1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), SE‐901 83 Umeå, Sweden
2. Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences (SLU), SE‐901 83 Umeå, Sweden
3. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE‐901 83 Umeå, Sweden