We have just experienced one of the wettest winters on record in several parts of the UK, and so many of our sites remain saturated in places. This increases the risk of machinery becoming bogged.


  • Machinery getting bogged is, by its very nature, unplanned. Human nature often drives the temptation to try and recover the machine as quickly as possible to avoid delaying works, without fully assessing the environmental and safety hazards associated with the process of de-bogging machinery.

It’s important to consider the risk of machines becoming bogged at the planning stage and include it within a pre-commencement meeting, hazards and constraints map, and risk assessments. This must remain under review as the site progresses. Operator feedback on site conditions as work progresses is a vital tool to prevent machines becoming bogged.

Your assessment will need to include the following:

  • Plan travelling routes and avoid, or thatch, any wet or rutted If in doubt, use an alternative route if you can and be prepared to stop work if the site becomes too wet.
  • Mark known wet or soft ground areas on Hazard Map.
  • Make an assessment of the quantity and quality of the brash likely to be available to create extraction racks.
  • Assess the suitability of the proposed machinery for the site conditions.
  • Will low ground pressure vehicles be required?
  • What equipment you would need onsite if a machine became bogged.
  • What materials/equipment are needed to manage the risk of diffuse pollution.

If a machine becomes bogged, the operator should:

  • Stop all drive to tracks and/or wheels.
  • Make the machine safe.
  • Dismount the machine safely (e.g. climb off it on the high side when on a slope, if practicable).
  • Assess the situation.
  • Advise the Forest Works Manager and arrange for any assistance that is required.
  • Consider anything that may help with recovery (e.g. partial or full unloading).
  • Consider emergency drainage, if safe to do so, where the engine or its components may be damaged by ponded water.

Once a machine has become bogged, before recovery is started the situation must be assessed:

  • Do you have sufficient and suitable recovery equipment on site?
  • All operators must have received training in how to operate the equipment and to do the tasks required.
  • What safety and environmental risks remain and how will this be controlled?
  • Do you need external professional specialist recovery?
  • For more assistance in planning safe recovery operations refer to FISA Safety Guide 703


  • STOP – stop and assess the Do not try to remove bogged machinery without first considering the risks.
  • THINK – think and discuss a plan with others on site.
  • PLAN – plans should be made at pre-commencement and areas of bogging risk identified before the work This must be reviewed as the work progresses. If a machine does become bogged you must carefully plan its removal.
  • Ensure that all personnel are in a safe place including those who are stood watching.