Digital technology to provide better insight into the condition of forest roads

Private roads in poor condition risk becoming a costly issue, both for forestry and for the environment. At present, we know relatively little about the condition of these roads, but researchers are currently developing methods that could improve the prospects for road maintenance and harvesting planning.

Many of the country’s forest roads are starting to show their age. Most were built in the latter half of the 20th century and are now struggling with a maintenance deficit that affects forestry transport. The load-bearing capacity for heavy vehicles is often limited for much of the year, and the poor standard also affects the many homeowners living alongside the roads.

– One fundamental problem today is the lack of adequate road information, which means we cannot plan maintenance sufficiently well. The road network is absolutely crucial to forestry, and logging operations are planned according to the vehicles’ ability to get around in the terrain. If we do not know enough about the road, it can lead to unnecessary damage to the road surface, and risks transport vehicles having to turn back without completing their assignment. All of this is costly for the environment, for the road authorities and for forestry companies alike, says Daniel Noreland, a researcher in production and supply systems at Skogforsk.

Pilot test points towards desk-based pre-planning 

With support from Mistra Digital Forest, Skogforsk is investigating whether remote sensing data and other tools can be used both for new inventory surveys, and also for keeping information about the roads up to date. One study uses the soil type map, the soil moisture map and laser data which includes, among other things, information about ditches.

– We have carried out a pilot test in which we assess the load-bearing capacity of roads using this type of data. Everything points to the fact that, in the long run,we could carry out a large part of the preliminary planning prior to a felling operation from an office desk, says Daniel Noreland.

Forestry stakeholders call for an inventory method for private roads 

A method development group comprised of forestry stakeholders is currently driving the development of an inventory method for the private road network in Svealand and Norrland. There is already comprehensive information available on private roads in Götaland, following an extensive field inventory project. Going out into the field once again to do another inventory of the roads would be far too time-consuming, besides which the new digital technology opens the door to more efficient solutions.

– There is a clear case for improving the information about individual roads. A rough estimate suggests that inadequate road information costs one krona per cubic metre of timber harvested. Sweden’s annual harvest stands at around 85 million cubic metres, says Lars-Erik Jönsson, transport manager at Biometria, and head of the methodology development group.

He calls for an automated method that simplifies and streamlines access to road information, with the key requirement that quality is not compromised in the process.

- As far as possible, road conditions should be assessable remotely. However, one step towards achieving this could be a model that identifies critical sections, for example, then we can go out and do on-site surveys where they are needed, says Lars-Erik Jönsson.”

Extensive work to improve the information about forest roads 

Skogforsk is also investigating how data from the engine management systems of trucks can be used to estimate accessibility. By monitoring how rolling resistance changes when the road surface becomes softer, for example after rain, it is possible to continuously assess the condition of the road. Topographical data is also important. In 2026, Sweden’s national road database will be getting better topographical information, which in the long run could improve data quality in projects of this kind.

- Extensive work is underway to improve information about forest roads so that forestry becomes safer, more efficient and that damage to the roads can be reduced, concludes Daniel Noreland.