Injured trees need their wounds dressed just like people. And, like humans, that includes bandages and the arboreal equivalent of band-aids.
Now, however, researchers have come up with a new means of treatment: ordinary exterior house paint.
After a nine-month study they say the paint can seal the wounds and prevent the trees from attack by fungus and termites that can kill them or cause them to fall, endangering pedestrians.
The study, led by Dr Chiu Siu-wai, a fungus expert at Chinese University's school of life sciences, has found that tree wounds covered by the water-based, environment-friendly paint fared better than those treated by traditional methods.
'Some tree wounds are wrapped only with loosely-knitted nets. With such big holes, you can imagine how easy it is for fungus to enter and thrive inside the tree,' Chiu said.
Paint has also been used in the past but it is a special product for the purpose and much more expensive.
'We used to seal the tree wounds with a specific paint which can only be found in two shops all over the city,' Wong Bing-hung, landscaping manager of the university's estates management office, said. 'It's at least ten times more expensive than ordinary house paint.'
Government regulations do not require tree wounds to be sealed in this way. A maintenance brochure issued by the Tree Management Office last year clearly stated, 'No need for wound dressing.' The office had not responded to requests for comment last night.
Drawbacks of the paint dressings include the possibility that they may inhibit a tree from using its own defence system and might not last long, even if initially effective.
'As a human, you need to apply medication to the wound daily until it's healed,' University of Hong Kong tree specialist Professor Jim Chi-yung said. 'Same for the trees. The paint cannot extend as the tree grows, leaving cracks for attacks.'
Recent years have seen an increase in the cases of injuries or deaths caused by falling trees or branches.
According to a report released by the Tree Office last year, about 2,000 trees in Hong Kong have been put on the list for careful inspection.