Rising groundwater levels and salinisation of land and water is a growing problem, and there is an urgent need for identifying the most appropriate and cost-effective land uses to manage rising water tables and salt mobilisation across the country. Whilst it is possible to do this at a planning scale for specific, intensively studied catchments, it is not feasible to carry out similar resource-intensive investigations for all other, unstudied catchments, and we currently lack the tools for generalising our knowledge of the processes operating in these catchments to other unstudied catchments at scales that are operationally meaningful. Furthermore, although there is a good understanding amongst specialists of the importance of hydrogeological processes in controlling salinisation, this understanding is not widely appreciated amongst stakeholder groups and funding agencies.

Research

Initially, a discussion paper was prepared on the use and feasibility of developing a national catchment classification system. This was followed up by a two day workshop in Canberra (21^st and 22^nd of April, 1997) to investigate the feasibility of pursuing a classification-based approach to catchment hydrogeology. A subsequent workshop was held in Canberra (7^th of October, 1997) as a direct recommendation of the initial workshop, to identify a set of conceptual models of salinisation processes across the continent. Subsequent discussions elaborated on the models identified in that workshop, and a report was prepared on the identified models and their application across the continent.

Outcomes

Fifteen generic hydrogeological models were identified to explain the occurrence of dryland salinisation across the continent. These models described the broad characteristics of salinisation across Australia, although the relevance of the models to specific sites would need to be interpreted in the context of additional, local data. The models also considered the different scales of processes involved in salinisation, whether these be local, intermediate or regional groundwater flow systems. The specific settings of the models were described for each state where they were known to occur.

Two types of datasets were considered necessary to adequately characterise the salinisation processes of in each conceptual hydrogeological model. The first, "constants", determine the inherent susceptibility of the catchment to salinisation. The second dataset type, "variables", can be used to determine whether salinisation will actually occur in catchments with the appropriate inherent conditions for salinisation. These datasets would form the basis of a hierarchical catchment classification system.

Implications

Recommendations were made to develop a national framework to guide management effort and funding allocations, based on the fifteen models identified in the project, and the critical datasets identified for characterising salinisation processes. Project specifications have since been developed for a large project to identify the occurrence of the fifteen catchment types across the continent, and to predict in detail their characteristic responses to salinisation management approaches. Funding is now being sought for this project.

RIRDC Project No: AGS-1A

Researcher: Jane Coram

Organisation: Australian Geological Survey Organisation, P.O. Box 378 , CANBERRA ACT 2601
Contacts: Phone: (02) 6249 9304, Fax: (02) 6249 9970

Aleppo pine low rainfall farm forestry

Objective

To evaluate the potential of the Aleppo pine group for profitable low rainfall farm forestry
To evaluate the suitability of sawn and treated round Aleppo pine timber for structural and other uses.
To promulgate findings to landholders and investors, if warranted.

Background

A projected world shortage of utility timbers offers an opportunity for extension of plantation pine forestry into the lower rainfall area farmland provided growth rate, stem form and timber properties are sufficient to justify the diversion of land from existing farm activities. Aleppo pines, particularly Pinus halepensis and P. brutia, native to Mediterranean countries with similar climates to much of southern Australia, are grown for timber there and are thus potentially suitable candidate species.

Research

Aleppo pines have been surveyed in farm and forest situations in appropriate climatic areas in southern Australia to determine most suitable provenance material and to relate growth and other acceptability criteria to growing conditions.

Basic wood properties of the Aleppo pine group have been measured in an extensive test program. Density, stability and mechanical properties have been assessed in comparison with Pinus radiata.

PIRSA’s "ReVal" spreadsheet for gauging economic cost benefits of farm revegetation projects has been applied to numerous scenarios involving planting configuration, growth rate, agricultural gains and losses, wood returns and financial considerations.

Outcome

Observations have confirmed that P. brutia has better form than P. halepensis making it the preferred choice for timber production, but as examples of P. brutia in the field are scarce, a series of trial plots have been recommended to establish its growth characteristics with more certainty.

Best conditions for low rainfall agroforestry, not surprisingly, generally correspond to those best for most other farming activities. Preferred conditions include Mediterranean climate, 450mm or more mean annual rainfall, supplementary ground water, deep friable soils, best forest establishment practices and large woodlot plantings to minimise proportion of stunted perimeter trees. Good silvicultural practices, which may include pruning, must be maintained throughout.

