The original version of this chapter was revised: The copyright line was incorrect. This has been corrected. The Erratum to this chapter is available at DOI: 10.1007/978-0-387-35514-6_15 A MODEL WHICH INTEGRATES STRATEGIC AND TACTICAL ASPECTS OF FOREST HARVESTING Alastair McNaughton Division of Science and Technology Tamaki Campus, University of Auckland, Private Bag 92019, New Zealand a.mcnaughton@auckland.ac.nz Mikael Ronnqvist Division of Optimisation, Linkoping University, 58183 Linkoping, Sweden miron@math.liu.se David Ryan Department of Engineering Science, University of Auckland, Private Bag 92019, Auckland, New Zealand d. ryan@auckland.ac.nz Abstract The forest harvesting problem involves the construction of a schedule for felling the individual blocks of trees which comprise a large commercial plantation. A strategic model sets long-term harvesting goals in terms of total area to be cut each year, but fails to identify individual blocks. A tactical model produces a short-term schedule of actual blocks. Unt.il recently, most planning by forest managers has involved these as two separate models, often resulting in contradictory recommendations. v'\'e present an integrated model, which embraces both strategic and tactical decisions, which can be solved by optimisation methods. This model achieves a detailed formulation by means of a non-stan- dard column generation structure. The solution algorithm solves the resulting relaxed linear program formulation. This is then combined M.J.D. Powell and S. Scholtes (Eds.), System Modelling and Optimization: Methods, Theory and Applications. © 2000 IFIP International Federation for Information Processing. Published by Kluwer Academic Publishers. All rights reserved.