Thinning intensity, timing and tree selection can substantially influence forest growth and the rate of carbon sequestration. Remote sensing‑based forest planning increasingly incorporates tree‑level estimates alongside stand‑level assessments so information on the status of the trees must be transferred effectively to the harvester operator. This doctoral thesis evaluated the current state of development of tree-level operator guidance systems based on mobile laser scanning (MLS) and their potential to improve thinning operations in the future.
Study I examined the effect of prior tree marking on cutting productivity and harvesting quality in thinnings. Prior tree marking increased cutting productivity by an average of 2.7–2.8% through reduction in the time spent during the boom‑out and moving, and also helped the operator maintain the target density of the remaining trees.
Study II investigated the effect of tree-level guidance (with the laser scanning-based thinning density assistant (TDA) system from Ponsse Plc.) on cutting productivity in thinnings, the workload experienced by harvester operators and the overall profitability of the investment. At the pioneering implementation stage, the guidance system modestly improved productivity (by 1.0–1.2%), and less experienced operators reported benefiting from the system. Improved implementation could unlock greater benefits in both productivity and harvesting quality.
Study III evaluated the capacity of MLS to measure harvesting quality attributes and to improve harvesting quality with the TDA in thinning stands. The results showed strong agreement between MLS‑based assessments and traditional field measurements, while also highlighting the need to develop new methodologies. Harvesting quality met the recommendations for sustainable forest management on almost all reference and TDA plots.
The findings show that tree‑level guidance can improve operators’ productivity by 1–3% while helping to maintain good harvesting quality, with greater benefits achievable through improved usability and a more immersive user experience. However, achieving investment feasibility requires other, intangible value streams both from and to all stakeholders.