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The North-East CornerBy ERIK JULIN and SVANTE PEKKARITERRESTRIAL VEGETATION AND FLORABy Erik JulinPhysiographyThe north-east corner of Sweden, which consists ofthe two parishes Nedertornea and Nederkalix, includesa wide archipelago and a part of the mainlandentirely below the highest Post-glacial coastline. This country emerged only in a comparativelylate period from the Bothnian Bay. The land areais still increasing along the coast and among theislands, partly through the land upheaval which isestimated at 84 cm per century and partly throughthe sediment transport by the rivers, which producesnew land nearly as effectively. In these wayson an average about one and a half metre of newland is formed per century. The present lowlandthus only rose from the sea one or two millenniaago and is still emerging.The old bedrock underlying the lowland waseroded at the end of the Pre-Cambrian era until itformed a peneplane with much the same sculptureas to-day. However, the last ice sheet of the Quaternaryhas deposited a cover of drift on top of thebedrock. It is almost completely unbroken andexposed rock is very rare. In the broad river valleysthe morainic till is covered by fluvial sediments.The vegetationFORESTS AN WOODLAND.-The most importantterrestrial types of vegetation as far as area isconcerned are forests and mires. Owing to the smallgradient impeding the run-off of water, broadtransitions occur between forests on dry land andmires. These transitory areas are mainly developedas swampy woodland. Large parts of the drift areasbetween the river valleys and in the interior of thelarge islands are covered by conifer forest. Thisforest was badly treated in former times, partly asa result of deficiencies in the laws regarding landuse. Devastating cutting of the best timber andneglect of sylviculture has had the result thatspruce (Picea abies, mainly ssp. europaea but also· ssp. obovata) of poor stature has come to dominancein uneven stands on types of soil where pine (Pinus .silvestris) would be better adapted.Pinewoods occur mainly in the western parts ofthe district, on the Nikkala peninsula and on a fewof the islands including Seskaro, Seskarfur6, Tornefur6and Sandskar. In the glaci-fluvial area ofcoarse sediments known as Bredviksheden and onthe islands it is developed as pine-lichen forest;elsewhere mainly as pine- V acciniuk forest with abottom layer of mosses. As mentioned spruce forestshave an unnaturally wide distribution andshow evident vestiges of the former misuse. Theynearly always show a small increment and do notreact favourably to further thinnings. On moistersoils birch (Betula pubescens) occurs scattered inthe spruce forest. This species of birch may formalmost pure stands on drained areas that have notbeen cultivated. Near the farms enclosures ofgrazed forest contain a mixed forest with birches,· spruce and occasionally other trees even on drysoils.The mentioned types of forest are more or lessinfluenced by human activity. Almost virgin areSorbus aucuparia woods of the archipelago and aquite extensive forest of Populus tremula on theisland of Sandskar.The islands of the arch1pelago are partly formedfrom low hillocks of glacial drift, carrying deciduouswoods mainly consisting of Alnus incana and BetulaActa Phytogeogr. Suec. 50