Planning your revegetation
Favourable seasonal conditions have encouraged renewed interest in replacing or revegetating new areas in our landscape. It is important to carefully plan your revegetation project, taking into consideration what you aim to achieve with your planting, where you will be planting, what species you will plant and how you will plant them.
Once you have completed a detailed plan for the revegetation project, you will know what materials, plants, equipment and labour will be required to complete the planting so that you can accurately cost your project.
Aim of the planting
For each new planting you need to consider what you aim to achieve. Is it purely to make your property look good or do you want a functioning windbreak or wildlife habitat corridor? Do you want to screen out a particular view, reduce noise or filter potential chemical spray drift?
The answers to these questions will impact the planting design in terms of site location and dimensions, plant density, plant layout, species selection and even planting technique. Some reasons for planting include:
A good windbreak can slow wind speed up to 80%—very handy in reducing crop and pasture moisture loss and stock stress. When positioned correctly, windbreaks function up to 20 times their height across the paddock, with best results within 10 times the height. For example, a 15m high windbreak will be effective for up to 300m but most effective within 150m. Although the trees take up land and can rob adjacent crops and pastures for a distance equal to about twice their own height, they shelter a much larger area and the benefits far outweigh these losses.
Windbreak design principles
- Best results are achieved when the windbreak is perpendicular (at right angles) to the problem wind. This offers the greatest resistance and distance benefit. As the angle decreases, so does effectiveness. A windbreak that runs parallel to the wind offers no protection. If it’s practical and the risk of localised frost is low, consider planting your windbreak in a curve, such as along an elevation contour, so there is always a portion of the break perpendicular to the wind.
- A good windbreak should be around 40% porous, sparse enough to encourage the wind to flow through but dense enough to offer resistance and slow down the air speed.
- Give your plants room to grow—a minimum of 25m for a four row break. Tall, bushy plants cannot be achieved if plants are packed like soldiers on parade.
- Plant the outside rows with shrub species. This will provide low foliage cover and reduce the moisture and nutrient robbing effect of large trees on adjacent pastures and crops.
- Try to avoid gaps and short windbreaks as wind can deflect around the ends of the windbreak and increase wind turbulence.
- Plant losses should be replaced in the next planting season. A windbreak with holes is ineffective and may even cause wind tunnelling (a localised increase in wind speed).
- Because of the need for precise plant position, plant your windbreak using seedlings rather than direct seeding methods.
Trees and shrubs may be used as visual barriers to block a view, noise screens that reflect back offending noise or as buffers to filter spray drift from adjacent activities such as intensive cropping or horticulture.
Screening design principles
- Visual barriers: Structure visual barriers like a windbreak with the outside rows planted with shrubs to produce a low hedge-like cover.
- Noise screens: The rows should be positioned to reflect the sound with space between to create a large baffle-like structure. The suggested distance between rows for this type of planting is approximately 12m. You should use a mix of trees and shrubs along your row to ensure good foliage cover from ground to tree height. The wider the planting, the better—ideally aim for a minimum width of 30m or three widely spaced rows.
- Spray drift buffers are designed to filter spray drift from adjacent activities such as intensive cropping or horticulture. Like windbreaks, spray buffers need to encourage airflow through the planting, not over it. Spray drift buffers are generally sparser (approximately 30 to 50% porous) and consist of a large variety of foliage types (fine to coarse foliage).This maximises the filtration of airborne particles. The wider the buffer, the better (a minimum suggested width is 40m). Buffers also need to be as close as practical to the spray source—the further away, the less effective.
- Because of the need for precise plant position, plant your screening projects using seedlings rather than direct seeding.
Wildlife habitat corridors
Native vegetation can be planted to provide habitat for wildlife and assist wildlife movements across the landscape by connecting patches of remnant bushland.
Wildlife habitat and corridor design principles
- To be effective, wildlife corridors should connect at least two patches of remnant vegetation. Try to avoid gaps that include barriers such as roads, which can inhibit the movements of small mammals.
- It’s a good idea to plant alongside remnant vegetation such as travelling stock reserves, roadsides or creeks.
- This protects or buffers the remnant vegetation and increases the habitat value of both the revegetation and remnant site. Wildlife in the adjacent remnant vegetation will be able to immediately use your revegetation site and plants from the remnant area may naturally regenerate in the revegetation site, improving the complexity.
- Habitat corridors are most effective when they contain a variety of open and dense areas (habitat mosaic) and a high diversity of native plant species and types (mix of large and small trees, shrubs and native groundcover).
Habitat mosaics with a shrubby understorey provide habitat for a greater variety of wildlife.
- Size is important. In general, the wider, the better. This creates a ‘core’ area that is free from edge effects and will provide habitat, rather than just a corridor for wildlife movement. Wide corridors, greater than 30m, may be used by less common wildlife (declining species) and narrow corridors are often dominated by common, aggressive birds such as ravens, magpies and noisy miners (increaser species).
- Incorporate other habitat features into your site such as mature paddock trees, rocky outcrops and fallen timber. These features will greatly increase habitat diversity.
- Direct seeding is the ideal method for establishing habitat areas as the unpredictable results add complexity to the design. It can also reduce establishment costs. If you are using seedlings, avoid planting at set intervals along your rows. It is not uncommon in native woodland to have distances of 30m between some trees.
- Randomise the distance between seedlings and the rows. Row spacings should be wide to allow native groundcover species to regenerate. Consider putting curves in your rows — this will greatly enhance the mosaic effect.
If you aim to create wildlife habitat with your planting, consider using plain wire. Many birds, bats and gliders become entangled in barbed wire and die.
Planting alongside watercourses in the ‘riparian zone’ can provide important habitat for wildlife and help to improve water quality by filtering sediment and nutrients from the surrounding landscape. This is most effective if close to 100% groundcover is maintained.
Riparian revegetation design principles
- In general, the wider the buffer zone, the better. The recommended minimum width for most small creeks and drainage lines is an average of 20m either side of the water course with give-and-take, to account for bends in the course of the creek.
- No trees or shrubs should be planted in the channel or main water flow area as these plants could obstruct the flow of water and cause erosion.
- Site preparation should be kept to a minimum and timed appropriately to reduce the risk of erosion. The use of chemicals to control weeds should also be minimised and must comply with relevant regulations.
- Any woody weeds such as willows should be treated prior to any new vegetation being planted. Removal of any vegetation on State Protected Land (which includes riparian land) may require approval so please check with your Local Land Services Officer prior to undertaking these activities.
- Plant reproductive material (such as seeds and root suckers) may be easily transported downstream so it is important to only use locally occurring plants, native to your area.
- If the site needs to be fenced to protect the new vegetation from stock, you may need to consider alternative watering points for stock.
- Due to the need to retain groundcover and minimise site disturbance, the use of spot planting techniques (using seedlings or seed) is recommended.
Click here to view the publication titled 'Planting your patch: A guide to revegetation on your property '. This guide is designed to provide you with the information you need to re-establish trees, shrubs and groundcovers back into your landscape to ensure you gain the maximum benefit from your investment and it achieves its purpose.
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