1. Oxford Systematic Reviews LLP, Oxford OX2 7DL, UK
2. Sylva Foundation, Little Wittenham, Oxfordshire OX14 4RA, UK
3. Long-Term Ecology Laboratory, Department of Biology, University of Oxford, Oxford OX1 3SZ, UK
4. Forest Research, Northern Research Station, Roslin, Midlothian EH25 9SY, UK
5. School of Archaeology, University of Oxford, Oxford OX1 2PG, UK
6. Forest Research, Alice Holt Lodge, Farnham, Surrey GU10 4LH, UK
7. Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
8. Forest Research, 620 Coldharbour Lane, Bristol BS16 1EJ, UK