Aleppo pine timber at least matches P. radiata in stability and mechanical properties. Previous poor reports about these characteristics are unjustified, provided the problem of knots is addressed by good silvicultural and timber processing practices.

Assessment of economic prospects for low rainfall farm woodlot plantings is complex, involving numerous factors. Planting large woodlots in expectation of positive financial returns without expert advice is unwise and even then investment remains risky. However, prospects for success are improved when planting conditions conform with recommendations, mean annual increment (MAI) in timber production approaches 15m³/ha/yr and all thinnings as well as clearfell are sold at commercial rates. Considering woodlotting as a continual long term farm enterprise extending down the generations provides a scenario with much improved profitability. This can be further enhanced by incorporating timber felling and carting and possibly sawmilling into enterprise activities.

Implications

Further trialing of P. brutia in a range of farm situations in the favoured zones is needed to verify adequate growth and stem form characteristics. Provided adequacy of these characteristics can be substantiated low rainfall farm forest plantings can be justified under particular financial circumstances which must be assessed on a case by case basis.

Trialing of P. brutia in salinisation sites is especially recommended as there is evidence that the related P. halepensis performs much better than P. radiata in these situations.

RIRDC Project No: RST-1A

Researcher: Peter C Crammond

Organisation: RST Technology Pty Ltd

PO Box 224
JAMESTOWN SA 5491

Contact: Phone: (08) 8664 1841, Fax: (08) 8664 1841 E-mail: karamundc@bigpond.com

Project Title

The impact of trees and fodder shrubs on soil acidification

Objective

To assess the role of trees and fodder shrubs in managing acid soils and understand how the choice of species may influence the rates of soil acidification.

Background

Soil acidification is a major form of land degradation in Australia, particularly serious in the more productive parts of the country, areas with above 500 mm rainfall. The consequent cost of lost production exceeds $ 300 million annually. Soil acidification is a natural process and occurs at a slow rate during the weathering of soils. It is accelerated by agriculture, horticulture and forestry. The most acidifying systems are those where large amounts of biomass are removed from the land, where the recycling of nutrients is inefficient and nitrate is allowed to leach from the soil or where ammonium-based fertilisers are used. Trees might modify rates of soil acidification through capturing nutrients at depth in the soil and recycling them to the surface in litter, through the production of organic anions which represent stored alkalinity because they consume protons and raise the pH when they decompose, and through the production of substances which chelate cations and allow them to leach as neutral complexes. An important question is how much tree species differ in this regard.

Research

There were four major components to the research. Firstly, the differences in mineral composition and ash alkalinity of leaf litter from a range of species (both native to Australia and exotic) was measured and the influence of environmental factors was examined. Secondly, a procedure was developed to measure the cation complexing ability of water soluble components of leaf litter, and used to assess the litter set. Thirdly, laboratory incubation and leaching column studies were conducted to examine the effects of litter added to acid soil on soil pH and cation content. Lastly, plantations of known age of some representative species were identified and sampled to assess differences in soil properties between the plantation area and adjacent land use.

Outcome

There was significant variation in the ash alkalinity of litter from different tree species. Of the 28 species tested the native Melia azederach had the highest ash alkalinity while some eucalypt and acacia species and radiata pine had low ash alkalinity. Exotic deciduous species were generally higher than the native species. Ash alkalinity was highly correlated with calcium content, was lower in young leaves than in mature leaves and, although it was affected to some extent by soil nutrient availability, genetic differences were of major importance.

There were large differences between species in cation complexing ability and column studies suggested that this property would be influential in leaching of soil cations.

Studies in the field with plantings of white cedar, poplar, river gum, tagasate, radiata pine and cork oak, each compared with pasture or ley farming showed that the soil under trees was generally less acid than adjacent soil, and had higher exchangeable cations and lower extractable aluminium. However, at one site under oak trees the soil had acidified considerably and had lower base status and clay content. Cork oak litter has high cation complexing ability which may have facilitated leaching. Also the site was sloping, allowing litter to be washed or blown down hill causing losses of alkalinity.

