Targetted Strategies for Implementation of Farm Forestry
 

Project Title	ANU forestry market report project, 1998-99
RIRDC Project No.:	ANU-32A
Researcher:	U.N. Bhati
Organisation:	Department of Forestry The Australian National University CANBERRA ACT 0200
Phone:	02 6249 3220
Fax:	02 6249 0746
Email:	un.bhati@anu.edu.au
Objectives	The objective is to contribute towards creating more informed forest product and input markets in Australia, particularly for small scale forest growers. The objective is being achieved by preparing and disseminating nationally a quarterly market report on forest products and inputs.
Background:	Lack of readily available market information from an independent source has long been recognised as a major impediment to farm forestry in Australia. With the intention of filling a part of this crucial information gap, ANU Forestry held consultations with Australian Forest Growers and other industry groups. Following their endorsement, the project commenced in June 1997 and has been continuing since.
Research	As planned, four market reports were prepared and disseminated in 1998-99. Their titles and publication dates are as follows: woodchip markets and prices, June 1999; cost of log transport, March 1999; log exports, December 1998; and stumpage, September 1998. In addition to dealing with the stated topics, the reports provided data on actual stumpage received by small scale growers in various regions of Australia. The stumpage prices were presented along with month and year of log sale; region and State where logs were harvested; log type, species and volume; and distance from the place of harvest to mill or wharf. The reports were disseminated through industry magazines such as Agroforestry News, Australian Forest Grower and Australian Farm Journal, ANU Forestry web site and the internet networks.
Outcomes	To further create awareness about the market reports and to receive invaluable face-to-face feedback, presentations were made at selected national, regional and local meetings, workshops and conferences. Written and spoken feedback from readers and others indicates that the project provided impartial and useful market information. Representatives of stakeholders reviewed the project at a meeting in July 1998. Also, a progress report on the project was submitted to the RIRDC/ LWRRDC/ FWPRDC Joint Venture Agroforestry Program later in 1998. Both re-endorsed the project and its progress.
Implications	The project has prepared and disseminated four quarterly market reports in 1998-99. It has thus achieved its objective for the year. However, looking beyond 1998-99, much remains to be done for creating more informed forest product and input markets for small scale growers. ANU Forestry will strive to achieve these results and seeks support from JVAP and others in pursuit of this goal.

 
 

Project Title	Farm forestry market information service
RIRDC Project No.:	DAW-86A
Researcher:	Peter P Eckersley
Organisation:	Agriculture Western Australia  PO Box 1231  BUNBURY WA 6230
Phone:	+61 8 9780 6204
Fax:	+61 8 9780 6136
Email:	peckersley@agric.wa.gov.au
Objectives	To design and initiate a market information service for landowners investing in and managing farm forests.
Background:	A credible robust and accessible service could address many of the issues identified in the strategic imperatives of Vision 2020, which is a dominant national policy influence on the forest sector. The efficient provision of timely valued information was highlighted as a critical requirement for an expanded plantation and farm forestry industry. In Western Australia, the Farm Forestry Task Force also identified the need for independent farm forestry market information.
Research	FORTECH (WA) were engaged to design a Farm Forestry Market Information Service (FFMIS). The Kondinin Group assisted FORTECH with specific communications issues. The project identifies and analyses existing market information services available both domestically and regionally relevant to Australia. It describes a survey of potential users. It recommends structure, design and functioning of a FFMIS. Trends in farmers’ use of information technology are analysed. The report summarises current information sources available and directly relevant to Australia. It briefly evaluates the ANU Forestry Market Report for its information sourcing, interpretation and dissemination.
Outcomes	The analysis of market information on forest products indicates that there are two distinctly different scenarios, varying according to the market source, being either international or domestic. The international market is typified by the availability of extensive and specialised market information. In contrast, market information for the domestic market is generally limited in availability and depth. The domestic Australian forest product market structures are strongly regionalised, but Australian domestic timber prices are likely to become increasingly influenced by international wood prices. Client survey responses indicated that the structure and format of market information service for WA would be equally applicable to other regions of Australia. Users are particularly interested in determining information relevant to their local situation, and are seeking information in an analysed and described form. Users expect to use a variety of sources of market information, relying less on word of mouth and more on informed reliable sources. Preferred mechanisms of delivery are post, magazine and internet, and either consultants or government agency staff for face-to-face contact. Users are willing to pay for the service. The payment structure should match user requirements.  The report identifies target users, information to be provided, delivery methods, skills required, systems management, review process and a fee structure. The report also outlines an approach for its implementation.
Implications	There is an opportunity for a state or national body to take the lead in implementing the concept developed in this report. Key stakeholders must jointly commit to fund development of a business plan for a FFMIS.

Sustainable Use of Natural Resources
 

Project Title	Integrating Farm Forestry and Biodiversity
RIRDC Project No.:	AAC-4A
Researcher:	Mark Kelly
Organisation:	Fortech
Phone:	02 6248 6900
Fax:	02 6248 6999
Objectives	To evaluate whether and how biodiversity conservation objectives can be incorporated into commercial farm forestry developments.
Background:	Tree establishment on farmland has the potential to increase the sustainability and productivity of farming. Farm forestry provides a commercial incentive for tree establishment. Integrating biodiversity conservation objectives with commercial farm forestry developments would provide an additional benefit. This project was initiated to evaluate whether and how this integration may be feasible.
Research	This research included the following major activities:  a review of the major legislation, regulations and government policies, including international agreements, that address or affect biodiversity protection in Australia a review of scientific literature to assess what is known about the effects of farm forestry on biodiversity the beneficial effects of development of commercial farm forests and plantations on flora, fauna and catchment values discussions with farm foresters to identify opportunities for practical integration of farm forestry and biodiversity case studies of farm forestry experience consideration of design of farm forests and adoption of management practices that may protect and/or increase biodiversity
Outcomes	The review of scientific literature showed much research that enables comparison of biodiversity values of planted forests with native forests but little information on the biodiversity impacts of planted forests compared to agricultural land uses.  Intensively managed plantations with a narrow genetic base have little biodiversity value and can have adverse effects if exotic tree species invade adjoining native vegetation. However, there are indications that development of farm forests and plantations on farmland can benefit flora, fauna and catchment values and can therefore help protection of biodiversity.  There is a wide range of legislation, regulations and policy at commonwealth, state and local government levels that deal with or are relevant to farm forestry or biodiversity in some way. Some of these can control practices that may reduce biodiversity. Others, especially land use controls, can act as disincentives to development of farm forestry or plantations.
Implications	A number of initiatives were identified. These include: development of designs, e.g., patchiness in species and age classes and inclusion of indigenous or habitat species development of more environmentally benign management practices consideration of farm forests in property management plans research and development to focus on biodiversity impacts of farm forests compared to agriculture more explicit recognition of public and private costs and benefits of biodiversity enhancement

