fulltext - DiVA

Regional a.spects on the flora 225Others are seldom found in other parts of thewoodland than the west:Alchemilla glomerulansAlchemilla murbeckianaGarex BigelowiiJuncus biglumisJ uncus triglumisGera.stium alpinumOxyria digynaPedicularis lapponicaPhyllodoce coeruleaSedum roseaIn north.ern and central Lappland a "pre-alpineconifer forest subregion" occupies considerablehigh-level, chiefly western and northern parts ofthe woodland east of the Scandes. Around lowmountains (see WISTRAND's contribution) and onthe highest parts of wooded morainic ridges thesepre-alpine coniferous forests cover wide areas, butchiefly they consist of heath forests poor in species.There are large areas of pre-alpine coniferous forestalso within the Scandes, i.e. to the west of theCaledonian border. (These pre-alpine areas of theScandes, which are most extensive in the south ofLappland, and are considerably richer in speciesthan the woodlands dealt with in this article, aretreated in this book by 0. RuNE.) The presence ofScandian plants in the high-level coniferous forestsof woodland Lappland east of the Scandes is sparse(much sparser than on the river banks in thewoodland) but Lycopodium alpinum, Phyllodocecoerulea, Arctostaphylos alpina, Carex Bigelowiiand Pedicularis lapponica grow rather regularly inpre-alpine dwarf-shrub heath forest, within theparts close to the Caledonian border. On the easternmostmountains and high morainic ridges, in contrast,these species are rare or completely absenteven in the pre-alpine conifer belt.Floristic boundaries, a discussionThe lower limit for the pre-lpine coniferousforests is hard to distinguish. GuNNAR ANDERSSON(1905, p. 61) drew it where the spruce and the pinereach their normal development. He says, "if onetries to find a true biological border for the prealpineforest one surely experiences the fact thatsuch a border can be found only in extremely fewplaces. Nature makes no more jumps here than inother cases. The character of the forest shifts onlygradually, and therefore there can be no borderbelts or lines" (original Swedish). SERNANDER (1922,p. 253) connected the lower limit of the pre-alpinesubregion with the Ledum border. HEINTZE (1913)delimited a "subsilvine" zone. DEGELIUS (1932),Du RrETZ (1942 b, 1950e, 1952, 1964, etc.), Wr­STRAND (1962, p. 40) and others also deal with thepre-alpine subregion. Du RIETZ (1952, p. 7) givesan elevation of about 350 m as the lower limit ofthe pre-alpine conifer forest in northern Lappland(Gallivare). SJ6Rs (1950b, p. 117) says: "Betulaverrucosa may be mentioned as a species that hardlyreaches the upper subregion", and later (1963a)compares this line with the economic limit forartificial regeneration on State forests (H6JER 1954).In Lule Lappmark Betula verrucosa, Ledumpalustre, Carex globularis, Juncus stygius and Rosamajalis have a similar horizontal distribution withtheir western limits nearly coinciding. They reachclose to the pre-alpine coniferous forest but nofarther west. Conditions are, however, different inother parts of Lappland. Thus for instance Vacciniumoxycoccus in the south of La ppland is a gooddifferential species, being absent in the pre-alpinesubregion and present in the central North-Swedishconifer forest subregion (sensu Du RIETZ l950e),whereas in Lule Lappmark the farthest westernstations lie about lOO km east of the Caledonianborder.When determining the lower limit of the subregionconsidered it is not enough to know thehorizontal distribution of these species. One mustah:!o know how high for instance Ledum palustre,Betula verrucosa and Carex globularis ascend in thehills east of the Caledonian border to be able todetermine if they are suitable differential species.Preliminary investigations made within a rathersmall area in southern Lule Lappmark shows thatLedum has an upper limit for common occurrenceat about 470-500 m. Betula verrucosa ceases atabout 450 m. The lower limit of the pre-alpineconiferous forest subregion should be drawn hereat about 450 m, and in the area investigated bothspecies prove to be good differential species. Carexglobularis, on the other hand, behaves quite differently,for it ascends the pre-alpine coniferousforest without a marked reduction in frequencyand has been observed at 680 m.Between the Scandian element on one hand andthe eastern species and part of the southern speciesActa Phytogeogr. Suec. 50