Human impact on forests in early twentieth century Finland

Context In northern Europe, changes in forest ecosystem structures are commonly attributed to the ubiquitous impact of modern forestry. However, the starting point for modern forestry was not a pristine forest, but landscapes influenced for centuries by diverse human activities. Objectives Our aims were to (1) describe spatial patterns of forest structure and species compositions over large scales in 1920s Finland, and to (2) analyze how these characteristics were influenced by human population and past land-uses. Methods We mapped ca. 3000 systematic sample plots measured in the first Finnish National Forest Inventory (1921–1924) and produced a series of maps of large-scale variation in forest characteristics in upland forests. We analyzed forest age and size structures, and species compositions relative to human population and land-use data. Results We found strong geographical and regional gradients in forest age and size structures, and tree species composition. Depending on the variable, these characteristics were at the stand-level best explained by human population density, reflecting the long history of various forest uses. Tree species composition was clearly associated with site productivity, but also with the history of slash-and-burn agriculture and forest grazing. Conclusions Forest landscapes in the early twentieth century Finland exhibited a strong human fingerprint, visible as the abundance of young forests in populated areas, while in remote areas forest characteristics typical of natural forests prevailed. These gradients in human impact a century ago are still reflected as legacies in forest structure, a situation that needs consideration in management and restoration.