Project Title	Sustainable Hardwood Production in Shallow Watertable Areas
RIRDC Project No.:	CSI-3A
Researcher:	Dr Rob Vertessy
Organisation:	CSIRO Land and Water, Canberra Laboratories GPO Box 1666,  CANBERRA, ACT 2601
Phone:	02 6246 5790
Fax:	02 6246 5845
Objectives	To develop and validate a model describing salt and water dynamics underneath eucalypt plantations growing in shallow watertable areas.
Background:	A potential option for watertable control in shallow watertable areas is the establishment of tree plantations. The trees would provide a direct financial return to the grower through wood production, and lead to lowered watertables through groundwater being used for transpiration. The feasibility of this concept depends on achievable growth rates (closely related to tree water-use), the extent of the beneficial effect of the trees on surrounding agricultural land (watertable control benefits) and on the sustainability of this system (potential for salt accumulation beneath the trees through concentrated water uptake). The net benefits and potential problems are likely to be site specific. The physical characteristics at a location (such as soil permeability, groundwater salinity, and depth to groundwater) combine with climatic conditions to determine how the trees interact with the groundwater system. What is desirable is that the trees’ use of groundwater be managed to balance the objectives of minimising salt accumulation, lowering the groundwater table, and maximising growth rates.
Research	The work conducted in the project was divided into two main activities, namely field experimentation and model development. The objective of the field work was to improve our understanding of the processes operating at a site felt to be representative, and assemble a database of observations of key flow and transport processes which could be used to test the model developed. The field work was conducted at a 20 year old eucalypt plantation near Kyabram in central Victoria.  The model developed was used to ask the following questions: Are trees able to control shallow watertables caused by the combination of irrigation and the change from deep rooted native vegetation to shallow rooted pastures and crops?  If so, what is the spatial extent of this watertable control?  How sustainable is this system, considering the possibility of salt accumulation taking place underneath the trees?  How do the trees respond to different soil and groundwater conditions?  How would irrigating the plantation or harvesting it earlier affect the yield and the watertable response?
Outcomes	The model developed, called Topog_Dynamic, uses physical equations to simulate water and salt movement over the land surface, into the soil, through the soil and groundwater system, and back to the atmosphere via evaporation and transpiration. It also uses biophysical principles to simulate the growth of plants (ie. trees, crops and grasses) and the effect that plants have on mediating water and salt movement. The growth of plants is, in turn, affected by the site water and salt balance, so feedbacks between vegetation growth and hydrology are represented.  A site with conditions like those at Kyabram appears to have a time scale of about 20 years before the effects of salt accumulation and water limitation caused by the low permeability become apparent. This corresponds to the current age of the plantation at Kyabram, and indicates that the plantation growth is declining. A general conclusion from the modelling work is that if the plantation density is sufficiently high that evaporative demand exceeds infiltration, the trees will use water from a shallow watertable for transpiration. Salt accumulation will occur and the magnitude of that accumulation will be directly related to the net groundwater discharge (difference between transpiration and infiltration) and the groundwater salt concentration. The plantation groundwater usage will decline as the watertable falls and as salt accumulation increases, with the result that the magnitude of the depression in the watertable will also decline. This process will also result in plantation growth slowing down. If salt accumulates to the point where the trees can no longer use groundwater, growth would be limited by rainfall availability.
Implications	Watertables can be lowered significantly by trees. However, this will be accompanied by salt accumulation in the root zone which will eventually limit growth and water use, resulting in the watertable rising again. Occasional irrigation or leaching events may alleviate this. Wood yield from a plantation with a shallow watertable may be acceptable, but is unlikely to be high without additional water. The trees can therefore be regarded as biological salt accumulation basins or irrigated crops, and need to be managed accordingly.
This project was jointly funded by the MDBC

Project Title	The effect of salt on wood and fibre formation in eucalypts
RIRDC Project No.:	UM-18A
Researcher:	Stephen J Catchpoole & Stephen M Read,
Organisation:	School of Forestry University of Melbourne CRESWICK VIC 3363
Phone:	03 53 214177
Fax:	03 53 214194
Email:	s.read@landfood.unimelb.edu.au
Objectives	To determine whether irrigation of blue gum (Eucalyptus globulus ssp. globulus) with saline groundwater effects important wood and fibre properties.
Background:	Tree planting is one approach for lowering the high saline water-tables that affect large areas of agricultural land in Australia. Such plantations could become a significant fibre source for the pulp and paper industry, but it is not known whether growth in salt-affected environments influences fibre properties that are important in paper production.
Research	This work thus examined blue-gum trees grown in 2 trials near Shepparton, Victoria, irrigated with pumped saline ground water; and in pot trials at Creswick, Victoria, where trees were exposed for 10 weeks to higher levels of salt. The field trials involved measurements on trees at 1.5-3.5 years after planting, while the pot trials used trees at 1.5 years of age.
Outcomes	Tree growth in the field in the first 3.5 years after planting was unaffected by moderately saline soils with an ECe value (a measure of salinity) of up to 4.7 dS m-1, and there were no consistent increases in leaf ion content, wood basic density or any fibre morphological parameter. Exposure of pot-grown trees to higher levels of salt for a briefer period decreased growth slightly, reduced water use, and gave marked increases in leaf ion contents but again no changes in any fibre morphological parameter. Moderate levels of soil salt that do not significantly affect growth of blue gum thus also have no measurable effect on fibre properties, at least in trees up to 4 years old.
Implications	The main implication is that establishment of blue-gum plantations on sites irrigated with saline groundwater appears, at least initially, to be a feasible proposition, with no changes in the wood that might reduce fibre quality.

