Vegetation changes between the 1940's and 1992 in three upland sites in Wales, assessed from aerial photographs : final report /
Norris, D. A.
Radford, G. L.(Geoffrey L.),1944-
Stevens, P. A.
Countryside Council for Wales.
Institute of Terrestrial Ecology.
Natural Environment Research Council (Great Britain)
Bangor : Institute of Terrestrial Ecology,
1997.
ITE Project T08077w5.
CCW Contract FC73-01147.
Vegetation dynamics