Understorey vegetation in fresh and herb-rich upland forests in southwest Lapland.

摘要

Fresh and herb-rich upland forest sites in the northwestern part of the central boreal vegetation zone in Finland were studied with respect to vegetation structure and vegetation–environment relationships (soil, stand characteristics). Two fresh heath vegetation data sets, one from the northern boreal zone and the other from the central boreal zone, were compared with the data of this study using multivariate methods. The variation in heath forest vegetation within the climatically uniform area was mainly determined by the fertility of the soil (in this case primarily Ca and Mg) and the stage of stand development. The N, P and K content of the humus layer varied little between the vegetation classes. Fertile site types occurred, in general, on coarser-textured soils than infertile site types, may be due to the fact that the sample plots were located in various bedrock and glacial till areas, i.e. to sampling effects. The place of the vegetational units of the study area in the Finnish forest site type system is discussed. The vegetation of the area has features in common with the northern boreal zone as well as the southern part of the central boreal vegetation zone. The results lend some support to the occurrence of a northern Myrtillus type (p.MT) or at least that intermediate forms of fresh and herb-rich mineral soil sites commonly occur in the studied area. It is argued that the older name Dryopteris-Myrtillus type (DMT) is more suitable than Geranium-Oxalis-Myrtillus type (GOMT) for herb-rich heath sites in the study area.