Optimised Productivity of Crops and Pastures
 

Project Title	Modelling crop growth and yield under the environmental changes induced by windbreaks
RIRDC Project No.:	CSC-52A
Researcher:	Peter Carberry & Holger Meinke
Organisation:	Agricultural Production Systems Research Unit CSIRO Tropical Agriculture & Queensland DPI 203 Tor Street,  TOOWOOMBA QLD 4350
Phone:	07 4688 1377
Fax:	07 4688 1193
Objectives	In order to answer the question "Why do windbreaks work?", this project addressed the hypothesis that windbreaks influence the crop water and energy balances, thence affecting crop temperature and plant growth. To achieve this goal, the project objectives are: To translate the impact of measurable differences in microclimate induced by windbreaks into physiological changes in crop growth, development and yield through the application of validated crop simulation models to data from windbreak experiments conducted at selected locations throughout Australia.  To quantify the potential benefits and the likelihood of windbreak effects on crop production through an economic analysis of crop yields predicted for the historical climate records at selected sites and for the expected range in microclimatic change induced by windbreaks.
Background:	Convincing evidence exists for long-term benefits of retaining or planting trees on farms to rehabilitate land and protect the soil from erosion or salinity problems. The incentive for farmers to plant trees would increase, however, if there was widespread confirmation of recent reports of enhanced crop yields in the short-term due to tree windbreaks. In recent reviews of the effects of windbreaks on farms, it has been contended that substantive evidence on the relationship between windbreaks and crop productivity is still required. It is in response to the need for such evidence that this project was initiated. The project was part of the National Windbreak Program.
Research	This project developed and used crop and micrometeorological modelling capabilities to explore potential benefits and the likelihood of windbreak effects on crop production in Australia. The APSIM systems model was specified to simulate crop growth under the environmental changes induced by windbreaks and subsequently used to simulate the potential benefits on crop production at two actual windbreak sites and 17 hypothetical sites around Australia.
Outcomes	With the actual windbreak sites, APSIM closely simulated measured crop growth and yield in open-field conditions. However, neither site demonstrated measurable windbreak impacts and APSIM simulations confirmed that such effects would have been either non-existent or masked by experimental and climatic variability in the years under study.  For each year of the long-term climate record at 17 sites, APSIM simulated yields of relevant crops for transects behind hypothetical windbreaks that provided protection against all wind. When wind protection from any direction is assumed, average yield increases at 5H ranged from 0.2% for maize at Atherton to 24.6% for wheat grown at Dalby, resulting in gross margin changes of -$14.79/ha/year and $24.13/ha/year respectively for a 10 m high windbreak and 100 ha paddock. Averaged across all sites and crops, the simulations predicted a 10% yield advantage at 5 H for protection from wind in any direction, resulting in an average gross margin increase of $0.56/ha/year. However, at none of the sites with available data, were there positive average gross margin impacts when a more realistic scenario was assumed (namely wind originating within a 90° arc perpendicular to a hypothetical windbreak).
Implications	In conclusion, APSIM simulation and economic analyses indicated that yield benefits from microclimate changes could only partly offset the opportunity costs of positioning tree windbreaks on farms.

 
 

Project Title	Trees for wood and animal production in Northern Australia
RIRDC Project No.:	CSC-58A
Researcher:	Brian Lowry
Organisation:	CSIRO Tropical Agriculture,  120 Meiers Road,  INDOOROOPILLY 4068.
Phone:	07 32142840
Fax:	07 32142881
Objectives	To demonstrate the feasibility of more sustainable and productive farming systems through the use of trees that promote animal production and also yield a valuable timber crop.
Background:	This project is based upon the existence of certain trees in northern Australia that can yield cabinet timber but which also, grown at wide spacings in pasture, could address the nutritional constraints of the northern grazing industry by dry season fall of edible leaf, flower or pod, and by promotion of growth and quality of the sub-canopy grass. A previous review (RIRDC Publication 97/73) highlighted the siris tree (Albizia lebbeck) for having all these attributes and noted other species worth investigating further. This project sought more data on siris and on other species with potential for dual purpose agroforestry.
Research	Naturally fallen leaf, flower or pod was collected from the species of interest and analysed for nitrogen and fibre. According to the amount available, feeding experiments were conducted to determine voluntary intake and digestibility, together with in vitro evaluations, including co-fermentation with dry-season grasses. Annual growth increments were obtained for species of interest on a variety of locations, and dry-season phenology recorded. There were comparative measurements of dry matter and quality of subcanopy grass. Siris trees were pruned for future evaluation of the potential for producing short clear logs from open-grown trees.
Outcomes	Potential for establishing siris was enhanced by recognition of areas of volunteer establishment, and, although results from purposeful planting have been variable, some high growth rates are occurring. Only siris showed significant contributions from fallen flower, and also had the highest production of pods. In general results supported the concept that dry-season deciduous leaf fall could be utilised by livestock but showed inter alia that leaf had to be eaten soon after falling; deterioration on storage compromised a feeding trial with Gmelina arborea leaf. For some species there was evidence for positive associative effects when fallen leaf was eaten with dry-season grass. In particular soluble constituents in fallen siris leaf promoted cellulose digestion in vitro. In addition to previous observations with siris, isolated trees of Albizia canescens, A. procera, and Tipuana tipu had enhanced growth of Panicum maximum cv Green panic in the sub-canopy area, leading to increased pasture quality and, usually, dry matter production. Although not a legume, Melia azedarach (white cedar) sometimes also had enhanced sub-canopy grass. Paraserianthes toona (red siris, Mackay cedar) was strongly inhibitory, probably due to its growth habit. The results suggested A. procera would have considerable value in some sub-coastal areas. They also drew attention to Albizia canescens as a little-known highly-undervalued native species. It is highly palatable, promotes sub-canopy grass, and can be found in open eucalypt woodland. It is widely distributed in northern Australia yet apparently nowhere common. It is almost unknown in Queensland today yet was one of the recognised Queensland timbers last century.
Implications	The results suggest that over a large area of northern Australia landholders have the potential to diversify into wood production while also creating a more productive pastoral system. The potential is even greater if initial establishment costs can be covered by accrediting plantings for carbon sequestration.

