Pristine forest landscapes as ecological references

Northern boreal forests that display no signs of forestry or agriculture in the past are often regarded as intact, pristine forests. Yet, humans have inhabited these environments for millennia and developed a variety of economic strategies for their subsistence. Generally, these forms of land use have been regarded as minor disturbances, and have thus frequently been neglected in ecological studies. Despite the increased recognition of the importance of past land use in other forest landscapes, the land use effects in northerly remote forests remain unclear. In this thesis the influence of human land use on forest structure, composition and biodiversity (dead wood and wood-inhabiting fungi) during the last 1 000 years was studied in three Scots pine forests in northern Sweden. For this purpose I used an interdisciplinary approach, combining field studies on present forest characteristics with long-term records such as archaeological remains and biological archives, and short-term records such as historical documents. My results show that long-term, low-intensity land use can substantially influence forest structure and composition and that land use legacies can reverberate through the ecosystem for many centuries. This implies that forests in remote and inaccessible areas with no recent management cannot be indiscriminately used to represent ‘pristine’ reference conditions. The results also show that to understand the overall magnitude and complexity of the relationship between humans and the land, all forms of human activities that may have occurred within the studied space should be considered. Furthermore, different patterns and gradients of past land use; varying in space, time and intensity across landscapes, create ‘layers’ of land use. The result is a matrix in which some areas have been heavily used for extensive periods of time whereas other parts may have practically escaped human exploitation. To detect and interpret anthropogenic disturbance in northern forest ecosystems a clear strategy for choosing relevant methods and applying them in the right order should be adopted. Then, possibly pristine forests can be evaluated as reference areas for addressing scientific research questions and conservation management