British Wildlife. A magazine for the modern naturalist (6 issues per year). British Wildlife Publishing.
BSBI Handbooks. A series of identification guides to selected plant groups or families. Botanical Society of the British Isles.
Edlin, H.L. (1970). Trees, Woods and Man (New Naturalist Series, no. 32). Collins.
Fitter, A. (1978). An Atlas of the Wild Flowers of Britain and Northern Europe. Collins.
Fitter, R., Fitter, A. and Blamey, M. (1974). The Wild Flowers of Britain and Northern Europe. Collins.
Gibbons, R. and Brough, P. (1992). The Hamlyn Photographic Guide to the Wild Flowers of Britain and Northern Europe. Hamlyn.
Johnson, O. and More, D. (2004). Tree Guide. HarperCollins.
Morton, A. (2004). Tree Heritage of Britain and Ireland. Airlife.
Preston, C.D., Pearman, D.A. and Dines, T.D. (2002). New Atlas of the British & Irish Flora. Oxford University Press.
Rose, F. (illustrated by Davis, R.B., Mason, L., Barber, N., and Derrick, J.) (1981). The Wild Flower Key. Warne.
Spooner, B. and Roberts, P. (2005). Fungi (New Naturalist Series, no. 96). HarperCollins.
Stace, C. (1997). New Flora of the British Isles (second edition). Cambridge University Press.
Tubbs, C.R. (1986). The New Forest (New Naturalist Series, no. 73). Collins.
The following list includes organisations that I have found useful in the context of trees, woodland and conservation:
Ancient Tree Forum www.woodland-trust.org.uk/ancient-tree-forum
Botanical Society of the British Isles (BSBI) www.bsbi.org.uk
Bramley Frith www.bramleyfrith.co.uk
The Forestry Commission www.forestry.gov.uk
The National Trust www.nationaltrust.org.uk
The National Trust Heritage Trees www.nationaltrust.org.uk/main/w-chl/w-countryside_environment/w-woodland/w-woodland-heritage_trees.htm
The National Trust for Scotland www.nts.org.uk
Royal Society for the Protection of Birds (RSPB) www.rspb.org.uk
The Wildlife Trusts www.wildlifetrusts.org.uk
The Woodland Trust www.woodland-trust.org.uk
The beautiful patterns in spalted birch timber are created by fungal decay.