Final Report to the National Park Service on Forest and Disturbance History of the Apostle Islands

A management program of the forest vegetation on the Apostle Islands National Lakeshore not only requires an assessment of the present forests but also knowledge of the forest composition prior to European settlement, the frequency of forest disturbance before logging began, and the changes or trends occurring in the vegetation prior to settlement. Descriptions or inventories of the present forests are already available for many of the Apostle Islands (Beals and Cottam, 1960; Anderson et al., 1978; Coffin, 1979; Hildebrant, 1978; Jefferson, 1979; Larson, 1975; Roth 1898), but no detailed and well-dated paleoecological studies of forest vegetation and fire history of the past few thousand years currently exist. Some early studies by Wilson (1935, 1938) on the Bayfield peninsula and the islands were not dated, lacked stratigraphic detail, or only represented some of the earlier periods of vegetation history following deglaciation. Some question regarding presettlement forest composition can be obtained by identifying old stumps that still remain from the time of cutting (personal observations) or by studying logging histories and cover-type maps made from land survey records (Rakestraw et al., 1979; Finley, 1976; Office files, Apostle Islands National Lakeshore). Unfortunately, on can not tell from such records whether white pine or other dominant or commercially valuable trees were increasing or decreasing in abundance at the time of initial logging. The paleoecological work described in this report examines the recent and past fire history of Stockton Island and the composition and the changes occurring in the presettlement forests on Stockton Island, Bear Island, and the Bayfield peninsula. Pollen and charcoal analysis of lake and bog sediments and tree-ring analysis of fire-scarred living trees and charred stumps provide the basis for reconstructing former environmental conditions. The record of fire history from Stockton Island will be important for forest management since periodic fires have played a dominant role in shaping the composition of the hardwood-conifer forests in Minnesota and other parts of Wisconsin (Maissurow, 1935; Ahlgren and Ahlgren, 1969; Heinselman, 1973; Swain, 1973, 1978, 1980).