 
 

Project Title	The impact of trees on winds, temperatures and evaporation rates in farmlands
RIRDC Project No.:	CSM-1A
Researcher:	Helen A. Cleugh
Organisation:	CSIRO Land & Water GPO Box 1666 CANBERRA, ACT 2601
Phone:	02 6246 5574
Fax:	02 6246 5560
Objectives	To form integrated, quantitative assessments of the effects of trees on farm microclimates, by using field measurements, wind tunnel data, physical theory and agronomic understanding to develop and test predictive models for wind, temperature, evaporation, soil moisture and plant responses to windbreaks.
Background:	Trees on farms have a vital role in ameliorating a range of land degradation problems such as wind erosion, waterlogging and salinity. Trees are also believed to increase agricultural productivity through their effect on the microclimate, especially via reduced wind speeds; moderation of crop and soil temperatures; and reduced evaporation. A difficulty in quantifying the effects of trees on farmed landscapes is that the processes and mechanisms involved are highly interactive and often quite specific to the climate regime, soil type and farming practice – limiting simple extrapolation from one experience or set of results. Both a predictive capacity and an integrative view of the role of trees are thus needed to assess the benefits and costs of trees.
Research	This research project is part of the National Windbreak Program whose aims were to develop an understanding of the interaction between windbreaks, microclimate and crop and pasture growth; to provide an integrated and quantified assessment of the response of agricultural systems to windbreaks; and to develop a predictive capacity to enable windbreak effects to be generalised.  The specific objective of this research component was to quantify the effect of porous windbreaks on microclimates (wind, temperature and humidity) and evaporation fluxes using a combination of wind tunnel experiments, field measurements and numerical modelling. Wind tunnel experiments were conducted to investigate the effects of: (a) multiple windbreaks on airflow; (b) windbreak porosity on microclimate and evaporation fluxes oriented both normal and (c) oblique to the flow; (d) of short windbreaks and windbreaks on hills. A complementary set of field measurements enabled validation of the wind tunnel experiments (a – c); quantified the diurnal variation of shelter effects on microclimates; and investigated the impact of wind shelter on plant water-use.
Outcomes	The windbreak porosity and height determine, respectively, the level and downwind extent of wind protection. A sheltered zone extends from about 5 windbreak heights upwind to over 20 windbreak heights downwind of the windbreak. The extent and shape of this sheltered zone does not vary with porosity – at least for the range of porosities used in our wind tunnel experiments, which matched the range for most typical tree windbreaks used on farms.  Near-surface temperatures are increased slightly in this sheltered zone - the peak increase for the densest windbreak was » 2oC under conditions typical of a crop at midday in spring or early summer in SE Australia. This temperature increase mirrors the pattern of wind shelter, at least to about 10 windbreak heights, so the greatest increase is found for the densest windbreak and the peak temperature occurs where wind speeds are most reduced (ca 6 windbreak heights downwind). Beyond 12 windbreak heights, however, temperatures close to the ground are effectively the same as those upwind. By comparison, wind speeds are still reduced by 30 - 60% at 12 windbreak heights and even at 25 windbreak heights, winds are still 10 – 15% lower than upwind. The vertical fluxes of heat and water are reduced in the quiet zone, but increase dramatically when the turbulent wake layer, generated at the top of the windbreak, intersects with the ground – at about 6 – 10 windbreak heights downwind. The spatial pattern of evaporation is thus quite different to the spatial pattern of wind protection.  A simple model is used to predict the downwind and vertical extent of the main airflow regimes, for flow normal to the windbreak. A wind speed reduction curve can then be modelled from the upwind terrain, plant cover and windbreak height and porosity. This curve can also be used to estimate the increase in air temperature. The effect of oblique winds on the amount of wind protection can be quantified for the model windbreaks used in our wind tunnel experiments. However, the structure of tree windbreaks - such as width and gaps in the trunk zone, mean that these predictions are less reliable within about 3 heights of a tree windbreak.
Implications	Windbreak effects on the microclimate are subtle. Temperature and humidity are slightly increased over relatively short distances downwind of the windbreak. These elevated temperatures in the quiet zone can enhance plant growth – both growth rates and biomass production. However, because wind speeds are reduced over much greater distances, a direct plant growth response to wind protection, e.g. from reduced damage due to sandblasting and leaf damage, may be a more important windbreak effect on plant growth and yields. As a result of reduced soil evaporation, the quiet zone may also be region of greater available soil water, at least early in the season and providing that competition with the tree windbreak is managed. Beyond the quiet zone, however, the pattern of evaporation does not match that for wind speed. Combined with the varying sensitivity of soil and plant evaporation to wind, and the highly variable wind climate in much of SE Australia, this means that soil water conservation is unlikely to be an important windbreak mechanism for plant growth.

 
 

