Putting down roots: the emergence of wild plant food production on the Canadian plateau
Date
2013-04-12
Authors
Peacock, Sandra Leslie
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Abstract
This research traces the emergence of wild plant food production during the Late
Prehistoric Period (4500 to 200 BP) on the Canadian Plateau. It builds upon
ecological-evolutionary perspectives offered by theories of people-plant interactions and
models of plant food production. From this, it derives a general model of wild plant food
production outlining the components of such systems, the conditions favouring their
development, and the consequences and correlates of these activities. This general
model is expanded and made specific to the Canadian Plateau through ethnographic,
ethnobotanical, ecological and archaeological evidence for root resource use by the
Secwepemc (Shuswap) and other Interior Salish peoples. The implications of these
findings for reconstructions of Late Prehistoric culture change are discussed.
The study has two components. It begins by demonstrating that historically, the
Interior Salish peoples were not plant collectors, "adapting to" the environment, but
plant food producers who "domesticated" the landscapes of the region. Ethnobotanical
evidence indicates the Secwepemc managed. processed and stored a variety of plant
resources to increase their productivity and availability. These actions ensured surpluses
for overwintering, reducing the threat of recurrent seasonal resource stress.
Root foods were particularly important. At least 20 species were regularly
harvested and stored. Practices associated with harvesting were essentially horticultural
and acted at the species, population and landscape levels to increase the density and
distribution of targeted species. The productivity of root resources was also increased
through processing in earth ovens. An experimental reconstruction of an Interior Salish
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earth oven found pitcooking increased the energy value of balsamroot (Balsamorhiza
sagittata), a former root staple, by 250 percent. Balsamroot contains inulin, a complex
carbohydrate indigestible in its raw form.
The second component of this study traces the beginnings of these wild plant
food production systems through the archaeology of earth ovens. The discussion begins
with Komkanetkwa, a traditional root gathering ground of the SeC\\<"epemc located near
Kamloops, British Columbia, where investigations identified the remains of 170 earth
ovens, II of which were excavated. Similar data from four additional root processing
locales, including the Upper Hat Creek Valley, Oregon Jack Creek and Potato Mountain
on the Canadian Plateau and the Calispell Valley on the Columbia Plateau, are also
presented.
Analysis of site types and distributions, the structure and content of earth ovens
and radiocarbon age estimates associated with them reveals root food production began
approximately 3100 years ago on the Canadian Plateau. The broad pattern of root
resource use, consistent with ethnographic expectations, is well-developed after 2500 BP
and persists until historic times. Radiocarbon age estimates (n=30) indicate a peak in
activity developing between 2250 and 1750 BP.
A review of the paleoenvironmental and culture-historical context identified the
conditions, consequences and correlates of these processes. The catalyst for the
development of these strategies was a dramatic decline in temperatures approximately
3900 years ago. This ushered in a 2000-year period recognized as the coldest and
wettest stage of the Holocene, one characterized by long, cold winters. Under these
conditions, wild plant food production represents a risk reduction strategy developed by peoples of the Canadian Plaeeau to cope with the uncertainty of seasohnal and annual environmental variation and prolonged periods of resource scarcity. In sum, earth ovens are the archaeological manifestations of fundamental shift in the process of people-plant interactions -- the transition fro foraging to wild plant food production which occurred on the Canadian Plateau at least 3100 years ago. This transition represents the adoption of strategies designed to ensure the productivity and availability of plant resources, particularly storable carbohydrates derived from roots, for overwintering.
Description
Keywords
agriculture, prehistoric, wild plants, plateaus, prehistoric peoples