Historical changes in the forests of the Luce District of the Upper Peninsula of Michigan

General Land Office (CLO) survey notes (1840-1856), current land col er gen erated ii from Landsat TM Imagery (1991) and the Forest Inventory and Analy sis plots (1991-1992, US Forest Service) were used to examine changes in fo rests of the Luce District in Upper Michigan over the past 150 y. Historica l changes in two subdistricts, Grand Marais and Seney: were also analyzed. Interpretation of GLO notes showed that the presettlement landscape was a m ixed conifer matrix (39% of total area), interspersed primarily with northe rn hardwoods (29%), wetlands: (14%) and fire-susceptible pinelands (13%). E stimates of pre-European settlement stand density ranged from 81 trees/ha i n open lands to 408 trees/ ha in northern white cedar stands (Thuja occiden talis), and estimates of basal area ranged from 3.5 m(2/)ha in wetlands to 27.7 m(2)/ha in mixed hardwood/conifer forests. Notable changes in species composition over the last 150 y are the increase of red maple (Acer rubrum: + 14%) and the decline of tamarack (Larix laricina: -11%), hemlock (Tsuga canadensis; -7%), white pine (Pinus strobus, -6%), beech (Larix laricina, - 11%) and yellow birch (Betula alleghaniensis, -5%). Contrasts between the t wo subdistricts, Grand Marais and Seney reflect the influence of the integr ation of climate, physiography and disturbance regime. Overall presettlemen t vs, present-day tree diameter distributions differed between the two time periods. Differences in the diameter distributions among individual tree s pecies are related to their growth rates and life expectancies. The diamete r distributions of short-lived species are similar between the two time per iods. Most species hale diameter distributions with more small trees toda, than in presettlement forests, especially long-lived taxa such as hemlock a nd white pine.