Unit
Saltland UniExplore SolutionsGenies AdviceGenies MapsGenies LibrarySaltdeck Cards
Unit 1 - What's in it for me?
Unit 2 - Saltland Basics
Unit 3 - Can I trust the technology?
Unit 4 - Plant and animal performance
Unit 5 - Sheep, cattle and conservation
Unit 6 - Do the $$$'s stack up?
Unit 7 - The saltland toolbox
Site Assessment
Solution 1: Exclude grazing
Solution 2: Volunteer pasture
Solution 3: Saltbush
Solution 4: Saltbush & Understorey
Solution 5: Tall Wheatgrass
Solution 6: Puccinellia
Solution 7: Vegetative grasses
Solution 8: Temperate perennials
Solution 9: Sub-tropicals
Solution 10: Legumes
Solution 11: Revegetation
Solution 12: Messina
Solution Explorer
Genie's Advice
Genie’s Maps
FAQ
NSW
SA
TAS
VIC
WA
Farmer Stories
Case Studies
Film Clips
Research Reports
International Salinity Forum
SALTdeck Cards
Published Products
SALT Magazines
Photo Gallery
Saltland Pastures Association
Farmer Stories
Case Studies
Film Clips
International Salinity Forum
Research Reports
NDSP Archive
Saltdeck
Published Products
Photo Gallery
Saltland Pastures Association
Catchment Management Plans
Farmer Stories
Case Studies
Published Products
Photo Gallery
Research Reports
Genie Film Clips and YouTube
Catchment Management Plans
Saltdeck Cards
Saltland Pastures Association
NDSP Archive
Salt Magazines



SOLUTION 11

Revegetating with non-grazing options

 

11.1 Revegetating with non-grazing species in a nutshell

Next

A quick summary

In this website which details solutions for saltland, there are two solutions that do not involve grazing:

  1. Fence and exclude from grazing is recommended for saline sites that that are too saline, waterlogged and/or inundated for other solutions to succeed. This solution is primarily based on fencing to exclude grazing and allowing samphire and other highly salinity and waterlogging species to colonise.
     
  2. Revegetating with non-grazing species (this Solution) is recommended for a much wider suite of saline sites where grazing may be a suitable land use, but other considerations lead to a rehabilitation plan that includes trees or other non-grazing species as a major component of the revegetation mix. Occasional grazing may be part of this solution, but only at times and at grazing pressures that do not threaten the other benefits being sought – such as erosion control, timber production, biodiversity or visual amenity.

Within this non-grazing option, there are 3 basic strategies that all involve fencing a saline site off from grazing and:

  1. allowing natural revegetation for conservation and/or visual amenity. This strategy relies on species of interest or value establishing unaided - a big challenge for saline sites.
     
  2. revegetating with trees, shrubs and/or under-storey but with the selection of revegetation species focussed on conservation and visual amenity, with no aspirations for a commercial product. This strategy is probably the most likely of the three to be successful, because it involves a range of species, and commercial growth rates are not expected.
     
  3. revegetating with trees, with the species selected for commercial wood products (saw logs, pulp, firewood) rather than conservation or visual amenity. This strategy is the most challenging because a more limited range of species will be planted, and both the biology and the marketing aspects have to align if a profit is expected. For more information, see Links between small-scale growers and industry.

As the first strategy requires no intervention (other than fencing off the site), this Saltland Solution focuses on strategies 2 and 3 above. Although some opportunistic grazing may be involved, we will focus primarily on the forestry component as the grazing options are covered in the other Saltland Solutions.

Most trees are not halophytes (salt loving plants), so saltland inevitably provides a hostile environment, especially if waterlogging adds a further stress to many trees. Part of the appeal of agro-forestry or woodlots with salt- tolerant trees over shallow watertables is the opportunity for these to access abundant water. However there is a question mark over the sustainability of this enterprise if it leads to accumulation of salt in the root zone.

Notwithstanding this, considerable research has been directed towards identifying salt- and waterlogging- tolerant tree species and developing particularly tolerant hybrids and cultivars.

An upside of growing trees on land of low to moderate salinity is that it is a low maintenance option which can be suitable for areas that might be too small to manage for grazing or that do not have a water supply for livestock. It can also offer side benefits of reducing saline runoff from waterlogged sites and provide strategic shelter for livestock, such as sheep off shears.

The current interest in planting trees for greenhouse gas abatement may add significantly to the motivation for establishing trees. This could be particularly attractive for saltland which apart from grazing, has few other prospects for productive use. The September 2007 edition of the SPA newsletter contains some articles about carbon sequestration and bio-diesel.

Top

History

The first researchers to investigate the planting of trees on saltland in Australia were Rick Pepper and Gillian Craig who tested the relative performance of 12 different eucalypt genotypes on a saline site near Brookton in Western Australia in 1976. Subsequent researchers then began to test the tolerance of tree genotypes to salinity and to salinity with waterlogging under glasshouse conditions.

The group that has been most active in the development of trees for saltland is arguably CSIRO Forestry and Forest Products (Drs Marcar, Morris and Thomson). Useful summaries of the changing state of play in the field can be obtained from Nico Marcar’s papers to PUR$L Conferences (commencing in 1990) and the books written by him and his colleagues.

Most of the impetus behind the use of trees on farms for salinity management has focussed on planting trees to reduce recharge. Throughout the 1990s it was widely thought that strategic tree planting on farms would reduce recharge sufficiently to overcome dryland salinity, and many farmers planted modest areas, usually corridors or fence-line plantings. This activity was a massive undertaking by Landcare groups and individual farmers, often supported by public funding. During this time, saltland pastures were hardly on the radar as individuals and groups focussed on ‘winning the war against salinity’, making any other option an admission of defeat. However, the catchment modelling carried out by the National Land and Water Resources Audit showed that in most catchments, the areas of tree planting needed to make a significant difference was much greater than was possible through voluntary schemes.

This turned the attention more from preventing recharge, to managing discharge as a primary catchment strategy. Instead of planting trees to prevent general recharge, the focus has shifted to planting them around the edges of saline areas and even within them.

There are significant hurdles for saline forestry. The most important commercial eucalypts and Pinus radiata do not grow at all well on saltland, and since dryland salinity is most commonly found in the 400-650mm rainfall zone, which is typically more than 100km from coastal ports, there is little commercial prospect for short-rotation pulpwood. Instead, trees have mainly been grown for firewood, honey or for on-farm use such as fence posts.

Despite these challenges, there has been considerable interest in enhancing the value of salt-tolerant trees by developing pulpwood and/or sawlog species. This has been particularly the case for irrigation areas where rising saline groundwater threatens high value crops, and where salt-tolerant trees can both reduce recharge and tap directly into the watertable.

Water pumped from saline aquifers or from wastewater treatment plants is also applied to salt-tolerant trees which act as a sump but also provide the opportunity for a commercial return from the product. This latter application has been a significant driver for the development of more salt-tolerant commercial varieties.

Top