rnen and Renbergstjärnen. A comparison of the maps from 1805 and 1880 shows that the meadow area increased from 0.3 to 7.9 ha around Bergtjärnen and from 0.3 to 4.7 ha around Renbergstjärnen. The map from 1805 does not contain any data on unused mires, so we do not know whether the increased meadow areas were gained from forest or from mire. If we assume the latter, the conclusion would be that about 12 ha of mires, or 4%, were converted into meadows through artificial flooding. Later, damming was mainly adapted to the needs of timber floating. The dam at Renbergstjärnen was abandoned in 1935 and the one at Bergtjärnen in 1967, when timber floating ceased (Archives of Umeå flottningsförening).
As previously mentioned, the mire meadow Klockarmoren is said to have been illegally reclaimed already in the early 1800s (Anon., 2015). It eventually became arable land, and is one of the very few former mire meadows that is currently cultivated. There is a central ditch through the field, and possibly also covered ditches. However, we do not know what measures were taken to reclaim the area during the 1800s; it was still classified as a mire meadow in 1880, with irregular shape, and does not appear in any official documentation on ditching projects. Another early reclamation project was connected to a new settlement, Koverberget, which was established in 1886 on land belonging to Abborrtjärn village, but which is now abandoned (Larsson, 1988). The DTM reveals that there are ditches, probably dug around that time, along the former fields of the settlement, and most of these ditches concern areas that were in 1880 classified as ‘mire’. This small-scale, private initiative was followed around 1900 by a large state-financed project to prevent frost damage in Abborrtjärn and several neighboring villages (Väg- och vattenbyggnadsstyrelsen, 1872–1910). The cadastral map from 1912 shows a large central ditch through Vorrmyran (Figure 2d), which was probably a result of that project. In 1915, another ditching plan was established for Vorrmyran (Figure 2e), and at some point before 1963 connecting ditches were dug along the narrow fields that were created (Figure 2f). In 1919, a ditch plan to prevent frost damage was made for another mire, Hukladumyran. Although the plan was realized, it was never followed by cultivation. The analysis of the aerial photos from 1963 shows that these ditching projects, together with the abovementioned reclamation of Klockarmoren, led to the creation of about 9 ha of arable land from 6 ha of mire meadows and 3 ha of unused mires, corresponding to about 3% of the total mire area.
The mires chosen for reclamation were among the more productive ones, especially the ones that were ultimately cultivated. Klockarmoren had probably already been concerned by some measures before 1880, when the meadows of the site were classified as best grades, 1–1.2. The largest well-known ditching project, Vorrmyran, drained mire meadows with grades 1.5–8 and formerly unused mires with grades 10–20. At Koverberget, the reclamation transformed two formerly unused mires of grade 12. By contrast, the ditching of Hukladumyran, which never lead to cultivation, drained mire meadows with grades 4–16 and unused mires with grades 50–100.
The analysis of the DTM shows that there are currently almost 39 km of ditches in the study area, road ditches excluded. About 40%, or about 15 km, run through the total mire area as defined from the 1880 map. Most of the ditches affecting mires, about two thirds, were dug to enhance wood production, whereas the rest were for agricultural purposes.
Most ditches dug for agriculture are well documented and can be dated almost to the year, but we have not been able to date the ditches dug for silvicultural reasons. Forestry maps of Sandviks Ångsågs AB from the region generally show both ditches and the year they were dug, but on the maps covering Abborrtjärn, drawn in 1941, ditches are absent. We therefore assume that forest ditching in the study area generally took place after that year.
The buffer analysis sh