Implications

The potential benefits of trees to soils vary widely with species. The risk of loss of nutrients and alkalinity contained in the trees also varies with species and with site. Trees with high ash alkalinity, for example, would ‘pump’ more nutrients to the surface and raise pH there, but at the same time expose more to potential loss. The two properties, ash alkalinity and cation complexing ability of the water extract of the litter can be used to help assess the suitability of species for particular sites.

RIRDC Project No: CSP-4A

Researcher: P J Randall

Organisation: CSIRO Plant Industry,

GPO Box 1600

CANBERRA ACT 2601

Contacts: Phone: (02) 6246 4911

Fax: (02) 6246 5000

Project Title

Agroforestry from existing timber resources on the Northern Tablelands

Objective

To provide private landholders with relevant information from demonstration farms on the economic and market potential for timber products sourced from existing timber resources on their land
To provide an assessment of the ability of this resource to generate the cash-flows required to establish new farm forestry plantations.

Background

Much agroforestry research has focussed on tree planting. However, the long time frames and early negative cash flows associated with plantations are a deterrent to many landholders. This is particularly the case on the Northern Tablelands of NSW where growth rates for hardwoods are low and markets for thinnings poorly developed. Yet, many landholders have existing native forests which might be managed and logged sustainably. This study examines the options for managing native timber on Tablelands farms.

Research

Four case study farms were selected to model the financial effects of managing existing native timber. A 60 year whole-farm budgeting model (AGROFARM) was developed which describes in detail the physical and financial aspects of the farm business and the proposed native timber management enterprise. Management regimes and timber volumes were specified with the assistance of State Forests of NSW foresters and input from local sawmillers. For each case study farm, aerial photographs were used to assess existing tree cover and, in conjunction with the landholder, the total forested area to be managed was calculated. A number of options for timber production were considered including selling at stumpage prices to local mills, selling green-sawn timber sawn on-farm and drying/dressing.

Outcome

The financial performance of adding a native timber enterprise to the case study farms was heavily dependent upon the per hectare costs of spacing/thinning. Where spacing costs were in the order of $200 per hectare, selling timber at stumpage prices could not be justified and the majority of the economic benefits were derived from the increased stocking capacity in the thinned forest areas. In most cases, a doubling of harvest volumes would be required to offset this thinning expenditure.

However, while cypress pine may incur spacing costs of this magnitude, the low stem density amongst eucalypt forests in the region means spacing costs are likely to be much lower.

Where timber was value-added on farm (either sold as green-sawn or dried and dressed), spacing costs of $200/ha could be absorbed and the venture was far more financially attractive. This was particularly the case where stocking capacity benefits were captured. As spacing costs are likely to be much lower in most cases, selling value-added timber is the most profitable option.

The cash flows generated from all forms of existing timber production fell significantly short of the funds required to establish new hardwood or softwood plantations.

A key information gap was identified - the growth response of Tablelands forests to spacing/thinning is unknown and needs to be measured for a more accurate financial analysis to be performed. Sensitivity analysis on harvest volumes was used to account for this problem.

Implications

The relatively low stumpage prices offered by Tablelands sawmills indicate that if existing timber sales are to represent anything more than marginal opportunistic income, some form of value-adding will be required. If this avenue is pursued, farmers will have to provide a consistency in the supply and quality of sawn timber and need additional marketing power to access markets. Inevitably, this will require landholder networks. This project has already resulted in the formation of a fledgling network which is being coordinated through the New England Regional Plantation Committee.

Further work on native forest responses to thinning is required. There is also concern over the new Native Vegetation Management Act and the future ability manage and sustainably log native timber resources.

RIRDC Project No: CAR-1A

Researcher: David Thompson

Organisation: Centre for Agricultural & Regional Economics Pty Ltd,

215 Mann St,

Armidale NSW 2350

Contacts: Phone: (02) 6771 3833

: Fax: (02) 6771 3528

E-mail: care@northnet.com.au

Project Title

Plantation Production of Australian Hardwood Timber for Use in Scrimber and Assessment of the Quality of this for Scrimber Production

Objective

To investigate early, rapid growth of Pinus radiata and of six hardwood species. The latter were selected for their potential to grow in the region and for their wood properties; straight grained wood of moderate density that has good workability, low durability and high moduli of rupture and of elasticity.

