Södra has been following up planting assignments for several years. This has shown that, on average, 25 percent of the seedlings die within three years of planting. There are many factors that affect seedling survival, including how the scarification is performed and where and how the seedlings are planted in the soil.
If seedling survival is improved, more seedlings will reach production maturity and the rate of forest growth will increase. In 2018, Södra’s Board decided to make an investment to improve the quality of forest regeneration, an initiative that is also intended to achieve the target of a 20 percent higher rate of forest growth on members’ estates between 2015 and 2050.
Södra started using Bracke P11 (an excavator-based planting machine) on members’ land in 2006, which demonstrated excellent results for seedling survival. Despite not gaining ground for various reasons, the method showed clearly that planting seedlings with a mechanical planter was fully possible.
Södra decided to develop a specific method for southern Sweden that made it possible to scarify and plant in the same concept. That is how the BraSatt project started.
Magnus Petersson, Head of Contractor and Technology Development, tells why Södra wants to invest in a new regeneration method.
“We want to achieve a precise scarification process. Then we only need to scratch the topsoil, but the growing conditions in that spot must be as optimal as possible for the seedling. The seedling should be planted at the same time, so that it automatically lands in the best planting spot. Then the regeneration process will be both efficient and less disruptive. This will be achieved with high levels of expertise and knowledge
of new methods in a wide range of areas, including areas not related to forestry,” he said.
The aim of BraSatt is to develop a scarification and planting method that ensures a high rate of seedling survival and is gentle on both humans and the soil. The intention is to build a prototype machine, with field testing beginning in the planting season of 2023. The aim is to create a good work environment for the operator by developing a machine that is as self-propelled as possible. There are many technologies in various industries that could also be useful in forestry, especially big data processing. An important part of the project is to study what is needed to make the method attractive to sellers, buyers and users and allow that to guide both the design and choice of technology.
During the project, we developed a concept and demonstrated a new method of scarification in the field. The autonomous planting was developed from the BraSatt 01 prototype. The idea is that the proposed machine will follow an overall route, find an accessible path through the terrain, select good planting spots, feed the seedlings through the system, scarify the soil and then plant successfully. BraSatt has therefore covered the entire chain – from planning to planting the seedlings in the soil.
The project has also developed a new method of scarification that is optimal for seedlings and energy-efficient, while also leaving a relatively even clearing behind. This method affects a considerably smaller section of the surface compared with the current method. Another important part of the development process was to account for the human-machine interaction and factor in the operator’s role in creating a good work environment. The operator’s new role will be to work together with the machine,
to provide support when it asks for help, to plan the work on the clearing and to work with seedling care.
Now that field testing is completed, it is time to put everything together, document and analyse in order to find possible ways forward.
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