Biography

The majority of my work at NIBIO has revolved around managing and analysing large data sets. This work can be categorised into three main areas: analysing StandForD-files from forest machines, conducting extensive simulations of forest machines, and studying CANBUS data from timber trucks. In addition to this work, I have participated in more traditional forest operation research, such as time studies and work quality measurements.

Previus experiance
My academic journey began at the Swedish University of Agricultural Sciences (SLU), where I pursued a forester education (Master of Science in Forestry). My studies focused on raw material supply and production planning. I furthered my education at SLU with PhD studies in forest technology, considering "Technology and Systems for Stump Harvesting with Low Ground Disturbance". Following my PhD, I spent a year as a postdoctoral researcher at the University of Tokyo. There, I worked with small forwarders in steep terrain. I then returned to SLU to work on logistics around terminals and the transfer of GIS knowledge.

My PhD project, in more detail, included measuring ground disturbance, simulating the productivity of different stump harvesting systems, analysing costs, developing an experimental rig for stump twisting, and conducting time studies. This PhD project was part of the research school FIRST, which led me to spend a year on other research studies. These studies encompassed measuring temperature and gas emissions during the storage of peat and sawdust, conducting productivity studies, and investigating the variation in moisture content of forest fuel chips to estimate the necessary number of samples for different measurement precision. As a post-doc, my work included productivity studies and cost analysis of Japanese forwarders and separate loaders in steep terrain. I also collaborated on a study about the comminution of forest fuel. During my second tenure at SLU, I work with the potential benefits of open terminals and conducted an economic evaluation of different terminal locations, considering harvest, transportation, and capital costs.

Read more
To document

Abstract

Butt rot is a main defect in Norway spruce (Picea abies (L.) Karst.) trees and causes large economic losses for forest owners. However, little empirical research has been done on the effects of butt rot on harvested roundwood and the magnitude of the resulting economic losses. The main objective of this study was to characterize the direct economic losses caused by butt rot in Norway spruce trees for Norwegian forest owners. We used data obtained from seven cut-to-length harvesters, comprising ∼400,000 trees (∼140,000 m3) with corresponding stem profiles and wood grade information. We quantified the economic losses due to butt rot using bucking simulations, for which in a first case, defects caused by butt rot were included, and in a second case, all trees were assumed to be free of butt rot. 16% of trees were affected by butt rot, whereby butt rot tended to occur in larger trees. When butt rot was present in a tree, the saw log volume was reduced by 48%. Proportions of roundwood volume affected by butt rot varied considerably across harvested stands. Our results suggest that butt rot causes economic losses upwards of 7% of wood revenues, corresponding to € 18.5 million annually in Norway.

Abstract

Normal log lengths in Norway are 3–6 m (NL), but occasionally there is a demand for short timber with a 2.5 m log length (ST). There are concerns that ST could reduce the forwarders' productivity. Six type stands were created based on harvester data. Different assortment distributions, conditions, and forwarders were simulated in each type stand. It was found that an additional ST assortment almost always decreased productivity (from –15.5 to +4%). Increased forwarding distance (m), more difficult driving conditions, and increased log concentration [m3·(100 m strip road)–1] decreased the productivity difference between sites with ST and NL and sites with only NL. Increased forwarder size increased the productivity difference between sites with ST and NL and sites with only NL. It is possible to load two stacks of ST on some forwarders. Such loading was more productive than loading one stack on longer forwarding distances, while the opposite was the case on short distances. However, loading two stacks of ST can lead to overloading.

To document

Abstract

Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders’ loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple’s accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple’s usability will be improved by adding an own rocker switch on the forwarder’s controls to command the extra claws.