Project Title	The impact of trees on the physical environment and productivity of farmlands
RIRDC Project No.:	DAW-49A
Researcher:	Rob Sudmeyer
Organisation:	Agriculture Western Australia RMB 50,  ESPERANCE WA 6450
Phone:	08 9083 1111
Fax:	08 9083 1100
Objectives	To quantify changes in microclimate and soil water content in the lee of windbreaks in Western Australia and relate these changes to subsequent crop growth and yield and groundwater recharge.
Background:	Windbreaks have been widely planted to increase crop and stock productivity and reduce the risk of wind erosion. In Australia there is also interest in using windbreaks as a means of introducing trees into conventional farming systems where trees can have income diversification and salinity amelioration benefits. Australian reports indicate that there can be considerable gains in crop and pasture growth in shelter. However, the paucity of published Australian information has been identified as a constraint to the adoption of farming systems incorporating windbreaks in Australia. Accordingly, crop growth behind windbreaks in Western Australia need to be evaluated in the light of local conditions and for each particular crop species. This project was part of the National Windbreak Program.
Research	There were four major components to the research. Firstly, the effect of high levels of shelter (artificial shelter) on microclimate and crop growth was evaluated. Secondly, the effects of tree windbreaks on microclimate, soil water content, soil flux and crop growth was quantified. Thirdly, crop yields in the lee of a number of windbreaks located across the Western Australian wheatbelt were assessed. Finally, the effectiveness of pruning roots as a method of minimising crop yield losses alongside windbreaks was evaluated.
Outcomes	Reducing windrun by 70% (inside artificial shelters) throughout the growing season had significant effects on crop growth but no effect on rates of plant development. In years with average or below average rainfall, biomass growth was significantly increased without increasing soil water use. For a determinate crop, such as wheat, this translated into a 20% increase in grain yield. For lupins, which are indeterminate, there was no increase in yield. In a year where the crop was waterlogged, decreased evaporative demand in the shelters caused a decrease in biomass growth and grain yield. In a natural tree windbreak systems, total growing season windrun was reduced by more than 20% with 6 H, but by less than 10% at 12 H. Potential evaporation was reduced by less than 10% at distances greater than 6H. There were significant reductions in soil flux within the windbreak system. Temperature changes were too small to affect rates of crop development, except where trees shaded the crop and temperatures were reduced. Crop growth and yield was significantly reduced within 3 H from the windbreak. More than 3 H from the windbreak, crop growth and yield was unchanged from open conditions except in an exceptionally dry year when yield was increased within 10 H. The only changes in soil water content which can be attributed to the windbreaks were found within 3 H. Within 3 H, the trees reduced soil water content, the depth and duration of perched water tables and the amount of groundwater recharge. Where lateral tree roots were confined within 1 m of the soil surface, pruning the roots significantly improved crop yields within 3 H. Where the roots were not confined , pruning had no effect on crop yield. A survey of windbreak sheltered crops showed that windbreaks do not improve yield between 3 and 20 H in years with average rainfall, slightly improved yields in years with below average rainfall and significantly improved yields at sites which suffer from wind erosion and sandblasting. In all years and sites, crops yield was reduced within 3 H of the trees. Only at sites suffering sandblasting did yield improvements offset losses near the trees.
Implications	While microclimate changes in shelter can have a considerable impact on the growth and yield of crops, the magnitude of microclimate changes in the lee of windbreaks is generally too small to have a significant impact on crop yield. The principle benefit of providing shelters is the reduction in physical damage to crops during severe wind events. Yield reductions alongside windbreaks should be minimised by severing the tree roots using a deep ripper.

 

Project Title	The effect of windbreaks on crop growth on the Atherton Tablelands in North Queensland.
RIRDC Project No.:	DAQ-147A
Researcher:	Amanda Snell, Simon Brooks.
Organisation:	Queensland Forest Research Institute DPI Forestry 83 Main St ATHERTON, QLD 4883
Phone:	07 40915200.
Fax:	07 40915211.
Email:	snella@dpi.qld.gov.au, brookssj@dpi.qld.gov.au
Objectives	To quantify the effects of windbreaks on crops such as maize, potatoes and peanuts.
Background:	Research was conducted on a privately owned farm just north of Atherton, on a flat site on deep red soil, The site has several three and four row windbreaks that were established in 1991. This project was part of the National Windbreak Program.
Research	Intensive measurements of crop morphology, growth and yield were conducted annually from 1994 to 1998 at increasing distances from the windbreak. Soil and climatic parameters were also regularly recorded. Data from these measures have been used to calculate changes in crop yields as distance from the windbreak increases, and to assist in explaining these changes. This data has also been utilised in the crop growth and windbreak models by APSRU.  Tree growth and windbreak composition has also been investigated.
Outcomes	Results over four potato crops have shown on increased yield in windbreak sheltered plants, and this may be due to a reduction in leaf damage from reduced wind flow. The total yield increase was between 6 and 9% out to 40 times the height of the windbreak. In 1998 a peanut crop showed a similar total increase of 12% in the yield of sheltered plants, and reductions in water stress closer to the windbreak. A three row windbreak of Melaleuca spp (low row), Eucalyptus spp (middle row) and Eucalyptus microcorys and Pinus caribaea var hondurensis (tall row) can result in a windbreak with a maximum height of 11m at age 7, that reduces wind flow to a maximum of between 44 and 54%. Positive influences of an 11m high windbreak extend up to 350 metres into a paddock and, for example, in 1997 resulted in an additional 11.4 tonnes of potatoes in one paddock. Four years of maize crop data suggests that there is no significant change in yield between sheltered and unsheltered treatments. However, significant decreases in maize leaf damage have also been measured for sheltered plants.
Implications	The results from the project suggest that the presence of relatively young windbreaks can positively affect the yield of horticultural crops such as potatoes and peanuts through a reduction in wind-speed and a decrease abrasive damage to plants. This result will have application to orchard crops such as mangoes, avocados, macadamia nuts, lychees and bananas that are grown on the tablelands.

 

