was given the job of working on them. This thesis focused on the grazing quality of vegetation and was based on work done in cooperation with NR for the Geoland project.
2.2 Site Description
Location
The study area for this thesis is located in the Venabygd mountain area in cen-tral Norway. Figure 2.2 shows 2 areas (Venabygd and Sør-Fron) that have been mapped for vegetation and grazing quality by Norwegian Institute for Land Inventory (NIJOS). The Venabygd study area is defined by the NIJOS vegetation map which covers 160km2. The area lies in Ringebu Community in Oppland county.
Figure 2.3 shows a more detailed map of the study area. The Sør-Fron commu-nity borders the western section while the northern border is defined by the state highway (RV) nr.27. The Eastern border of the area follows the valley and river south to Jønnhalt. The southern border of the area goes from Jønnhalt along the road to Venabygd. The highest point is Nødre Bølhøgda in the north at 1356m a.s.l. The town Venabygd, located at the southern end of the study area, is located at61◦34′60N and10◦3′0E, at an elevation of 579m (Bryn and Rekdal, 2002).
The Venabygd site area is used to analyse the possibility of mapping grazing qual-ity with Landsat imagery. The neighbouring site of Sør-Fron (seen in figure 2.2) was intended as a potential test sight for any classification procedures developed from the Venabygd site. The areas have very similar vegetation types and are on opposite sides of the valley to each other.
Vegetation
Besides natural environmental factors such as topography, climate and geology, the history impacts in terms of agricultural land use, animal husbandry and also natural disturbances (avalanches, rockfall, mudslides) play a major role in the spatial distribution of vegetation types (Hoersch et al., 2002). The vegetation dis-tribution changes significantly in the Venabygd area from down the valley to up above the tree line in the mountains. This change in height leads to changes in climate of which temperature is the most influential factor for vegetation distri-bution. Figure 2.4 shows a list of the vegetation types in different height zones in the area. The tree line lies at approximately1050ma.s.l and is dominated by mountain birch a tree species that because of rehabilitation is establishing itself in large areas around Venabu and Flaksjøen. Around950ma.s.lthe dominance of coniferous trees becomes more noticeable where as lower down the spruce trees
Figure 2.2: An outline map of southern Norway. The study area Venabygd is selected in red.
Venabygd is the town located at the bottom of the study area (shown in fig 2.3). It has the location61◦34′60Nand10◦3′0E. On the other side of the valley is Sør-Fron an area which has also been mapped for vegetation and grazing quality by NIJOS. Co-ordinate system unknown.
2.2 Site Description 11
Figure 2.3: Overview map of the Venabygd study area. The study area covers 160km2. The council area is part of the Ringebu Community and Oppland county. The Sør-Fron community borders the western section of the area while the northern border is defined by the state highway (RV) nr.27. The Eastern border of the area follows the valley and river south to Jønnhalt. The southern border of the area goes from Jønnhalt along the road to Venabygd. Venabygd is located at61◦34′60N and10◦3′0E, at an elevation of 579m. The highest point is Nødre Bølhøgda in the north at 1356m a.s.l The map shows the lakes, river network, road and tractor network, and some of the main place names. The contour lines are 20m. Co-ordinate system: UTM zone32, EUREF89 / WGS84.
dominate the forested areas (Bryn and Rekdal, 2002).
Figure 2.4: Vegetation zones in the Venabygd area divided according to elevation. Because elevation governs the climate and especially temperature it can be used as a main feature in dividing the vegetation into zones. Copied and modified from Bryn and Rekdal (2002).
Figure 2.5 shows an image of the Venabygd area and the coverage of the different grazing qualities in the area, defined by NIJOS. The Venabygd mountain area has 92km2 of productive sheep land and 107km2 of productive cattle grazing land.
These productive areas are only productive from spring to autumn. Venabygd mountain has a large height variation but there is relatively little snowbed (snøleie) vegetation, this leads to a drop in grazing quality out over August. If grazing has been significant this can encourage renewed growth in the vegetation which can extend the grazing period further past August. The grazing impact is quite high in the areas north of Nødre Bølhøgda. In the summer farm and forest areas the grazing impact is middle, and on the valley sides it’s low (Bryn and Rekdal, 2002).
Climate
Near the state highway at the top of the Venabygd mountain area the Norwegian meteorological institute has measured different climatic factors since 1980. The measurements show that the region has a typical inland climate with low winter temperatures and high summer temperatures in respect to the height above sea level. The mapped area has an elevation from 330 to 1365ma.s.l. January has the lowest average temperature of−9.7◦Cand July the highest with an average of
2.2 Site Description 13
Figure 2.5: This map shows the grazing quality distribution over the study area, Venabygd.
The grazing quality types are defined by NIJOS. Good quality grazing dominates the area, followed by Less Good and then smaller areas of Very Good. Coordinate system: UTM zone 33, WGS84.
+10.4◦C. The average annual temperature is −0.3◦C. The average annual pre-cipitation is660mm. The rainfall pattern is similar to that of temperature meaning that the lowest rainfall occurs in the winter and the highest rainfall in the summer (Bryn and Rekdal, 2002).
Geology
Nutrient poor sandstone and quartzite dominate the geology, and the area has varying moraine sediment coverage as well as bare rock surfaces. Outlined in the geology map ”Lillehammer” in scale 1 : 250,000 the area is dominated by sliding slate made of feldspar sandstone and quartzite from the late Cambrian period (Siedlicka et al., 1987). This is a highly erodible rock type that gives little access to nutrients. However, growth of vegetation occurs in areas that have good access to water (Bryn and Rekdal, 2002).