What do you think of the city's tree protection measures?
The fatal collapse of an old tree in Stanley highlights a long-standing problem that appears to have been overlooked by the government ('Pledge to check treasured trees after one collapses, killing teen', August 28).
Many older trees in Hong Kong are parasitised by strangler figs whose seeds, dispersed in bird droppings, germinate in crevices high up in the host trees. The seedlings grow aerial roots that descend from the host tree.
In a natural environment, when these roots meet the ground, they penetrate it and thicken to form strong buttress-like formations and trunks that surround the host, gradually but literally strangling it. The host dies and decays, leaving the fig to stand alone.
In Hong Kong, however, most urban trees are closely surrounded by paving stones or concrete, and when the strangler figs' roots reach the ground, they are unable to penetrate very far, if at all. Consequently they do not grow strong enough to support the weight either of the dying host or the fig itself. This is a situation that requires close monitoring.
Ideally, old and valuable trees should be inspected regularly for signs of parasitisation by the strangler figs and all parasitic growth eradicated.
Tony Giles, Kennedy Town