Project Title	Effect of windbreaks on crop productivity in South Australia
RIRDC Project No.:	UA-25A
Researcher:	Ian K. Nuberg, Stephen J. Mylius
Organisation:	University of Adelaide Department of Agronomy and Farming Systems Roseworthy Campus, ROSEWORTHY SA
Phone:	08 8303 7729
Fax:	08 8303 7979
Objectives	To evaluate the value of windbreaks in South Australian cropping systems by determining their impact on water relations, biomass production and yields.
Background:	The shelter provided by windbreaks has been reported to enhance crop productivity by several mechanisms: directly through growth processes modified by microclimate changes, and physical protection of the crop from abrasion and lodging, and indirectly through its effect on soil conservation and soil moisture accession. Most of the windbreak literature reports the effect of shelter under very different conditions of climate and management than found in Australia. There was a need to evaluate the magnitude and mechanism of crop response to shelter under various farming systems in Australia. This project, which focussed on the investigation of the effect of shelter on crop water use, was the South Australian component of the National Windbreak Program.
Research	This project completed four years of field measurements of mainly wheat, but also canola, faba beans and oats under shelter created by an Aleppo pine windbreak as well as that created by an artificial windbreak and full enclosures. Detailed growth, yield and soil moisture measurements were made as well as a comprehensive soil characterisation of the natural windbreak site. During this period the crops were exposed to four very different seasons, from drought to well-watered. Wheat was also grown in sealed-system lysimeters under sheltered and exposed conditions to determine the effect of shelter on the efficiency with which water is used to produce plant biomass.
Outcomes	Elements of the classic windbreak signature could be detected in the yield responses of 6 out of 8 crop years and this was more pronounced in dry years. The yield differences of wheat across the paddock were well correlated with cumulative water use of the crop. However, these results are not unequivocal as covariate analysis of wheat and bean yield data with soil texture indicated that yield variation across the paddock could be explained by variation in depth to calcareous clay loam. Nevertheless, the windbreak did alter the microclimate such that wheat (but not canola) flowered earlier in the sheltered zone. It was also clearly shown that sheltered conditions will enhance the biomass production of wheat While there was no difference in total water use under sheltered and unsheltered conditions, that water was used to benefit vegetative growth but not grain filling. It was concluded that although shelter does affect the physiology of crops grown in this environment the effect on final yield is relatively subtle compared with other sources of yield variation. However, shelter does enhance biomass production of wheat most likely through its effect on the efficiency with which the crop uses water.
Implications	The shelter created by windbreaks in South Australian farming systems has a measurable effect on physiology and water use of wheat. While this may not result in greater grain yields the enhanced biomass production will be of value to farmers involved in fodder production (eg cereal hay and most likely lucerne). The results also imply that shelter may have a stronger effect on the yields of non-cereal crops and so further research on pulse and oilseed crops is warranted. The general value of windbreaks in this environment will be through their effect on protecting both crop and soil from the physical damage of strong winds.

Optimised Direct Returns from Tree Products
 

Project Title	National farm tree improvement program workshop
RIRDC Project No.:	SAR-17A
Researcher:	Peter Bulman
Organisation:	Primary Industries & Resources SA Box 752 MURRAY BRIDGE SA 5253
Phone:	08 8539 2117
Fax:	08 8523 5646
Email:	bulman.peter@saugov.sa.gov.au
Objectives	To improve national co-ordination of low rainfall farm forestry provenance trials, initially by holding a workshop of key players to evaluate the merit of: Choosing benchmark provenances so that comparisons can be made between regions & sites Sharing genetic material and adopting common methodology (trial design) Optimising the resources available to source and breed superior material
Background:	Efforts to identify superior* genetic material for low-rainfall farm forestry species have historically been limited and disparate. This deficiency has been well recognised at a range of fora (Yanchep workshop 1994, National Agroforestry Working Group (RWG 11) 1996 and AACM workshop last week in Adelaide). Such qualities include: good health and vigour eg tolerance to difficult sites, high water use for salinity and productivity for wood and plant products extra height to optimise shelter benefits good form eg straight trunks for timber or erect growth habit for broombush.
Research	The workshop was held in the Adelaide Hills, 3-5th November 1998 and incorporated paper presentations, workshop sessions and informal discussion.
Outcomes	improved knowledge of the current state of low rainfall tree selection and improvement research; and identification of research and information gaps—presented in the workshop proceedings a resolution to develop a collaborative national project proposal to locate, equitably share and develop superior genetic material for key species for hardwoods (Eucalyptus cladocalyx, E.maculata, E. occidentalis and E camaldulensis), softwoods (Pinus pinaster, P. radiata, P. brutia/halepensis) and short-rotation biomass crops (mallee oil species), incorporating standard protocols for designing, measuring and reporting on provenance trials and seed orchards  formation of a geographically-based, five-member Australian Low Rainfall Tree Improvement Group (ALRTIG) to guide the direction of collaborative work in the three key ‘modules’
Implications	Since the workshop such a national collaborative project has been developed (led by CSIRO), paving the way for more concerted and cost-effective development of low rainfall farm forestry in dry temperate and Mediterranean climatic zones of Australia.

 

Project Title	High value trees on farms
RIRDC Project No.:	UNE-34A
Researcher:	Alison Specht
Organisation:	School of Resource Science and Management Southern Cross University,  P.O. Box 157,  LISMORE N.S.W. 2480
Phone:	02 6620 3755
Fax:	02 6621 2669
Objectives	The objectives of this project were to: identify high value cabinet timber species appropriate for use on farms;  identify key site conditions commensurate with optimal growth; identify key management practices that improve growth; and test the value and manner of obtaining information from non-traditional plantings.
Background:	The use of high-value trees is an attractive component of diverse farming enterprises in the subtropics. Such trees can potentially provide a good medium to long-term alternative income source, with proportionally low maintenance in comparison with other farm activities. The selection of species, their management and monitoring, is, however, problematic, as little information is currently available. Most landholders are sceptical about the economic viability of the use of high-value trees on their properties and their ability to manage them. As a primary step in encouraging the adoption of such a new innovation, good information on possible species, their growth rates, site requirements and management, needs to be made available.
Research	There were four major components to the research: existing plantations of cabinet timber species were selected and site and management characteristics recorded using a systematic data recording system devised for the project; the growth of the species in each plantation was measured, with special attention to two experimental plantations established under National Afforestation Program funding, and various chemical and physical attributes assessed; the growth of fourteen species common to at least two plantations was compared with the various physical attributes of the sites on which the plantations were located.  the results were collated, the various species grouped into growth potential classes, qualities of suitable sites for each species explored, and management recommendations made where observations were sufficiently reliable.
Outcomes	It was demonstrated that it was possible to gain useful information from non-experimental plantations. There was a significant difference in the performance of the species planted at the various sites. The species were grouped into three classes according to growth rate to four years of age: high, medium and low. The highest growth rates were very favourable, with height increments of greater than one metre per annum. Moisture conditions proved to be the most indicative of both species suitability and performance. Several species clearly showed a preference for an ample supply of rain (? 160mm per month), while the growth of others was reduced at high rainfall, preferring a median amount of rain (circa 140mm per month). A high soil-water-holding capacity was important for a few species. Management factors were not as strongly related to performance as climate and soil factors, mainly due to the large variation in climate and soils between the sites and the lack of rigorous comparisons of treatments. All species showed a physiological behaviour consistent with a preference for organic soils, and a preference for a median (circa 15) to high (circa 22) C/N ratio was observed in several species. The benefits of mixed species and of variations in planting design were few. A couple of factors did emerge that are worthy of note, including the dominating effect of Acacia melanoxylon in mixed species plantings, the apparent benefit to Toona ciliata of having close neighbours, and the necessity for care in design of small mixed species plantings to avoid loss of early emergents.
Implications	With further work on aspects of soil fertility, management and design, and the effective dissemination of information and knowledge, high value cabinet species on farms will be an increasingly attractive proposition for the landholder in the subtropical east coast of Australia.

