Epsilon Archive for Student Projects

Abstract

In recent decades, continuous cover forestry (CCF) has been (re-)discovered as an important toolbox for promoting biodiversity, helping to deliver a range of ecosystem goods and services as well as to satisfy the needs of various stakeholders. CCF is based on ecological principles and one of its most important tenets is the abandonment of large-scale clearfelling. Despite the demand of various stakeholders to increase the share of productive forest land managed according to CCF in Sweden, CCF has been rarely used in the country to date and knowledge about its methods is lacking. Frame-tree based thinnings are one important part of CCF, since they are useful for promoting complex stand structures and for regenerating stands without clearfelling. So-called frame trees, that correspond to the silvicultural objective(s) of a forest stand are selected and permanently marked. These trees exclusively profit from all silvicultural operations and are to remain in the forest until final harvest or natural death. Immediate competitors in the vicinity of these frame trees are then selected for eventual removal. Marteloscopes are forest research plots where all trees are measured and numbered. Over the last twenty years marteloscopes have become an important component of CCF training and are widely used in many countries. I established a marteloscope in the Svartberget experimental park, close to Umeå in northern Sweden and carried out an experiment involving 13 test persons with and without forestry background. The objective of this experiment was to investigate, whether the participants would be able to select trees for a frame-tree based thinning without prior practical training. I measured the participants’ agreement in tree selection and studied to what degree their tree selection corresponded to the theory of frame-tree based thinnings. Since the silvicultural and the experimental situation in Sweden today is similar to that in Great Britain twenty years ago, I contrasted the results of the Swedish experiment with the results of 26 marteloscope experiments carried out in Great Britain. Constructing such a statistical contrast is a useful step for identifying specific training needs when introducing CCF to Sweden. The overall agreement was rather low in all experiments. The participants’ tree selection in the Swedish experiment was closer to the theory of frame-tree based thinnings than it was for the British experiments, especially in case of competitor trees. Still, training is needed especially with regard to frame tree resilience and appropriate thinning intensity in the future. Additional experiments with larger and more diverse groups of participants could lead to further, more differentiated results and would allow comparisons between different groups of persons involved in forest management.