Upper Great Southern Oil Mallee Growers Association
Project Profile
| Name of Project | Integrated Mallee Tree Planting Canopy and Root Management Demonstration Project |
| Name of group(s) involved | Upper Great Southern Oil Mallee Growers Association |
| Time frame | 2009-2011 |
| Website | www.oilmallee.org.au |
| Location | Narrogin |
| State | Western Australia |
| NRM Region | South West Catchments Council and Wheatbelt NRM |
| What industry does the group belong to? | Broad-acre cropping – Oil Mallee |
| Corporate Partners involved | Woolworths |
| Level of Funding from LAL | $22,000 |
| Funding from other sources | $1,800 |
Issues
Revegetation with woody perennials in Western Australia has been an essential component in restoring ecosystem water, nutrient and energy balance.
Large scale plantings across the whole farming landscape using the hardy ‘Mallee’ eucalypt species has been expanding since the 1990’s in Western Australia.
Often planted in ‘alley belts’, these trees have performed well, however, the management of emerging and undesirable ‘competition aspects’ of tree growth, commonly referred to as the ‘competition zone’, has been impacting on the adjacent crop and pasture systems.
The Upper Great Southern Oil Mallee Growers Association with support from a Woolworths Sustainable Farming Grant has visually demonstrated that non destructive cutting and coppice management of mallee trees enhanced coexistence between the two land use systems of tree farms and adjacent crops and pastures.
The project selected a number of existing, advanced mallee plantings integrated across farm land and these were strategically cut prior to crop and pasture establishment. Root competition severance and ‘re-colonisation’ of crop and pasture growth into the ‘competition zone’ was monitored.
The project selected a number of existing, advanced mallee plantings integrated across farm land and these were strategically cut prior to crop and pasture establishment. Root competition severance and ‘re-colonisation’ of crop and pasture growth into the ‘competition zone’ was monitored.
Extensive use of photo records visually demonstrated the positive impact of the cutting action in reducing tree competition and increasing density of adjacent crops and pasture in the competition zone.
Project Detail
| Background to Project | Since the early 1990’s Western Australian farmers have been encouraged to adopt dispersed large scale woody perennial plantings across the whole farming landscape using the hardy ‘Mallee’ eucalypt species.Revegetation with woody perennials in Western Australia has been an essential component in restoring ecosystem water, nutrient and energy balance. Integrating woody perennials, such as the endemic mallee eucalypt species, has also provided many other environmental services such as habitat creation and linkage and wind and water erosion control while retarding landscape leakage of nutrients and salts into adjacent land and water assets.
The oil mallee industry is more recently emerging as a potential addition to dryland agricultural systems with many attributes that can also improve farming practice. Visit the Oil Mallee Industry Development Plan for more information.
http://www.oilmallee.org.au/index.php/site/industry-development The strategic selection and deployment of species suitable to non destructive, short rotation harvests also facilitates regionally new industry stimulation and downstream processing of the embodied energy and products that are captured in the living solar cell process of photosynthesis.
The mallee plantings have afforded farmers multiple environmental and potential socio-economic outcomes such as wind /salinity control, new farm enterprise opportunities and climate readiness.
It has also been seen as an important component of developing innovative robust and carbon neutral future farm systems. The Upper Great Southern Oil Mallee Growers Network has over 150 landholder members and is based in the Wheatbelt Region of Western Australia’s Upper Great Southern Agricultural Zone. The group has been operating since 1996 and advocates the need for integrated tree plantings for sustainable farm practice, environmental services and prospective new industry development for community development. The Network has overseen the establishment of over 5000 hectares (or 10 million mallee tree plantings) in the region. The group provides extension support to landholders and is an active promoter of future farm systems using integrated woody perennials. They advocate the strategic re-establishment of tree plantings within a farm system context and members are leading by example.
Often planted in ‘alley belts’, mallee trees planted in Western Australia have performed well to date although the management of the emergent and undesirable ‘competition aspects’ of tree growth impacting on the adjacent crop and pasture systems, commonly referred to as the ‘competition zone’, has been an issue. This is particularly significant where there are shallow duplex over clay soils.
Potential production penalties emanating from tree canopies ‘branching off’ and, 1) contaminating adjacent crops and/or, 2) tree roots ‘robbing’ crop/ pasture nutrients and moisture, has been recognised as a major barrier for farmers furthering the cause for continued whole of landscape integration of tree planting within broadacre farm systems.
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| Key Objectives | The aim of the project was to explore and promote management options demonstrating to farmers a practical means of managing integrated tree planting ‘competition’ aspects of mallee trees [root and canopy extension] by undertaking non destructive cutting methods of the ‘competition’ trees. This would in turn build landholder capacity and encourage greater adoption of distributed plantings. |
| Description of Project | Project logic, site selection and landholder support was initially established.The project identified three advanced mallee tree planting locations and six site plots (with participating farmers) where trees were posing high competition demands on adjacent crops and pastures resulting in physical yield reduction.
