Model for increasing timber value is widely implemented in forestry

Matching the harvested trees with sawmill demand has always been important for the forest industry and the demands for responsible, resource-efficient forestry make the issue more relevant than ever. In 2023, a model was launched that increases the accuracy of matching without requiring investments in new expensive technology - now it is being implemented on a wide scale.  

- This could well be a new Swedish record in implementation, says Björn Hannrup, senior researcher at Skogforsk. In 2023, we released the code for the prototype programme that can increase the timber value of the harvested forest by better matching the harvested trees with the demands of the sawmills. It is now being widely implemented in the forestry sector and becomes part of the harvesters' control and measurement system. The point is that the implementation is neither expensive nor complicated, no new equipment is required and the prototype programme works with the existing standards. 

To start from the beginning, the harvested logs need to match the demands of the sawmills, only then can the trees be used resource-efficiently and meet the requirements of profitability and sustainability. During harvesting, the forest machine collects data on the diameter and length of the log, the most important parameters in this process of matching, and the information on which the harvester optimises its work. To estimate the accuracy of the measurement data, the machine operator also makes a control measurement of one trunk per day.  

- This is where the challenge lies. The requirements of sawmills have become increasingly specific and diverse. The demands for more responsive systems and for real-time detection of deviations are higher than what the current solutions can deliver, says Björn Hannrup.  

Laying the foundation for automated functions

To meet this challenge, the researchers have developed a model that uses the machine's own measurement data and compares it to an 'ideal log', and to Biometria's database of timber measurements. Biometria is a membership-owned company that impartially measures forest products. 

- We get a model that describes measurement accuracy based on the harvester's total production, instead of basing it on the driver's random sample. This lays the foundation for automated functions such as warning the driver in the event of deviations. But it does not stop there, the model can also assess how good or bad the deviation is, says Björn Hannrup. 

'An unbelievable strength that we can use the machine's own data'

In a Mistra Digital Forest project, the model was tested for 18 months on 15 harvesters in Vida Skog's holdings. An important part of the study has been developing the key indicators that users believe provide relevant information, in dialogue with the machine operators who tested the prototype. The study also showed that final felling harvesters made more accurate measurements than machines used in both thinning and final felling; the larger the log, the worse they performed. It was also found that driving style and forest characteristics affect accuracy. 

- We are extremely satisfied with the project and are now preparing for a comprehensive implementation. It is an incredible strength that we can use the machine's own data, it clearly improves how well the monitored timber corresponds to the desired output from the sawmill. Currently, before everything is in place, we are already using the information to provide feedback to drivers and contractors about adjustments in driving style and to the prevailing terrain. In-house, we are communicating the importance of choosing the right machine for the right forest, says Fredrik Carlsson, forestry specialist at Vida Skog.  

Back to Björn Hannrup:

- We now have a model that can contribute to profitability and sustainability throughout the wood mechanics value chain.