Cost Effective Multi-Purpose Agroforestry Systems
 

Project Title	Native forests on farms productive farm forestry through sustainable management of trees on farms
RIRDC Project No.:	AAC-2A
Researcher:	Mark Parsons
Organisation:	FORTECH 7-11 Barry Drive TURNER ACT 2612
Phone:	02 6248 6900
Fax:	02 6248 6999
Objectives	To provide a basis for developing a strategy for the sustainable management of native forests on farms.
Background:	Native forests on farms are an important component of Australia’s native forest sector. They account for around one quarter of the area of productive native forest in Australia. Despite the significance of private native forest resources in Australia, there is a limited farm forestry culture among landholders. There is an increasing focus on private sector resources throughout Australia which reflects increasing pressure on publicly owned forest resources, recognition of the need for sustainable forest management on both public and private land, and an increasing recognition of the commercial opportunities of forest management as part of agricultural businesses. RIRDC has initiated a project to develop a strategy to encourage and enable landowners to manage their forests to produce commercial products that provide a viable source of farm revenue while also sustaining non-commercial forest values.
Research	This project canvassed information available on the extent and types of private native forests in Australia, the economic contribution of these forests in each of the States, and the requirements for sustainable management of these forests, including sustainable yield calculations, market access, the legislative and regulatory framework for commercial forestry on private land, and the social and cultural factors that impact also. The development and progress of management processes are addressed, including farm forestry programs and the Regional Forest Agreement (RFA) process, which aims to establish the basis for long term sustainable forest development across all land tenures, and has led to an increased focus on private forest resources in Australia. Following this investigation and analysis, impediments to the further development of commercial farm forestry were identified.
Outcomes	The analysis of private native forest resources is severely limited by a lack of basic information on the extent and nature of these forest resources. In strategies designed to develop the sustainable management of native forests on farms, key issues to be addressed include: the need for strategic direction and support at a national level; removal of legal and regulatory impediments to the sustainable management of private native forests; the need for reliable and accessible regional information on the status and potential of private native forests; the need for increased landholder skills with respect to silviculture, forest management and marketing forest products; the need to assist landholders evaluate the potential for managing native forest resources within the economic context of whole farm planning; and the lack of sufficient markets for the full range of non-sawlog products.
Implications	Encouraging and facilitating the sustainable management of native forests on farms by the above actions may hasten the development of a farm forestry culture in Australia.

Project Title	An assessment of commercial prospects for planted tree species in the low rainfall zones of Australia
RIRDC Project No.:	AGT-4A
Researcher:	Peter Chudleigh
Organisation:	Agtrans Research ,  PO Box 385,  TOOWONG QLD 4066
Phone:	07 3870 9564
Fax:	07 3371 3381
Objectives	To assess the commercial opportunities for growing a range of tree species in the medium to low rainfall areas of Australia, and  To establish priorities by commercial product and species type to assist resource allocation in R&D funding by the Joint Venture Agroforestry Committee.
Background:	Sustainability benefits are being sought from widespread plantings of trees in many agroecological zones of Australia. In particular the impacts of dryland salinity may be alleviated by tree planting. Many of these impacts are most severe in the medium to low rainfall areas of eastern, southern and western Australia. The identification of land use activities that may provide commercial returns would be extremely valuable to the attainment of an increase in planted areas that may in turn provide additional sustainability benefits. Relevant information on the prospective markets and economics for various tree species and product forms suitable to this zone was important to assist the Committee with further R&D planning.
Research	The study has followed a framework of defining various product forms, the market for such products and the economics of actually establishing trees to target the particular markets. Further dimensions addressed are those of a species list and assessment criteria. Information sources included various researchers, Landcare Groups, Government Departments commercial and industrial organisations, written literature and the internet. Information on the sustainability impacts has not been given much attention in line with the prime objective of the project to assess commercial profitability. However, any assessment of the overall economics of producitng different product forms can only be indicative unless the sustainability benefits and costs are considered.
Outcomes	Economic analyses were carried out for four agroforestry enterprises: sawntimber, firewood, biomass for electricity and eucalyptus oil production. Of the four enterprises analysed, the most commercially viable operation for low rainfall agroforestry was eucalyptus oil production. The most promising commercial opportunities identified for the low rainfall (400-600mm rainfall) zone include the following. Planting for fodder species, production of eucalyptus oil, and electricity produced from by-products and residues. Two important concepts in considering commercial prospects are that of flexible production systems and multiple products. Also, a number of uncertainties exist for low rainfall zone agroforestry which could affect the economic viability of agroforestry enterprises in general. These include the threat of species dying after a series of poor seasons. Also, limited knowledge is known about how many of these species might adapt to a plantation situation. Design could also be very important in the capturing of sustainability benefits that might be targeted from low rainfall agroforestry. When included in economic assessments of the agroforestry enterprises, sustainability impacts can have a significant impact on the economic viability from the viewpoint of the private landholder, as well as society. As well as sustainability benefits, carbon credits, if they eventuate, could provide additional income required to make the 'almost commercial' enterprises economically viable.
Implications	Commercial agroforestry in the low rainfall region of Australia is unlikely to be as profitable as in the high rainfall zone due to lower growth rates, less established infrastructure and greater distance to markets. However, this study has demonstrated that significant prospects exist and benefits should be capturable with further private and public R&D investment and encouragement of innovation and infrastructure support by government.

