Screen plantings consist of rows of closely packed shrubs or trees, either trimmed as a hedge or untrimmed as tightly grouped plantings. If sited correctly, these windbreaks can filter out a large proportion of the burning debris that are carried by the wind during a bushfire. All low flammability vegetation has some screen-forming abilities if it is managed and maintained appropriately. Ornamental and orchard trees in particular can be effective barriers if sited and managed correctly.
- Choose species with moderately dense foliage (not too dense and not too sparse). Generally, fire will burn quickly through foliage that is overly sparse. Dense foliage, on the other hand, can block embers and block or deflect radiant heat and flame; however, windbreaks require some permeability to prevent negative pressure on the lee-side of the barrier. This negative pressure can cause dangerous levels of turbulence during a bushfire.
- Keep the area around the windbreak clear of continuous vegetation.
- Keep plantings to a manageable size – large, overgrown vegetation is more vulnerable to bushfire.
- Position the screen plantings between the house (or other feature that you wish to protect) and the direction of the bushfire hazard. Leave
a separation distance of at least two times the mature height of the tree (or 10 meters, whichever is greater) between the windbreak and the protected feature.
- Avoid highly flammable species.
- Avoid species that produce a lot of dead plant material.
- Avoid species which retain dead foliage after pruning.
- Avoid species with abundance of an oils, waxes and resins in the leaves and stems.
A row of evergreen trees can create an effective barrier (source: SteveLovegrove/Shutterstock)