| In this study, the General Land Office (GLO) survey notes (1840-1856), current land cover generated from Landsat TM Imagery (1991), and Forest Inventory and Analysis plots (1991-1992, US Forest Services were used to reconstruct the presettlement forest and examine changes in forests of the Luce District in the eastern Upper Peninsula of Michigan over the past 150 years. Also, a spatially explicit model in a Geographic Information System (GIS) was developed to investigate the impacts of stand-replacing disturbances on landscape patterns.; Interpretation of the GLO notes in the Luce District demonstrated that the presettlement landscape was a mixed conifer matrix (39% of total area), interspersed primarily with northern hardwoods (29%), wetlands (14%), fire-susceptible pinelands (13%), and other cover types (5%). Boreal forest species comprised 66% of the total witness trees in the Luce District. The GLO surveyors recorded 104 fires and 126 windthrows which accounted for 3.1% and 2.8% of the total length of the surveyed lines. Calculated rotation periods for the entire Luce District were 480 years for fire and 541 years for windthrow, and 7.5%, 24.4%, and 68.1% of the presettlement forest were in the stand initiation, stem exclusion, and old forest stages (including both understory reinitiation and old-growth stages), respectively.; Notable changes in species composition over the last 150 years are characterized by the increase of red maple (Acer rubrum; +14%) and the decline of tamarack (Larix laricina; {dollar}-{dollar}11%), hemlock (Tsuga canadensis; {dollar}-{dollar}7%), white pine (Pinus strobus; {dollar}-{dollar}6%), and beech (Fagus grandifolia; {dollar}-{dollar}5%).; Simulation of a homogeneous 100 * 100 pixel landscape with an arbitrary 500 year rotation period indicates that landscape composition (proportion of the landscape area allocated to various stages of stand development) is stable, regardless of contagion, variation in annual disturbed area, or hazard (i.e., the probability distribution of disturbance of a given stand in relation to stand age). Variation in the disturbed area generates a highly dynamic landscape in terms of proportion of stands in different stages of development, especially in the earlier stages of succession. Disturbance hazard basically re-allocates portions of the landscape into various successional stages, and contagion produces fewer patches with larger maximum and average patch size in the earlier stages of stand development. (Abstract shortened by UMI.)... |
