A three-year battle to save one of Macao’s loveliest banyan trees from brown root rot has finally come to an end with the tree – ficus microcarpa – earmarked for felling within the next few days.
The Municipal Affairs Bureau (IAM) said that the tree in Mong-Ha Hill Municipal Park needs to be removed as it has been infected with phellinus noxius (or brown root rot) which increases the danger of the tree falling.
IAM staff had tried to treat the tree but the brown root rot could not be eradicated. The bureau has decided to remove the tree for public safety within the next few days and urged residents to avoid getting close to the area.
The IAM pointed out that phellinus noxius is a type of root fungi that will kill the roots and cause the infected trees to wither, and the fungi will also rot through the decayed wood tissue which makes the roots and trunks become fragile.
IAM staff discovered during a regular check in 2019 that the leaves of the ficus microcarpa were sparse. After a detailed inspection of its roots, the bureau confirmed that the tree has been infected with phellinus noxius, and part of the roots were already rotting, so staff took measures that included pruning to reduce the weight of the crown of the tree, tying the tree for stability, as well as infusing fluid into the tree for treatment. Staff also removed other diseased plants and roots near the tree.
During a review in 2020, staff discovered that the infected roots were dead and had already expanded to the ground area, where mycelium (the vegetative part of a fungus) had grown on some of the roots, so they treated the tree again and reinforced the monitoring activity. The bureau then set up a divider and kept spraying chemicals over the tree in 2021. However, although the tree looks intact, the infected roots are seriously rotted and the trunk is fragile and has lost its anchorage. After the assessment and in order to prevent the danger of the tree falling, the bureau has decided to remove the tree as soon as possible.
The IAM noted that as Macao is getting into the rainy and typhoon seasons, its staff will pay close attention to the daily pruning of trees with a dense canopy and check on trees that are in a bad condition and follow up on the issue when a potential safety hazard is discovered. The bureau urged the public to avoid going into a forested area or standing under the trees during windy and rainy weather or days afterwards, in order to prevent the risk of being hit by falling branches, The Macau Post Daily reported.