 
 

Project Title	Ultra-short duration agroforestry rotations for low rainfall areas (Phase Farming with Trees)
RIRDC Project No.:	CAL 3A
Researcher:	Dr Richard J. Harper
Organisation:	WA Department of Conservation and Land Management; CSIRO Land and Water,  University of WA (Soil Science)
Phone:	08 9334 0306
Fax:	08 9334 0327
Email:	richardh@calm.wa.gov.au
Objectives	Determine whether phase farming with trees in low (<400 mm) rainfall areas can rapidly de-water farming catchments at risk from salinity by depleting unsaturated stored soil water and reducing recharge while producing utilizable products.
Background:	Trees are recognised as an effective means of containing salinity, which threatens over 11.8 Mha of productive land in Australia. Uncertainties about appropriate species, their placement and long lags until commercial return may inhibit farm tree planting. A method, which offers certainty of de-watering target areas and producing a commercial product in a very short period, may enhance tree planting.  Phase Farming with Trees (PFT) is designed to use trees grown in very short rotations (3-5 years) to rapidly de-water farming catchments, at risk of salinity by depleting unsaturated soil water storage and reducing recharge. Trees would form temporary elements in rotations with annual crops; this increasing the sustainability of current farming systems, while allowing farming to continue.
Research	A $25,000 desk-top study was undertaken. This (a) reviewed existing ultra-short rotation agroforestry systems, (b) identified likely end-products of the system, (c) modelled the likely effects of the system on catchment water balances for typical environments in Western Australia and the Murray Darling Basin, (d) identified likely impacts on soil physical, chemical and biological properties and (e) undertook an overall economic analysis, bringing both products and the value of improved land and sustainable land-use to account.
Outcomes	The study suggests that the system is highly promising in specific environments in terms of both hydrological effectiveness and positive benefits on soil biological fertility. The economic analysis suggests that the system will be marginally economic, in its own right in areas with low rainfall (<400 mm). Reducing costs of establishment, identifying tree products with greater value and bringing land conservation benefits into account would improve PFT returns.
Implications	Potential benefits include decreased salinization, improved farm cash-flows, improved soil structure and reduced soil-borne disease. It is suggested that the project now be considered for full funding of a detailed trial and demonstration of the system’s potential.

 
 

Project Title	Growing Trees on Cotton Farms, a guide to assist cotton farmers decide how, when, where and why to plant trees
RIRDC Project No.:	QDN - 2A
Researcher:	Peter Voller
Organisation:	Dept of Natural Resources PO Box 589 DALBY Q 4405
Phone:	07 46699576
Fax:	07 46625310
Email:	peter.voller@dnr.qld.gov.au
Objectives	To provide cotton farmers with information on tree growing with particular relevance to their industry.
Background:	Cotton farms are characterised by heavy or clay soils, flat or moderately sloping landform, highly mechanised agronomy, including aerial spraying and innovative or progressive land managers. There are a number of opportunities for integration of trees into cotton farming systems and there has been an expressed interest from growers for more information on the subject.
Research	This project entailed the compilation of a report on existing knowledge of tree growing relevant to cotton growing areas. A range of specialist authors were involved in the production of a package which contains information on tree growing for a number of purposes, such as spray drift capture, windbreaks, wood production, salinity management, creek bank stability and nature conservation. The package also contains information on establishment and management techniques of relevance to cotton growing areas and a number of case studies of farms already planting trees.
Outcomes	3000 copies of the publication 'Growing Trees on Cotton Farms' have been produced, a copy is to be sent to each cotton grower in Australia. Further information is to be provided in a series of field days to be organised through late 1999 and early 2000.
Implications	The publication of this booklet should provide cotton farmers with an additional source of information on the subject of tree growing on their land. It is expected this will stimulate interest in farm forestry, spray drift capture and other functional uses fro tree planting.
This project was jointly funded with the CRDC

Effective Communications
 

Project Title	Decision support tools for adoption of agroforestry
RIRDC Project No.:	DAW-84A
Researcher:	Peter P Eckersley
Organisation:	Agriculture Western Australia  PO Box 1231  BUNBURY WA 6230
Phone:	+61 8 9780 6204
Fax:	+61 8 9780 6136
Email:	peckersley@agric.wa.gov.au
Objectives	To promote the adoption of agroforestry systems by providing farmers with decision aids to quantify the impact of agroforestry adoption on the farm business.
Background:	A limited number of commercial tree crops have shown great potential for improving farming systems in the high rainfall zone, slowing or reversing land degradation and meet the growing demand for wood fibre. However, adopting agroforestry is a big step to take for the manager of a small business that is used to a regular annual cashflow, and unsure of the performance of these trees. A particular challenge is to integrate the projected costs, prices and yields into a measure of profit to compare it with traditional farming. Most farmers and farm advisers have little experience of, or information about, best bet commercial tree crops. They do not have easy tools to perform discounted cashflow analysis, which is needed to compare long rotation crops with traditional enterprises. It was proposed to design a computer-based tool that would be simpler than the simulation models which can only be used by agency specialists.
Research	Campbell White & Associates Pty Limited was contracted by Agriculture WA to design a set of such tools. The consultants identified the need for such a tool (model) to be linear, so the user can easily work through it in one pass. It should require a minimum of key strokes. The user should be able to select one of a set of best bet agroforestry enterprises, customise the budget to fit their own farm, and observe the expected profitability relative to normal land use. Several versions of a model were tested by a network of agroforestry practitioners in three southern States.
Outcomes	Campbell White & Associates have developed AGROFORESTRY CALCULATOR. This is a user-friendly spreadsheet-based tool for farmers and their advisers to estimate the profitability of best-bet agroforestry projects. The user selects a predefined forestry enterprise that already has production, cost and management information associated with it. Within each region, information on each enterprise must first be entered by an experienced agroforestry professional. The model can hold a large number of enterprises. Options include comparison with an annuity and addition of a landcare benefit. It is proposed that AGROFORESTRY CALCULATOR and the user manual be made available on the Agro-economic Models Database at Agriculture Western Australia for down-loading over the internet.
Implications	Farm forestry specialists in all States now have the opportunity (and obligation) to supply detailed information on best bet tree crop options to farmers and advisers in a form in which they can assess profitability for themselves.

 

Last updated: 17 November 1999
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