Basic rule: Operational safety through use of machinery

  1. Human health is the most important consideration. Safety is more important than costs and loss of timber.
  2. Don't attempt to bring down lodged trees without direct access to a machine.
  3. On site trees should only be cut at the stump. All further work can then be done on a conversion site, where the stems can be processed safely.
  4. For operational safety reasons, a sufficiently powerful crawler excavator with a clamshell is to be used to untangle trees on large windthrow areas. Clamping the tree also avoids splitting of the stem. Cable skidders are less appropriate. Grapple skidders should only be used on site if more suitable machinery is not available.
  5. Cable skidders, preferably with a grapple, can be used for minor volumes, more or less uniformly in the direction of windthrow and on slopes.
  6. On steep slopes, cable cranes are used to untangle trees. Stems can be trimmed and crosscut on the roadside.
  7. Operational safety is enhanced when the woodcutter and machine operator communicate via walkie-talkies. Forest workers have to wear clearly visible reflective clothing.
  8. With particularly dangerous trees, it is advisable to leave a safety lug, preferably in a desired length. This can be cut off and skidded later.
  9. Where roots are particularly dangerous, they can be secured by the cable skidder or the crawler excavator.
  10. Grapple skidders can be used to manipulate timber accurately and to remove brushwood.
Tips for the use of crawler excavators for untangling windthrown trees
  • Crawler excavators should have a capacity of at least 100 KW to ensure enough reserves, especially for grappling and lifting. Its not only the range but the combination of range and lifting power which is crucial. The weight of the excavator ought to be at least 25 tons. This increases operational safety and productivity. Basic principle: Rather an over-dimensioned machine than an under-dimensioned one.
  • Crawler excavators with a range below 10 metres are not appropriate. The higher the range the better (distance between skid roads!).
  • Distances between skid roads do not automatically equal twice the range of the machine. All procedural actions to maximise the distance should be taken. The skid roads have to be marked out before the operation begins. This enables the woodcutter to identify the crane range and can therefore influence accessibility of the tree through crosscutting. Basic principle: It’s better to keep different qualities together and crosscut them later on the conversion site.
  • Straight skid roads facilitate skidding.
  • Using a big, solid grapple (with rotator) is advantageous for handling remaining logs. Excavators with a griper for demolition works proved to be convenient.
  • Ordinary crawler excavators (without tiltable cab) may only be used on gradients less than 15% inclination, even in the fall line. Do not use on steep slopes!
  • The crawler excavator has to prepare the skid road in a way that the skidder can use it at any time. Logs have to be left on the skid road or removed.
  • Crawler excavators are often operated by employees of the building industry without any experience and training in the forestry sector. Therefore, an intensive instruction is necessary, especially in teamworking with the chainsaw operator.
  • The chainsaw operator has to keep a minimum safety distance from the excavator and must wear reflective clothing. The excavator is used to help the chainsaw operator by untangling logs. Walkie-talkies are necessary for communication.

Assignment of contractors

Experiences after Storm "Lothar"

In 2000, contractors worked on a large scale for all types of forests owners in salvage logging. Due to the limited extent of the damage in Baden-Wuerttemberg (and small parts in Bavaria) as well as pan-Europe in France and Switzerland, it was quickly apparent that there would be no lack of logging and skidding contractors. The more serious problem turned out to be the selection of trustworthy and top-quality forest contractors, who could maintain the established quality standards (e.g. careful logging and compliance of the accident prevention regulation). The cooperation of long-time business partners has in most cases proved the best solution due to familiarity with the sites and the requirements of the forest office.


  • External contractors
  • Communication problems with foreign workers
  • Insufficient technical equipment, under-dimensioned/old machines, resulting in driving across the entire area
  • Rare compliance with accident prevention regulations
  • Rare compliance with quality-standards/care-standards
  • Frequent untrustworthiness

Organising Work

  • State forester's area to control was too large, "overworked and no time to maintain quality-standards"
  • Disregarding of quality standards in general, especially in favor of quick logging

Before contract completion:

  • The engagement of known contractors is best. There is often a long-standing, trusted cooperative relationship. The reduced need for control and instruction should not be underestimated in times of coping with storm damages.
  • The contractor market is large. Even in the event of enormous storm occurrences it’s not necessary to accept the first tender (especially if an unknown and/or external contractor). There is enough time to select by attributes.
  • The cheapest contractor is not necessary the best contractor. The offers need to be assessed in terms of additional costs (e.g. need of later clearing and slash disposal as a result of different working techniques or more time and effort for supervision of external contractors)
  • References of unknown contractors need to be provided and (if possible) checked.
  • With unknown contractors, contracts should be made on a quantity basis (up to 5000 m³). Further contracts should be entered into if the operation meets expectation. This isn’t always easy to achieve, but experience has shown that it is worthwhile to choose the “right” contractor to relieve the forest ranger’s work.
  • Before contract signing, a detailed instruction of working techniques and quality-standards is necessary. Especially important is the definition of settlement and method of log measurement. In particular the prohibition of driving areas and compliance with skid roads must be pointed out. The contractor must commit him/herself to using the machinery named in the offer or similar.
  • Before contract commencement the general terms and conditions and requirements regarding forestry work as well as differing forest district specific requirements need to be talked through and put down on paper.
  • Logging and skidding should as far as possible be assigned to one contractor. This also applies to timber measurement.
  • Especially contractors who are not familiar with the site require more supervision. A detailed instruction of local circumstances and requirements of the forest office/ forestry enterprise is essential. Work instructions have to be written down. Even during the term of contract extensive supervision and control is necessary.
  • The selected working technique has to be in line with the stand, the direction of wind throw and the roading infrastructure. The contractor does not define the roading infrastructure concept, the forestry enterprise does. Requests from the contractor can not be fulfilled.
  • If job performance is unsatisfactory, problems need to be immediately talked through with the contractor. The contractor should be reminded of his/her obligation to remedy deficiencies. The forestry enterprise should stipulate the option to cancel the contract with the contractor. This possibility should be used in authorised cases.
  • The skid road system has to be permanently marked in the stand as well as on a map (if possible calibrated), so that after windthrow external persons (supporting personnel, contractor) can re-establish the skid roads.


