The changing structure and tree composition in the traditionally grazed forests in the parish of Stenbrohult, southern Sweden
Slash-and-burn cultivation (each treated plot usually 1600 – 2100 m2) occurred annually on all three farms in the 1790ies, but it is unknown when this land use ceased on these farms. The first detailed forest management plan is from 1878, but pollen analyses reveal a decrease of deciduous trees and an opening up of the forest until about 1850. The utmark was about 67 % of the farms total area around 1880. At this time the grazed forest was very heterogeneous with many small and a few larger open mires. Total proportion of mire (open fen and bog) was 15 – 36 % of the utmark on the three farms. There were many other openings in the forests, including a few due to forest cuttings (about 0.1–0.5 ha each year on a farm). The old forest planned for cutting at that time was dominated by pine Pinus and spruce Picea, but sometimes with much birches Betula (Table 2). However, most of the utmark was an open birch-dominated forest (tree volumes usually 20 – 80 cubic meter per ha). Later these birch trees were cut, to be used as firewood on the farms, which transformed the older forest to a dense coniferous forest dominated by spruce. This old forest was recently cut (mainly in the 1980ies), the small mires were drained and spruce was planted. The dense regeneration of birches, oaks, aspen and beeches on the clearcuts have been cleared around the planted spruces. Thus, during the last 150 years there has been a drastic transformation due to man from an open mixed birch-dominated forest grazed mainly by cattle to a dense spruce-dominated forest without domestic animals. The documented forest management on these farms refute the climate and spruce immigration hypotheses as explanations for the recent changing tree species composition in southern Sweden. Spruce has been actively promoted by man and his domestic animals more than 100 years in this area and I suggest that this is a general pattern in large regions.
- land use
- ISSN: 0039-646X