critical condition”. They are all located in the park’s skywalk zone. They were pruned about one month ago and have since started sprouting new leaves.

Other measures taken include adjusting the height of soil around the trees, eradicating insects and germs, loosening the soil around the roots, removing extra soil from the root area, watering with a hormone solution to revive the roots, and making a ventilation pipe for the roots.

Air spading uses high-pressure jet spraying to reduce compacted soil beneath the rain trees to allow better ventilation. This method of soil loosening can prevent damage to the roots. 

Mulch is then applied to the soil around the trunks to loosen the soil and reduce evaporation. This protective covering of rotting vegetable matter also doubles as fertiliser. In the second phase, four more rain trees will be saved.

The project’s progress can be followed on the Facebook page of the Sustainability Expo or its website www.sustainabilityexpo.com. The Sustainability Expo 2023 will be held between September 29 and October 8 this year at the Queen Sirikit National Convention Centre.