Harvester data, that is the data collected from the forestry machine during thinning or final felling, offers many exciting possibilities. One example of an opportunity like that, is to combine data from the harvester with data from remote sensing, something Jon Söderberg, doctoral student at Skogforsk, is working on within Mistra Digital Forest.
Jon Söderberg, doctortal student at Skogforsk.
– In our study, we wanted to investigate the possibilities of estimating a number of forest variables, such as stem volume and basal area*, at the stand level for standing mature forest, for example. This is done by combining measurement data from felled trees and positioning data from final fellings, with remote sensing data. In this case, we used data from the national airborne laser scan carried out by Lantmäteriet, says Jon Söderberg, doctoral student at Skogforsk.
According to Jon Söderberg, the results of the study turned out well. It was found that harvester data from previous harvest operations can be combined with laser data and give good estimates, even when the positioning information is only approximate. He says they recognised that positional uncertainty affects the determination of the boundaries of felled areas, and that there is room for improvement. In addition, the dimensions and quality recorded for each log is valuable information. That information can be used for yield calculations – that is, the estimation of timber volume and pulpwood volume from a planned felling.
How can these results be passed on to the industry?
– Because Skogforsk supports the forest companies in the implementation of applications based on harvester data, such as forest estimates and yield calculations, the results of the work are anchored in forestry. In addition, information about the work is disseminated at forest conferences, Jon Söderberg explains.
He sees that the next step within the framework of Mistra Digital Forest will be to proceed with a study of yield calculations based on the same data sources, and also to explore the benefits of a denser laser scan.
– In this case we will investigate whether information about height and diameter distributions for the trees in the stand can provide better estimates. Better tree positioning is technically possible but not commercially available yet. An interesting question is what effect better tree positioning has for remote sensing estimates made with the help of harvester data from test machines that are in operation today, Jon Söderberg concludes.
* Basal area is a measure of how dense the forest is.
Read the full scientific article.