Background

The project was conceived to provide information on the possibility of using fast-grown hardwood species to produce quality scrimber. Subsequent non-commercialisation of this process has changed the emphasis to providing growth and economic assessment information on several hardwood species in relation to one another and to the local forest industry standard Pinus radiata.

Research

Trees were grown from seed of the anticipated most productive provenances of Acacia mearnsii, Casuarina glauca, Eucalyptus fraxinoides, E. globulus, E. grandis, E. saligna and from the typical genotypes of Pinus radiata used in the region at the time. Stem growth was measured every half year. At the end of the project an economic assessment was carried out to predict anticipated returns, using mensurational models to predict future growth.

Outcomes

All species other than Casuarina glauca grew well. The economic assessment indicated that for a range of indices P. radiata offers the best returns, but that some treatments of E. grandis could also produce positive returns. Productivity and returns of hardwood species would probably improve by selection and breeding, as carried out with P. radiata.

Implications

Financial returns are unlikely to be sufficient to support a viable industry with the techniques and most of the species x treatment combinations used in this project, at least with the current state of genetic selection and breeding.

RIRDC Project No: CSF-38A

Researcher: Dr. David Sheriff

Organisation: CSIRO Forestry and Forest Products

Plantation Forest Research Centre

PO Box 946

MOUNT GAMBIER SA 5290

Contacts: Phone: (08) 8721 8112

Fax: (08) 8723 9058

E-mail: david.sheriff@ffp.csiro.au

Project Title

Strategic agroforestry options to control and prevent land degradation

Objectives

To predict the effects on salinity risk of different revegetation strategies using perennial deep-rooted vegetation and therefore determine optimal revegetation strategies. In the long term this capability will contribute to efficient and effective establish of perennial deep-rooted vegetation to control or prevent salinisation in agricultural catchments.

Background:

Changes in landscape hydrology, as a result of agricultural development, have led to extensive salinisation of productive soils. Revegetation with trees and other deep-rooted perennial vegetation is seen as one way of reversing the changes in hydrology that contribute to soil salinisation. It is estimated that in 1990 farmers planted 10 million trees in Western Australia but that only a small proportion of them will result in the desired changes in landscape hydrology.

Research

There were three main components to the project. Firstly, the assessment of airborne electromagnetics for the hydrogeological catchment mapping, with particular reference to the parameterisation of numerical groundwater models. Secondly, a review of the available data on the water use of trees and other woody perennial vegetation in the Mediterranean regions of southern Australia. Thirdly, the application of an "industry standard" groundwater model to the assessment of different revegetation strategies on salinity risk for a case study agricultural catchment.

Outcomes

Given the current state of development of technology, airborne electromagnetic data is unsuitable for hydrological mapping at the catchment scale. The best use of airborne electromagnetic data is qualitative analysis of anomalous areas of regolith salt storage at the regional scale.

All available tree water use data, including previously unpublished data, has been critically examined and a simple predictor of annual tree water use in the presence of shallow, saline groundwater has been developed.

A computer based groundwater model has been used to assess the impacts of a range of revegetation strategies on the salinity risk of a case study agricultural catchment. Guidelines for applying the model to other agricultural catchments in Western Australia have been developed.

Implications

Agriculture Western Australia has continued to co-operate with the developers of airborne electromagnetic technology and other state and national agencies in the use and interpretation of this source of data. The groundwater model used in the case study catchment is in operation by Agriculture WA in assessing water management strategies developed by catchment groups in the Blackwood Catchment. Automation of the data transfer between Agriculture WA’s GIS and the model has been improved.

RIRDC Project No: DAW-35A

Researcher: Paul Raper

Organisation: Agriculture Western Australia

PO Box 1231,

BUNBURY WA 6230

Contacts: Phone: (08) 9780 6295

Fax: (08) 9780 6136

Project Title

Policy reforms for agroforestry – post NPAC: an investigation of reforms to overcome impediments to agroforestry

Objectives

To identify current policy impediments to agroforestry;
To develop recommendations for targeted and comprehensive reforms to government policies and industry practices which currently impede agroforestry; and
To identify adoption of effective agroforestry policy reforms, in line with the National Forest Policy, the NPAC Recommendations, and the Industry Commission Inquiry.

