“…We introduced harvesting costs and harvesting cost volatility as additional instrumental variables. Hultkrantz (1987), Faminov and Benson (1990), Palander (1995), Roehner (1996), Cea and Jofre´(2000), Troncoso and Garribo (2005) Mill capacity Physical processing capacity Volume of roundwood supplied by UPM Kymmene Metsa¨H ultkranz and Aronsson (1989), Bergman and Lo¨fgren (1991), Bra¨nnlund (1991), Bra¨nnlund (1993), Cea and Jofre´(2000), Kallio (2001), Størdal and Baardsen (2002), Troncoso and Garribo (2005) Roundwood price Market price of different roundwood assortments UPM data on the annual average roundwood price by species (birch, spruce, pine) and assortment (pulpwood, sawlogs) for each timber supply area Bra¨nnlund et al (1985), Martinello (1985), Lo¨fgren and Ranneby (1987), Hultkranz and Aronsson (1989), Bergman and Lo¨fgren (1991), Bra¨nnlund (1991), Hetema¨ki and Kuuluvainen (1992), Kuuluvainen et al (1996), Toppinen and Kuuluvainen (1997), Toppinen (1998a), Gomez et al (1999), Cea and Jofre´(2000), Latta and Adams (2000), Bolkesjo and Solberg (2003), Lundmark and So¨derholm (2003) Price volatility Standard deviation of roundwood prices within each timber supply area UPM data on annual roundwood price by species and assortment for 4-5 sub-units per timber supply area. Roehner (1996), Gomez et al (1999), …”