Clean Strip

Lead researchers: Dr Jim O'Hehir, Dr Jack Desbiolles and Braden Jenkin

The Project

Evaluation (safety, sustainability, establishment system efficiency & growth) of mechanical treatment of evenly distributed harvest residues by sweeping into rows to create a residue clear tilled row for subsequent operations.

This project seeks to identify a best combination of investment of finite funds in site preparation by deconstructing silvicultural regimes for Radiata pine and Tasmanian bluegums in the Green Triangle and inserting a novel system combining harvest residue conservation by strategic placement and soil tillage. A best combination is to be defined by biological, OHS, management and financial outcomes.

Industry Partners

The University of South Australia will collaborate on this project with:

Australian Bluegum Plantations Pty Ltd, Forest Products Commission, Green Triangle Forest Products, HQPlantations Pty Ltd, Hancock Victorian Plantations, Midway Plantations Pty Ltd, OneFortyOne Plantations, SFM, Sylva Systems, Nuland Contracting and Forest and Wood Products Australia

Our Research Approach

A compartment level trial will implement routine (control) treatments (chopper rolling, ridging and use of a Bracke) and clean-row treatments in blocks. The control treatments will alternate with clean-row treatment options to provide a consistent control basis across sites. The control treatment will be defined based on what would have been the usual treatment for each site. This will allow capture of production rates, operator

thoughts and broad-scale implications. A series of perpendicular sub-treatments are to be applied across the blocks of residue management and tillage treatments. These will include complete weed control and manual removal of any missed harvest residues. Other options will be determined. Assessment will include the implications of inclusion of these systems on the other components of establishment (enhancing, cost savings etc), the tree growth outcomes (e.g. survival and height at 9 months) and whether the residue system enables other novel inputs to establishment (e.g. precision systems). Data will be captured by qualitative (e.g. interviews of planting contractors) and quantitative methods (e.g. survival and tree measurement). Analysis will be to determine impacts and implications.

Expected Outcomes

Given that most plantations are subsequent rotation sites, where ground-based machines can access and where processing has been at the stump, clean row establishment systems are applicable. It is possible that inclusion of these systems will have a positive impact on other elements of establishment (e.g. reducing costs and/or improving outcomes) while reducing risks (e.g. enhanced personnel safety and planting stock deaths).

Expected specific impacts are to be as follows.

• Reduced trip and jarring hazards for planting contractors.
• Maintaining and potentially improving site productivity by better management of nutrients and soil moisture.
• A more uniform plantation with enhanced survival and initial tree growth that better expresses the crops genetic potential.
• A reduction in time between harvest and re-establishment by negating a need to allow harvest residues to dry-out with a parallel reduction in time to harvest of the next crop.
• A better allocation of costs between the other elements of establishment, with a potential for overall savings in total establishment costs.
• Meetings of obligations under certification to sustainably manage sites and make less use of chemicals.

Potential Impacts

The project seeks to assess the impact of novel harvest residue management systems combined with soil tillage options. The objective is to evaluate operational costs (e.g. across the whole of establishment), site sustainability (e.g. management of harvest residues and soil moisture) and silvicultural benefits (e.g. tree survival, initial growth and weed competition) associated with tree planting on reduced residue and tilled beds adjacent to inter-rows with concentrated harvest residues.

Project Outputs

• An understanding of impact of deconstructing current site preparation and establishment of softwood and hardwood plantations and including a novel technology for harvest residue management combined with soil tillage treatments. This assessment will define the impact on other components of site preparation and establishment from a safety, financial and operational perspective.
• An initial understanding of the tree survival and growth, and weed impacts of a different approach to managing harvest residues and ridge tillage as part of site preparation and establishment. An understanding of the interactions with site attributes pertinent to tree establishment, survival and growth. Given the short duration of the project, the intent is to develop a project sunset mechanism to ensure ongoing management and monitoring of the trials to provide longer-term understanding of the impacts of these novel residue management and tillage systems.
• A desk-top analysis of a range of current and emerging technologies for use in plantation establishment and management. This trial will provide insights into alternative treatments and considerations relevant to each in regard to enabling deployment in clear-row environment.
• Establishing the alternative treatments across a larger site and inclusion of routine treatments allows this trial to be used beyond the project timeframe as a demonstration site for industry in the Green Triangle and nationally.