  • Additional contractors could be recruited from well known forest ranger colleagues in non-affected areas. Unproblematic implementation of the contact and good work are not guaranteed, but the chances of finding a good and trustworthy contractor will be increased.
  • It may be possible to recruit additional contractors via permanent contractors.


  • Not every machine is appropriate to every operation. Do not use under-dimensioned equipment! Before work begins it must be established which machinery is to be used. To avoid excessive driving, certain machine efficiencies (kW) and machine equipment should be fixed in the contract (e.g. crawler excavators with minimum 100 kW, crane extension ≥ 10 m)!
  • A central contractor-database could lead to more transparency in the contractor market.
  • The work quality of external contractors should be measured against local contractors. Often external contractors were excused from meeting expected standards; however permanent contractors have been required to fulfil these same quality standards for years.
  • Reduce the forest rangers control span down to no more than 3 logging groups (forest workers/ contractors). A thorough preparation, organisation and supervision of the logging operations, as well as monitoring the timer inventory of several crews or contractors is impossible. If continuous logging is necessary or desired and the number of crews/contractors increases, additional support personnel should be assigned to the forest ranger.

Experiences from salvage logging in 1990 and 1999

  1. The contractor's prices should not be inflated by competition from the lower forest administration/ forest offices.
  2. In recent cases of regional storm damaged timber logging (up to three federal states affected) the nationwide available cutting capacity has proven to be adequate. The first offers received might not be the best. Keeping calm and waiting for better offers as well as collecting information and references saves money and eases future working conditions.
  3. Experience showed that the logging process was faster than estimated. Keeping calm and planning logging calmly relaxes personnel and reduces cutting prices.
  4. The cutting process and timber removal need to be co-ordinated. If removal is delayed, timber quality suffers and forest protection problems occur. If in doubt, cutting should be stopped until the timber removal is organised.
  5. Working in windthrown timber requires a high mental and physical effort from forest workers. A rotation of crews after 6 to 8 weeks with reassignment to less exhausting tasks reduces the risk of an accident.
  6. Shortage of timber inventory and operation control of forest worker crews may be reduced by the complete transfer of workers from one district to another (forest ranger, forest workers and tractor).
  7. Standard lengths of long timber ease timber transportation and stack construction at wet storages. With lengths of 18 m all kinds of haulage can be used (depending on the length of the wagon!). If it is clear at the time of logging that the timber will not be transported by railway, it should be cut at the top.
  8. Mechanical bark peeling should be carried out in areas where irrigation capacity is limited or valuable stem timber is present.
  9. Discussion and cooperation with colleagues avoids "district blindness" and helps increase efficiency.
  10. At contract commencement, a detailed instruction of working techniques and quality-standards must be given to contractors. Especially important is agreement regarding settlement and method of log measurement.
  11. The forest enterprise is responsible for maintaining quality standards. The contractor does not define the working technique or the technology to be used. This is determined by the forest ranger on site.

Careful logging

  1. Soil preservation through concentration of operation: prohibit driving across the area during logging and following slash removal.
  2. Utilization of existing skid road system. Strict compliance with skid roads. Therefore it’s necessary to designate skid roads continuously, right from the roadway.
  3. Compliance of skid road distance of 40 m over sensitive soils. The higher costs and associated lower returns are justified by the need for soil protection.
  4. Skid roads shouldn’t be narrower than 20 m on the flat and slightly sloping terrain and narrower than 30 m on slopes.
  5. No new construction of skid roads, even if trees lie in positions difficult to access from the existing skid road system. The higher costs and lower returns from “forced assortments” are justified by of the need for soil protection.
  6. The skid road width has to be as small as possible and should not exceed 5 metres.
  7. Take note of the Soil Protection Act (Bodenschutzgesetz). The forest office is the responsible authority for soil protection under the Soil Protection Act. Take note of the principles of forest road construction for the construction of forest roads and give special consideration to forest biotopes and waterways.
  8. Road maintenance: repair road damage immediately to avoid high future costs.
  9. Conserve driveability of skid roads through the use of high flotation tyres. Before constructing a new skid road, a partial repair of the existing skid road with suitable material should be carried out.
  10. Minimise skidding damages through the selection of approved working techniques, suitable forest technology and appropriate bucking.
  11. Driving on skid roads is only permitted during suitable, dry weather conditions to maintain its driveability. This principle especially applies if there is no brushwood material available to armour the skid road (e.g. at motor-manual logging, in deciduous stands).

Soil protection at logging

  • Intensive familiarisation with the skid road system is necessary before logging begins. It is best to adopt the old skid road system.
  • When clearing the roads (think of the assortment creation!) it might be appropriate to cut a strip at the right and left side of the stand. This marks the old skid road system, which can be used again.
  • Useable skid roads and log trails should be clearly marked. “Wild driving” through the stand must be avoided.
  • The skid road distance has to be at least 20 m.
  • In the state forest of Baden-Wuerttemberg only chain- and hydraulic oils indicated with a "Blue Angel" environment label are allowed.
  • When refuelling chain saws, a fill-in system should be used.
  • The special protection status of the area must be known (to meet water and soil protection requirements etc.).
  • Discharge of oil or fuel is to avoid in every circumstance.
  • Oil binding and absorbing material has to be available.

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