Vegetational succession in a South Swedish deciduous wood

Summary

The study deals with a small South Swedish deciduous wood (Ulmo-Fraxinetum, Sjögren n.p. 1971), a national park which has been left almost undisturbed during the last 60 years. Since 1925 the number of vascular plants in the area has diminished by 42%. In the tree layerUlmus andFraxinus have increased since 1918 whileFagus has remained fairly constant andQuercus, the former dominant, has become much less important. In the shrub layer youngUlmus are predominant, while the former dominantsCorylus andCrataegus, have diminished markedly. Vegetation analyses of the field layer laid out in a fixed grid system in the years 1935, 1969/70 and 1975/76 show a decrease in both the total number of species recorded and in the number of species per sq. m.Anemone ranunculoides, Aegopodium podagraria andMercurialis perennis are species which have expanded while e.g.Anemone nemorosa, Lamium galeobdolon andGeum urbanum have diminished. Increased shading from the closer tree canopies, increased litter fall, and lower temperature at the soil surface are changes in environmental factors which probably have come about sine 1935 and may be especially important for the field and bottom layer species. The results are discussed in relation to the stability of an ecosystem and to the management of nature reserves.

Lennart Lindgren and Stefan Persson were responsible for the project in 1969–1970 and 1975–1976, respectively. They compiled all the material from these investigations. Skilful assistance was given by Brita Billstein, Mimmi Varga and Tommy Wikberg.