Background:

The benefits of agroforestry are widely acknowledged but factors impeding adoption of agroforestry have been difficult to overcome. While recent policy initiatives endorse farm forestry in principle, actual progress has been slow in Australia (with a few exceptions). This project used a consultative approach to assess impediments to farm forestry and identify the relevant policy reforms.

Research

In early 1996 a discussion paper which summarised major impediments to farm forestry, and opportunities for overcoming them was distributed widely. Workshops with a cross section of interests were held in each State to canvass the issues and opportunities identified. Literature, field days, field trips and seminars were also used to further investigate economic, environmental, and cultural aspects of farm forestry. The project involved key industry and government personnel in the process of identifying necessary reforms, and thus may catalyse change.

Outcomes

The Final Report documents has 26 principle findings and makes 22 recommendations which describes and analyses 20 major impediments to farm forestry in Australia and, uses the analysis to identify the necessary policy reforms.

Implications

Farm forestry has significant potential in Australia but much more could be done to create a supporting policy environment. Clarifying the role of government is critical. Direct subsidies for farm forestry production are not advocated, but comprehensive policy reforms are overdue. Farm forestry appears to have remained a low priority within the forest policy reforms processes of the 1990s and Australia continues to miss out on the many important opportunities as a result.

Publications

‘Creating a viable farm forestry industry in Australia – What will it take?' Final Report (130 pp.)

‘Creating a viable farm forestry industry in Australia – What will it take?' Discussion paper

RIRDC Project No: AHM-1A

Researchers: Jason Alexandra and Michael Hall

Organisation: Alexandra & Associates Pty Ltd

Hazeldean Rd,

ELLINBANK VIC 3820

Contacts: Phone: (03) 5627 8420

Fax: (03) 5627 8255

E-mail: jasona@sympac.com.au

Project Title

Strategies for regional farm forestry

Objectives

To work with key farm forestry stakeholders to evaluate selected farm forestry projects;
To review available socio-economic research of factors affecting regional farm forestry;
To investigate the principles and practices of effective market links between small-scale growers and industry.

Background:

There has been considerable government investment in regional farm forestry development across Australia since the early-1990’s. However, there had been few systematic approaches to evaluating the effectiveness of such investment and little information available to inform emerging regional projects of previous lessons. This project worked with staff from the Department of Primary Industries and Energy’s Farm Forestry Program and other key farm forestry participants to assess 27 projects developed under this national program. The lessons from this evaluation were used to inform farm forestry program and project managers, and subsequent components of this research project.

While farm forestry in Australia is promoted as having the potential to provide economic, environmental and social benefits at the farm, regional and national levels, there has been little understanding of the likely socio-economic impacts. This project conducted a review of Australian and international literature to identify some important issues to assist a range of participants better understand the socio-economic context in which farm forestry is developing.

Previous research highlighted that limited progress had been made in developing the effective, long term linkages between landholders and industry critical to the emergence of viable regional farm forestry industries. However, there has been little investigation of this topic.

Research

The researchers used accepted social science methods to: evaluate the FFP; identify key socio-economic issues; and investigate market links between small-scale growers and industry. Such methods involved document studies, semi-structured interviews; and focus groups; and a mailed survey. The project operated during July-1995 and July-1997.

Outcomes

The project outcomes were disseminated through three research reports:

Curtis, A. and Race, D. (1995). Review of Department of Primary Industries and Energy National Farm Forestry Program. 2 vols. Report No. 40, The Johnstone Centre - Charles Sturt University: Albury, NSW.

Curtis, A. and Race, D. (1996). A review of socio-economic factors affecting regional farm forestry development in Australia. Report No. 69, The Johnstone Centre - Charles Sturt University: Albury, NSW.

Curtis, A. and Race, D. (1997). Links between small-scale growers and industry: Lessons from farm forestry development in the Green Triangle, Tasmania and Western Australia. Research Report submitted to Rural Industries Research and Development Corporation , publication 98/41.

These reports are available from the publishing organisations. Also, several refereed journal articles, conference papers, and field day notes were produced by the researchers.

Implications

The project has made a positive contribution to developing strategies for regional farm forestry development. The researchers regularly exchanged information with other farm forestry participants - landholders, government agencies and industry. Project findings influenced development efforts, particularly in relation to: