The Southern Highlands has experienced its fair share of windy weather this winter. A well designed windbreak can be a welcome relief from the wind. Native plants are a crucial choice in developing windbreaks – with correct species selection you can achieve a long-lived, sustainable and beautiful windbreak that not only provides protection from the wind, but also benefits the local ecology.
Unfortunately many windbreaks in the Southern Highlands are poorly designed and utilise unsuitable species. A common sight in the Highlands is a single row of Leylandii planted as a windbreak – they are ineffective windbreaks and contribute nothing to our local ecology and are also a fire risk. Windbreaks created with Leylandii or similar species obstruct the wind and which then creates turbulence. Very effective wind protection is achieved but for only a relatively short distance on the leeward side of the windbreak. Once out of this minimal protected zone, wind speeds and turbulence increase with intensified risk of damage to crops, gardens or structures. Leylandii are extremely dense and may be effective as a hedge if clipped but would be determined as completely unsatisfactory as a windbreak when the science is considered.
A well-designed windbreak should divert and muffle the wind rather than obstruct it. The efficiency and effectiveness of windbreaks depends upon the height of the windbreak, its width, density and porosity plus its orientation. Porosity would be considered the most influential factor determining the effectiveness of a windbreak. Porosity relates to the amount of air allowed to pass through or be muffled by the windbreak. The denser the vegetation a tree has the less effective it is as a windbreak.
If you are seeking advice as to design and species selection for a windbreak, ensure the advice you act on is not driven by myth, ignorance or prejudice.