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We present an agent-based model of wood markets and show our efforts to validate this model using empirical data from different sources, including interviews, workshops, experiments, and official statistics. Own surveys closed gaps where data was not available. Our approach to model validation used a variety of techniques, including the replication of historical production amounts, prices, and survey results, as well as a historical case study of a large sawmill entering the market and becoming insolvent only a few years later. Validating the model using this case provided additional insights, showing how the model can be used to simulate scenarios of resource availability and resource allocation. We conclude that the outcome of the rigorous validation qualifies the model to simulate scenarios concerning resource availability and allocation in our study region.

For this study, 18 permanent research plots in Switzerland with an area between 0.5 and 2.5 ha that have been installed between 1905 and 1931 were analysed using annuities. The plots cover a wide range of uneven-aged forest-types from pure Norway spruce to classical single-tree selection (plenter) forests dominated by Silver fir in different elevations (575-1810 m a.s.l). The areas have been managed according to an uneven-aged silvicultural system and growth and yield characteristics have been assessed on a single-tree basis every 5-11 years. Net revenues of timber harvesting were computed as a time series from the installation of the plots until today and transformed into net present values and subsequently into annuities for each assessment interval. Three types of annuities: (1) for cutting cycles; (2) forward; (3) backward for the whole assessment period were calculated together with internal rates of return. The results display that annuities were usually positive with an interest of 2 per cent. High elevation (>1400 m) Norway spruce dominated forests as well as heavily overstocked (>900-1000 m3 ha−1) plots showed the lowest or even negative annuities. The reduction of overstocks lead in the mid-term to an increase, but resulted in a short-term decrease of the annuities. For many of the research plots, especially those in higher elevations, there is a trend towards an increase of the annuities over time. The highest annuities were found in Silver fir dominated selection forests with a growing stock close to or slightly above an equilibrium structure. The backward calculation of the annuities improved for some plots the problem of the strong influence of the value of the initial growing stock. Implications for uneven-aged silviculture as well as for the analysis of the economic performance of uneven-aged and even-aged forests and the application of annuities are discussed in the paper

Agent-based modeling is a promising method to investigate market dynamics, as it allows modeling the behavior of all market participants individually. Integrating empirical data in the agents’ decision model can improve the validity of agent-based models (ABMs). We present an approach of using discrete choice experiments (DCEs) to enhance the empirical foundation of ABMs. The DCE method is based on random utility theory and therefore has the potential to enhance the ABM approach with a well-established economic theory. Our combined approach is applied to a case study of a roundwood market in Switzerland. We conducted DCEs with roundwood suppliers to quantitatively characterize the agents’ decision model. We evaluate our approach using a fitness measure and compare two DCE evaluation methods, latent class analysis and hierarchical Bayes. Additionally, we analyze the influence of the error term of the utility function on the simulation results and present a way to estimate its probability distribution.

Im Artikel werden produktions-, industrie- und institutionenökonomische Ansätze zur Untersuchung des Marktverhaltens öffentlicher Forstbetriebe in den Kantonen Graubünden und Aargau vorgestellt. Ziel ist es, das Verhalten der Holzmarktakteure besser zu verstehen und die Verfügbarkeit des Rohstoffes unter verschiedenen Rahmenbedingungen zu beurteilen. Die Analyse basiert auf Befragungen sowie Entscheidungs- und Vertrauensexperimenten. Neben strukturellen Merkmalen des Waldes werden forstbetriebliche Aspekte sowie Marktstrukturen und institutionelle Besonderheiten aufgezeigt. So variiert nicht nur die Nutzungsintensität in den beiden Kantonen stark, sondern es unterscheiden sich auch die bevorzugten Absatzstrukturen für die Sortimente. Während das Bündner Stammholz zu rund 80% über Bündelungsorganisationen und Forstunternehmer vermarktet wird, überwiegt im Aargau die Direktvermarktung mit knapp 70%. Dabei dominieren in beiden Kantonen langjährige Geschäftsbeziehungen. Die präsentierten Ergebnisse fliessen in die computergestützte Analyse verschiedener Holzmarktsituationen ein.

To be able to estimate the commercial wood assortment of forests at all times is an important requirement of economical wood production. This makes it possible to improve management decisions by quantifying the revenues of alternative silvicultural and bucking strategies. So far a functional simulaton instrument for bucking single trees and whole stands was missing in forestry and in forest science in Switzerland. The SorSim bucking simulator of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) fills this gap. SorSim is implemented in Java and is platform-independent. An overview is given how the simulator works. Two examples show applications in practice and science. Of particular value is the possibility of estimating wood assortments of planned harvesting operations based on simple timber marking protocols. Especially in science and in strategic planning, SorSim allows the analysis of the long-term development of revenues of forest stands given different silvicultural methods. Combining SorSim with IT-based harvesting productivity models provides greater insight. Further development of SorSim entails testing different optimization approaches, e.g. single tree bucking to value and whole stand bucking to order.

For this study, 18 permanent research plots in Switzerland with an area between 0.5 and 2.5 ha that have been installed between 1905 and 1931 were analysed using annuities. The plots cover a wide range of uneven-aged forest-types from pure Norway spruce to classical single-tree selection (plenter) forests dominated by Silver fir in different elevations (575-1810 m a.s.l). The areas have been managed according to an uneven-aged silvicultural system and growth and yield characteristics have been assessed on a single-tree basis every 5-11 years. Net revenues of timber harvesting were computed as a time series from the installation of the plots until today and transformed into net present values and subsequently into annuities for each assessment interval. Three types of annuities: (1) for cutting cycles; (2) forward; (3) backward for the whole assessment period were calculated together with internal rates of return. The results display that annuities were usually positive with an interest of 2 per cent. High elevation (>1400 m) Norway spruce dominated forests as well as heavily overstocked (>900-1000 m3 ha−1) plots showed the lowest or even negative annuities. The reduction of overstocks lead in the mid-term to an increase, but resulted in a short-term decrease of the annuities. For many of the research plots, especially those in higher elevations, there is a trend towards an increase of the annuities over time. The highest annuities were found in Silver fir dominated selection forests with a growing stock close to or slightly above an equilibrium structure. The backward calculation of the annuities improved for some plots the problem of the strong influence of the value of the initial growing stock. Implications for uneven-aged silviculture as well as for the analysis of the economic performance of uneven-aged and even-aged forests and the application of annuities are discussed in the paper