Various tree harvest and handling options were explored within the project scope to further develop a body of knowledge and understanding towards the most practical and economic means of undertaking the cutting and handling task.
Canopy cutting machinery was explored to efficiently and effectively ‘groom back’ the stems to mallee lignotuber height thus triggering the natural response of the mallee tree to ‘coppice’ new growth. Two cutting contractors using different types of machinery – a clean saw ‘Fella Buncher’ and mulch heads – enabled the comparison of machinery capacity. Cutting was staggered across the sites to demonstrate the impact of this intervention. The plantings were strategically cut prior to crop and pasture establishment on the adjacent land.
The project was designed to be highly visual in its outputs. Photo point sites were established to visually photograph before and after, recording and monitoring the impact of the cut area and adjacent land use response over a period of twelve months.
A demonstration field walk was conducted to review the impact of cutting on mallees and a community field walk and presentation day was held to display the results.
The Oil Mallee Association of Australia, Wagin Woodanilling Landcare Zone and Avongro all provided support to the project.
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| Issues encountered during the project | • The demonstration field walk had to move to a DEC biomass cutting and measurement trial site on the demonstration day as a fire ban prohibited paddock access to Woolworth project cutting sites • Accurate yield measurements were not able to be undertaken due to dry seasonal conditions and poor overall growth of the adjacent crop and pasture |
| Project Outcomes – Qualitative | • Insights into adaptability of machinery usage for mallee tree management • The highly visual nature of the project and photo documentation of the positive ‘non destructive’ impact of cutting mallee trees has enabled the group to add to a larger body of landholder knowledge and capacity to integrate the tree crop and understand future management needs • It is now being promoted as a component of Best Management Practice for oil mallee growing and informs the Oil Mallee Industry Development Plan • Potentially, all mallee growers could adopt these management techniques, particularly those with shallow duplex over clay soil types |
| Project Outcomes – Quantitative | • Extensive use of photo records visually demonstrated there was evidence suggesting a positive impact of cutting action that reduced tree competition and increased adjacent crops and pasture density. (The action of cutting the canopy and triggering a coppice cycle leading to a ‘draw back’ of each of the tree root resources resulted in root retarding which permitted crop and pastures to re-establish adjacent to the tree belts). It must be noted that the performance of crop and pasture was greatly affected by a dry growing season in 2010 though visual evidence was still apparent. |
| Lessons Learned | • Both types of machinery used demonstrated an impact but from an industry development point of view, the probability for adverse affects such as tree damage or more expensive handling options of material waste were reduced using the clean cut machinery • Extensive photo records demonstrated a visual impact of the benefits of cutting mallee trees providing an excellent resource to promote the adoption of these practices across the oil mallee industry |
| Transferable Outcomes | • The knowledge gained is highly transferable and will assist in reducing adopter reticence and other perceived management barriers to integrated mallee farm systems • A number of project promotions were undertaken to spread the word via member newsletter, group presentations and an agricultural field day• Promotion of the project was extended to a larger audience than expected via opportunistic invites to address farmer groups as part of other Regional NRM workshops on integrated oil mallee systems • The project activities and impact of cutting will be monitored over an extended time frame to determine a frequency of need assisting broader industry development needs when considering issues of future harvest planning and frequency
• Knowledge gained from the project now informs the Oil Mallee Industry Development Plan
• The findings from this project will assist in the ongoing development of innovative robust and carbon neutral future farm systems
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Photography
Example of integrated mallee planting typically found in the region. Established as a NRM and production component of sustainable future farm systems.
Example of undesirable ‘Competition zone’ in 15 year old mallee planting and adjacent production impact that needs management intervention to overcome adoption barrier.
Cutting using Forest Logging Fella Buncher, O’Hallorans, Kojonup, 26 April 2010
Cutting using Forest Logging Fella Buncher, O’Halloran’s, marker tags protect excluded sections, 26 April 2010
Cutting using Positrak mulcher, Parnell’s, Tincurrin, 8 March 2010, Site 3
Cutting using Positrak mulcher, Parnell’s, Tincurrin, Site 3
Evidence of pasture re-establishing adjacent to cut mallees, Parnell’s, Tincurrin, November 2010, Site 2
Evidence of pasture re-establishing adjacent to cut mallees, Parnell’s, Tincurrin, November 2010
Evidence of Crop performance increasing adjacent to cut mallee, Parnell’s, Tincurrin, 13 Sept 2010, Site 4
Evidence of Crop performance increasing adjacent to cut mallee, Parnell’s, Tincurrin, 13 Sept 2010, Site 4
DEC Cutting/ Biomass Yield Trial, McDougall’s, Tincurrin, 12 September 2010
Field Day at DEC Cutting/ Biomass Yield Trial, McDougall’s, Tincurrin, 4 November 2010, (Note - 1 month regrowth from cutting)
