Revegetation techniques

 

There are three techniques that are commonly used for revegetation: tubestock planting, direct seeding and natural or assisted regeneration.

 

 Direct seeding  Tubestock planting  Natural regeneration
 (+) Lower establishment costs  (+) More reliable  (+)Plants are well-adapted to the site
 (+) Natural look and more diversely structured  (+) Uniform  (+)Establishes healthiest plants
 (+) Establishes healthier plants (+) Revegetation is visible to passers by  (-)May have to wait for a long time for results
 (-) Long establishment times may lead to more maintenance such as weed control.  (-) Often results in unnatural looking rows  (-)Needs an adjacent or nearby seed source
 (-) Ants have been known to take seed  (-) Higher establishment costs  (+)Lowest establishment costs
 (-) Uses lots of seed  (+) Uses small quantities of seed  (-) Long establishment times may lead to more maintenance such as weed control.

 

Natural Regeneration

 

Natural regeneration is the term used to describe the growth of plants from seed naturally distributed to the site. Natural regeneration relies on existing seed sources, such as soil or canopy stored seed, or seed transported to the site by water, wind or animals in the area to be revegetated. This method of re-establishing vegetation is especially worthwhile for individuals and groups with limited resources. Natural regeneration is a good first choice, because native plants that grow from this method are likely to be well adapted to the site. If there is a good source of seed, natural regeneration can result in high species diversity, representing the original range of plant species.

 

Although the process of regeneration itself is 'passive', natural regeneration still usually requires facilitation and management. The areas to be revegetated are usually fenced to exclude stock and allowed to regenerate naturally. Some form of pre-treatment, such as a burn or herbicide treatment, may be applied to the site. If the regeneration fails or is poor, direct seeding or planting seedlings can be considered. As with other methods, implementation of a long-term weed management strategy is important.

 

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Direct Seeding

 

Direct seeding involves sowing seed directly into prepared ground. Direct seeding generally is more efficient in terms of time, cost and labour, compared to tubestock planting. It also allows for a more diverse seed mix, leading to greater plant diversity. The main limitation with direct seeding is usually the availability of seed. Establishment of plants from direct seeding can be patchy and can take several years, especially for hard-seeded species, but the plants that do establish are often robust and have developed a good root system. There are two main methods of direct seeding:

  1. Hand Sowing: this method is useful for small areas or in inaccessible country. Handfuls of seed mixed with a bulking agent are thrown onto the prepared seed bed. Another method of hand-seeding uses cut stems of a plant with ripe fruit present, laid across a prepared site.
  2. Mechanical direct seeding: this method involves the use of specialised direct seeding equipment, which is calibrated for different seed sizes and planting depths. Large areas can be seeded quickly using this method - up to 50 hectares in one day using one direct seeder. 

As with other revegetation methods, ground preparation and weed control is critical.  Because germinating seeds must compete with weed seeds that may be in the soil, a weed control program ideally should begin two years before direct seeding. The top layer of soil can also be scalped to remove weed seeds. Control of seed and shoot predators such as ants and red-legged earth mites is also important.

 

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A combination of direct seeding and tubestock planting has been used at this site in Victoria, to increase the diversity of species.

 

Tubestock Planting

 

'Tubestock' is the term for seedlings that have been raised in small nursery tubes, for transport to the planting site. Propagation of seedlings can be by seed, by cuttings, or through division. Seedlings can be planted by hand or with a mechanical seedling planter at the prepared site. As with direct seeding, site preparation is essential and will involve weed control and fencing.

 

Even though tubestock planting is more expensive and requires more labour than direct seeding and natural regeneration, it is a widely used method of revegetation. Results are reliable and immediate, and plant placement is controllable. Because of the labour-intensive nature of tubestock planting (both in propagation and planting), fewer species tend to be planted than with direct seeding.

 

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Next   Site preparation - weed control

 

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