Conservation

Conservation

One of the most important measures for conservation of the rock art is reducing traffic on or near the figures. But the museum has introduced other measures to improve conditions for the World Heritage.

Even though the rock carvings in Alta have survived for up to 7000 years, there is no guarantee they will last forever. Over time, everything wears down, even rocks and stones, and therefore we have to do all we can to prevent or slow down that process. The rock surfaces where the rock carvings are found are broken down in three ways:  by chemical corrosion, biological erosion, and mechanical destruction. Chemical and biological erosion relate to the fact that flowers, trees, grass, lichen etc. grow on rock surfaces, and their roots can destroy the rocks. Moreover, a number of organisms, such as moss and lichen, can create an acidic environment (high pH) which makes the surfaces even more porous and more susceptible to damage. Mechanical erosion or destruction concerns the way the rock surface is destroyed when it is exposed to external forces, such as when people trample on the rock. External forces like these can create an environment which causes the rock surface to crack and be destroyed.

So, what can we do to prevent this? Well, one of the things we have done is to organise activity at Hjemmeluft in such a way that is possible to stroll along paths around the rock carvings without exposing them to mechanical erosion. By keeping people off the rock surfaces we save the sites from severe stress. In addition, we use much time and effort in weeding and cutting to prevent the growth of vegetation. We treat surfaces with ethanol so that vegetation (lichen) which has become ingrained in the rock loosens its grip and disappears. By removing the lichen we ensure that the pH-value of the rock is at its most favourable level. We also use brooms to clear away leaves, pine needles and litter. This blocks the decomposition processes which would otherwise create a more acidic environment.

We work constantly on spreading information about the rock art. We do this by extensive registration of the areas, the sites, and the figures. Photography is the most used method, and from the photos we make tracings. This process is to rock art what a map is to the terrain; it is a drawing of the figures placed in relation to each other, just as they are placed in reality. Another product we make is photo-mosaics. This is a series of pictures put together in such a way as to create a 3-D model.  We then compress the 3-D model to a 2-D model so that we end up with a picture of the whole site with a resolution which enables us to see every single figure, irrespective of how large the site is. We also make maps of the area based on aerial and satellite photography.