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Environment Protection Authority

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Native forestry

Trial of timber harvesting on steep slopes

Proposed trial of timber harvesting on steep slopes

On 24 February 2014, the NSW Government released a discussion paper (PDF, 2MB) outlining the key elements of the proposed integrated forestry operations approval (IFOA) remake. The discussion paper included information about a proposal for a small-scale steep-slope harvesting trial. The proposed trial is at a conceptual stage and no pre-trial planning or on-ground works have started.

The information provided in the discussion paper does not represent the scope of the trial and provides indicative background information only.

A decision on whether the trial will go ahead will be made as part of the IFOA remake.

If it does proceed, the trial will be subject to approval by the EPA and will be required to meet strict conditions to ensure that environmental impacts are minimised while the assessment is undertaken.

Harvesting on steep slopes will only be considered more broadly if the trial demonstrates that the environmental impacts are negligible.

Harvesting on steep slopes is currently restricted under the coastal IFOAs because conventional ground-based harvesting and extraction in these areas would significantly increase the potential for soil erosion and water pollution.

To overcome these limitations, other forestry jurisdictions in Australia and overseas have adopted alternative methods such as cable extraction to access and extract timber. This technique not only allows access to the resource, but also improves soil and water outcomes by significantly reducing soil disturbance and the risk of soil erosion and water pollution.

If the trial proceeds, the Forestry Corporation of NSW (FCNSW) would oversee the study to determine which techniques could best be used to augment ground-based methods on steep country in coastal NSW. This would include evaluating the benefits, costs, operational constraints and controls that might be necessary to access timber in areas with predominantly steep slopes, while still meeting the environmental objectives of the IFOA.

FCNSW planning staff assess forests on steep slopes in the Urunga Management Area (FCNSW)

FCNSW planning staff assess forests on steep slopes in the Urunga Management Area (FCNSW)

Where the trial can take place

The map shows areas of forest that have substantial areas of steep slopes suitable for running a trial. These state forests are located on the mid-north coast of NSW to the west of Urunga and Nambucca Heads. The proposed trial could be carried out at one or more sample sites within this broad area.

Potential areas in north-east NSW where steep slopes predominate

Potential areas in north-east NSW where steep slopes predominate

The potential sites have previously been harvested and accessed using ground-based extraction methods. This spatial image, produced using LiDAR data, shows extraction tracks used in previous harvesting in the area between the 1950s and 1980s. These tracks were allowable under previous harvesting regimes, prior to the introduction of the IFOAs and a 30 degree extraction limit for ground-based extraction.

LiDAR-shaded relief image of Oakes State Forest, west of Urunga

LiDAR-shaded relief image of Oakes State Forest, west of Urunga

The area is typically covered in regrowth stands with a high proportion of blackbutt, the commercial species in highest demand on the north coast of NSW.

Blackbutt regrowth forest in Oakes State Forest on slopes with grades frequently exceeding 30 degrees (FCNSW)

Blackbutt regrowth forest in Oakes State Forest on slopes with grades frequently exceeding 30 degrees (FCNSW)

Trial planning and design

A desktop planning exercise would be used to determine the most appropriate machinery to be used in the trial. Specialised cable-harvesting modelling software would be used to determine the potential logistics of the trial under various technology (machinery) configurations including:

  • the weight of logs extracted by machinery configuration
  • the height of suspension of load above groundline
  • access to the harvest area
  • infrastructure requirements
  • any potential conflicts with the regulatory settings of the IFOA.

The cable harvesting software package would enable the creation of a detailed logistics plan for a trial. Using the software, topographic information can be extracted from GIS (contours, slopes, rise and run) and analysed to determine extraction paths for logs suspended by a fixed cable.

Example spatial layout for a selective cable harvesting operation in Compartments 149, 151 and 152. This example was based on an excavator yarder, working in combination with a skidder or forwarder. Map shows LiDAR-derived slopes, watercourses and infrastructure, while boundaries and harvest exclusion areas are derived from standard GIS map layers used FCNSW.

Example spatial layout

Trial implementation, monitoring and evaluation

FCNSW anticipates that once a trial design has been finalised, a contractor would be engaged to undertake the work. The trial would be planned in accordance with the best-practice planning requirements specified in the new IFOA and would also include any specific amendments required to facilitate the use of the chosen technology.

The EPA and DPI would be consulted in the development of a trial harvest plan. The final plan would then be lodged with the EPA and the DPI and made publically available.

The trial would be closely monitored by FCNSW staff to ensure it is carried out to the required specifications and the specified environmental outcomes are met. The EPA and DPI would monitor FCNSW compliance with the IFOA throughout implementation of the trial.

Evaluation criteria will be developed in consultation with the EPA and DPI prior to the trial. A report on the trial evaluation would be used to determine its efficacy and the potential future operational implementation of harvesting in country with predominantly steep slopes. The EPA and DPI would consider the results of monitoring provided by FCNSW.

The EPA, DPI and FCNSW would jointly negotiate any IFOA amendments required following a trial and the decision to expand logging on steep slopes.

Page last updated: 17 February 2015