Trees for Food-A 3000 Year Record of Subarctic Plant Use
Ostlund, Lars, Bergman, Ingela, Zackrisson, Olle, Antiquity
Native peoples collected the inner bark of trees for diverse purposes across the northern hemisphere up until the late nineteenth century (see e.g. Eidlitz 1969; Erichsen-Brown 1979; Stewart 1984; Turner 1997; Zackrisson et al. 2000). Raw or processed inner bark was used primarily as a vegetable food. Inner bark was critical as a nutritional source in northern areas with long winter seasons and helped to protect from scurvy, caused by vitamin C deficiency (Urbye 1937:975-979; Ericsen-Brown 1979:8-11). Ethnographic evidence show the widespread use of different trees, primarily Pine species, across the northern hemisphere (Eidlitz 1969; Prince 2001; Kay & Swetnam 1999; Turner 1997; Sandgathe & Hayden 2003) (Figure 1).
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Ethnographic data related to native peoples, collected from the seventeenth century onwards, reveal that unique and specialised techniques were involved in the process of bark peeling and the preparation of bark for food. Compared with other plant foods, the use of the inner bark of trees has several unique characteristics. The plant food substance was taken from long-lived species (trees typically with life-spans of 400-1000 years). Bark was peeled off from part of the tree in spring when sap is running, but leaving a strip of undamaged cambium so the tree would survive. The soft nutritious inner bark was separated from the coarse outer bark and then eaten fresh, or prepared for winter storage. Such non-lethal harvesting of bark left a characteristic scar on the surviving tree, which can be precisely measured and dated by counting tree rings (Zackrisson et al. 2000). The imprint of each specific bark-peeling was left in situ, allowing the spatial pattern of resource extraction over time to be analysed in undisturbed forests. Furthermore, woody material stays more or less intact for centuries after the death of the tree in subarctic environments (Ostlund et al. 2002: 56). Woody material preserved under anaerobic conditions in peatlands or lakes may persist even longer, tip to several millennia (Eronen et al. 1999: 570-75). Bark-peeling scars therefore constitute a unique biological artefact since they cross-cut the archaeological and palacoecological records.
Bark peelings help us to understand the full scale of subsistence strategies of native peoples living in areas with long winter seasons, in which the availability of nutritious plant food was severely restricted. In general, few details are known about the exploitation of non-cultivated plants as food resources over longer historical perspectives, despite being frequently mentioned in ethnographic literature covering many regions in recent centuries. One of the main reasons for this is that the practice of plant collection has left little archaeological and palaeoecological imprint, especially in subarctic areas, resulting in disproportionate estimates of the relative contributions of plant and animal sources to the diet in non-agricultural societies of the past (Clarke 1976; Zvelebil 1994; Mithen et al. 2001).
Aim of the study
The aim of this study is to analyse and interpret the use of a specific plant-food, Scots pine inner bark, by the native Sami people in northern Sweden over a long time perspective. We also discuss how the use of inner bark may have influenced Sami subsistence strategies and mobility patterns in a subarctic landscape.
Materials and methods
We have surveyed old forests and archaeological sites in an area in northern Sweden around the town of Arjeplog (Figure 1) in the northernmost part of Sweden in search of live and subfossil trees with bark-peeling scars. The selection of the study area was based on four factors: it has a number of well-defined archaeological sites covering the time-period from the earliest documented Sami settlements to the present time; there are historical records from this specific area describing Sami bark-peeling from the seventeenth century; there is a concentration of sites with live bark-peeled trees old enough to verify the oldest written information, and there are several sites with favourable conditions for preserving woody material and subfossil pine trees close to key archaeological areas. …