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Small diameter wood utilization with innovative stand management for multifunctional forests and a growing sustainable bio-economy

Coordinator: Tomas Nordfjell, Swedish University of Agricultural Sciences (SLU)/ Department of Forest Biomaterials and Technology, Sweden
tomas.nordfjell (at) slu.se

Other partners: ES, FI, SI
Project duration: 02/2019-06/2022

Project abstract:

Biomass derived from small-diameter, dense, thinning stands (SDS) is largely underutilized within EU, mainly because of in-effective harvesting methods, leading to high costs. Post-wildfire regenerated Mediterranean stands have a high risk of wildfire recurrence. The objective was to develop and evaluate new technologies and business and operational models that can support a sustainable management and utilization of different types of small diameter wood. The efficacy of boom-corridor thinning (BCT) and selective thinning (ST) on felling and bunching productivity was compared in thinning of whole tree biomass in SDS. BCT working method is when trees are cut with linear movements of the harvester’s boom reach, along narrow corridors, instead of cutting each tree selectively (ST). Trials were performed in Sweden, Finland, Slovenia, and Spain using the same machine and operator. A collector-bundler BioBaler was compared with a chain mulcher performing systematic mulching in a Pinus pinaster stand in Spain.

A questionnaire to acquire information about factors motivating forest owners to utilize SDS resources was done. Results: it is possible to achieve economy when thinning SDS while improving the development potential of the remaining stand. BCT with Bracke C16 felling and accumulating head at the tip of the boom is an efficient work method. Tree and soil damages as well as greenhouse gas emissions in the thinning treatments was acceptable low, but BCT gave more favourable results than ST. Under the studied conditions, BioBaler was not economically competitive with the conventional treatment (chain mulching), because of low collection efficiency.

The perception among private forest owners is mainly positive towards BCT, but SDS management may not be attractive as a stand-alone activity. Forest owners’ associations are advised to consider their role in supporting different owner types in their SDS management. The perception within forestry companies or state forestry is more varied.

BCT may become the normal first thinning, but only under the condition that there is a long-term demand for forest biomass in the form of unbranched small trees.

Project website: link
Project presentation at ForestValue kick-off seminar 23-24 May 2019: pdf
SMALLWOOD promotional videos, subtitles in five languages: link
Stakeholder Article 1 SMALLWOOD – Cost analysis of thinning and supply systems for small diameter trees
Stakeholder Article 2 SMALLWOOD – Capitalizing HEI potentital usability – Stakeholder workshops
Stakeholder Article 3 SMALLWOOD – Sustainability and value creation rating
For more reports and infosheets, please see SMALLWOOD website