A Study of Yellow Birch (Betula lutea) in the Bogs of Itasca Park, Minnesota

Abstract

The occurrence of an organism along the margins of its range of distribution often affords interesting contrasts to its status in the central portion of its range. The present study, which was carried out during the summer of 1957 on three small stands of yellow birch (Betula lutea) near the Lake Itasca Forestry and Biological Station, provides data indicating a highly circumscribed habitat in vivid contrast to occurrence within its main area of distribution. In addition to this, the age distribution of the stands, which appears to be the result of pressures from herbivores, is discussed. The normal habitat of yellow birch is commonly referred to as rich woods (Fernald, 1950) or moist woods (Gleason, 1952). Thus, Potzger (1946), after finding this species in the upland woods of northern Wisconsin, assumed it to be an element of the upland forest in Minnesota as well. However, Rosendahl (1955) clearly states that it is associated with black ash (Fraxinus nigra) and tamarack (Larix laricina) in boggy situations in Minnesota. Elsewhere at the margin of its range, yellow birch has been found to occur only in bogs (Watts, 1957).