Storm damage on urban trees in Guangzhou, China

Abstract

Guangzhou is the largest city in subtropical South China with a significant tree cover and a long history of urban greening. Its precious tree stock is subject to a wide range of natural and artificial stresses, one of which is strong wind associated with thunderstorms and typhoons. On 9 April 1995, a windstorm of extreme intensity struck the city and brought havoc to the tree population. A detailed survey was conducted immediately after the storm to collect quantitative information on 1782 trees encompassing 89.5% of the total spoiled-tree population. The study was aimed at understanding the nature and extent of wind damage on urban trees with reference to species, dimension (age), site characteristics, land use and urban history. A brief review of tree composition, habitat conditions and tree management responsibilities in the city, and a computer inventory on urban trees established earlier, provided a benchmark for data interpretation. Damage was generally independent of size despite the conspicuous loss of some large and champion-calibre specimens. Tree size, however, was related to the mode of damage. Ten species constituted the bulk of the destruction. Roadsides and green spaces had somewhat different assemblages of afflicted species. Recent widespread construction activities had weakened many street trees and predisposed them to injuries. Old districts with more old trees were more seriously affected. North districts which registered much stronger winds took up over 80% of the toll. Different phases of management responses to the natural disaster and the related administrative organization were assessed. Management implications of the findings were discussed with a view of rationalizing responses and reducing future wind damage.