Choosing trees for the tropics



Many trees were uprooted, destroyed or stripped bare across the North of Queensland recently after Tropical Cyclone Yasi hit the region, but residents can help avoid this in future with the help of a new guide for choosing plants for cyclone-prone areas.

Adjunct Associate Professor Betsy Jackes, from JCU’s School of Marine and Tropical Biology, has written “Choosing Plants for Areas Prone to Cyclones” after studying the topic for almost 40 years.

Associate Professor Jackes said some trees “just didn’t like” strong winds.

“No tree will always stand up to cyclonic strength winds and there are many factors which influence their ability, however some are more wind-resistant than others,” she said.

“How well a tree performs depends on many factors such as how wet the soil is at the time, the intensity and duration of strong wind gusts and particularly the type of root system.”

The guide lists the advantages and disadvantages of a range of trees and shrubs, characteristics of suitable trees and shrubs, factors affecting stability, the main causes of ‘failure’, guidelines if planting for cyclones and the specific responses of many species commonly grown in North Queensland.

Professor Jackes said the production of the guide was not inspired by Cyclone Yasi in particular.

“I have been collecting this information ever since Cyclone Althea and together with input from others, have been compiling information on most cyclones,” she said.

“This information compiled from a number of reports has been combined with my own observations, based on behaviour of trees in Althea, Winifred, Larry and now Yasi.

“I decided to write the guide after several people made suggestions that since I had a number of lists and general information, that this should go on the website to be readily available.”

She said her observations included any area where cyclones had hit the Townsville region since Cyclone Althea in 1971.

Much of the material has also been included in Associate Professor Jackes’ lectures for the past 15 years.

Associate Professor Jackes said the guide was designed as a simple one, to help people choose suitable trees and shrubs for their garden, although she hoped it would also be useful for developers and councils.

Despite the cyclone-related destruction in gardens across the region, Professor Jackes urged people not to panic and convert to a tree-less landscape.

“Don’t be deterred from planting such trees and shrubs because you might have 20 to 30 years of pleasure from them; just make sure that when they do fall they won’t cause any serious damage.

“Just check on their potential height at maturity and if necessary, be prepared to prune. However, regrowth branches are often not as strong as original branches.”

Photographs will gradually be added to the site and others can be found on the Flora and Fauna section of the JCU web site.

The guide, which is relevant to all north Queensland communities as well as Darwin, is available on JCU’s website.