Jord- och skogsbruk
Här ska så småningom en beskrivning av markanvändningen inom Emåns avrinningsområde finnas. Tyvärr har vi inte haft tid att skriva denna text ännu. Tills vidare ges nedan en kort beskrivning av markanvändningen inom avrinningsområdet på engelska, utdrag från boken "Water: local planning and management" inom projektet ENMaR som Emåförbundet deltog i under 2005-2007 (se www.enmar.org). Boken i sin helhet kan beställas av oss mot portokostnad men det går också bra att hämta ett gratis ex på vårt kontor i Vetlanda.
Forestry (skogsbruk)
The land use in the Emån basin is dominated by forests land, approximately 335 000 ha. This is 75% of the land area of which 65% are referred as productive forest and the remaining 12% as impediment (annual growth less than 1 m³/ha/yr).
All sub-basins are covered by forests with more than 65%, 76% on average and the most afforested sub-basins are those in the middle part of the basin, on a north-south transect. Sub-basins with the lowest share of forest (around 65%) are situated in the Emån flood valley, hence the most intense agricultural areas.
The most common tree species in the Emån basin are spruce, pine and birch. Coniferous forests covers approximately 71% of the whole basin (~ 320 000 ha) whereas broadleaved forests are sparse and covers about 4% of the basin (17 800 ha). The most common broadleaved tree species are birch, common alder, aspen and mountain ash in the higher parts of the basin. The lower parts in southwest have a greater dominance of selected broadleaved forest species as oak, beech, elm, Norway maple and ash.
There are yet no exact figures of the standing volume by tree species in the Emån basin. The total standing volume in Sweden comprises approximately 3 000 million m3, of which the Emån basin comprises less than 1% - i.e. approximately 24,3 million m3. Of these, approx. 95 % are coniferous forest and about 5% are broadleaved forests.
The annual gross felling in Sweden was 85 million m³ during 2004. The average area of fellings was 4,4 ha, according to statistic models by the national board of forestry. The annual gross felling within the Emån basin has not yet been calculated. A rough estimate however, would be approximately between 600 000 and 700 000 m³ gross felling per year.
Agriculture (jordbruk)
The agricultural land in River Em catchment is in the first place situated in the floodplains and adjacent areas of river Em and its largest tributaries. This is mainly because of the more fertile soil, a suitable topography, good supply of water for irrigation and overall good climate conditions as referred to temperature, moisture and drainage. The most intense agricultural areas are situated along River Em`s lower parts, within the municipalities of Hultsfred, Högsby, Mönsterås and Oskarshamn. In these areas, large floodplain plateaus were created during the last glaciation which has created the best conditions for agriculture in the catchment.
The annual precipitiation in river Em catchment area is on average 600 mm, which is close to the annual mean in Sweden as a whole. There is however a precipitation gradient across the catchment. The northwest part, referred as the south Swedish highland, has got a mean annual precipitation of approx. 700 mm, whereas the southeast part is dryer with around 500 mm/year on average
The air temperature varies greatly during the year, from mean minimum of -6,5° C during January and February, to mean maximum of +20,5° C during july and august. The highest and lowest temperatures respectively are often around +28-30° C and -26-28° C.
Natural geography
The bedrock within River Em catchment is principally made of igneous rocks such as granite. These are very resistant to erosion which generally has lead to acid and poor soils. But there are also areas with metamorphic and sedimentary rock types, e.g. amphibolite, sandstone and greenstone, which are more erodible and give rise to more alkaline and fertile soils. These areas are mainly situated in the middle of the catchment, from west to east.
The soil structure within the catchment is vastly dominated by moraine and its characteristic formations due to the last deglaciation some 10 000 years ago. The catchment is distinguished by impressive glacifluvial remnants, with more sandy and silty soils in the flood plains. There are also small areas with peat soil distributed all over the catchment.
Distribution of territorial lands
The land use in River Em Catchment is dominated by forests (72%) and the agricultural regions represent about 15% or just over 57 000 hectares, see figure 2 below. About 2/3 of the arable land is situated in the county of Jönköping (central and western part of the catchment) and the remaining 1/3 in the county of Kalmar (eastern part of the catchment. In all, there were about 38 500 ha of arable land and 18 500 ha pasture in the catchment during 1999 (Eman Union 1999).
The agricultural area is most dominant in the sub catchments number 2, 16, 15 and 4 and divided by municipalities the most dominant area is represented in Vetlanda, Eksjö and Hultsfred municipalities.
The dominating crop in the whole catchment is pasture for haymaking, beside the 1/3 of the total agricultural area that represents pasture for animals (se figure 3). The remaining crops of importance are spring- and autumn sawn grain which constitute 17% and 1% respectively.