Abstract
Deer yards are wintering areas used by white-tailed deer in the northern part of their range. In northern Michigan, deer yards typically consist of extensive stands of cedardominated (Thuja occidentalis) or mixed conifer swamps where thick evergreen overstories provide shelter from winter conditions. Forest and wildlife management in and around cedardominated swamps of the upper Great Lakes have created a nearly optimal interspersion of early-seral summer range and mature conifer winter range. For a variety of reasons which include favorable habitat changes, deer populations are today larger than those of presettlement conditions. We used General Land Office survey records from the 1840s to compare presettlement forest composition with present-day forest composition in two important deer yarding areas in Michigan's Upper Peninsula. Except for tamarack (Larix laricina), woody plant species that are unpalatable to deer or tolerant of browsing have increased. Species that are palatable and intolerant of browsing have decreased. Ages of extant mature cedars indicate establishment during a period of low deer populations in Michigan. Change in forest composition has many causes, but deer populations encouraged by forest and wildlife management may contribute to a changing ecology in northern Michigan's conifer swamp communities, and may change the structure of plant communities in areas where deer use is concentrated.