1. Department of Bioenergy, Swedish University of Agricultural Sciences, P.O. 7060, SE 75007 Uppsala, Sweden.
2. Department of Forestry and Natural Resources, Purdue University, Pfendler Hall, West Lafayette, IN, 47907 USA.
3. Ecotechnology, Mid Sweden University, SE 83125 Östersund, Sweden.
4. Unit for Field-based Forest Research, Swedish University of Agricultural Sciences, Asa Forest Research Station, SE 36030 Lammhult, Sweden.
5. Department of Forest Soils, Swedish University of Agricultural Sciences, P.O. 7001, SE 75007 Uppsala, Sweden.