A comparison of historical and current forest cover in selected areas of the Great Lakes–St. Lawrence Forest of central Ontario

Abstract

Crown survey notes from the late 1800s were used to reconstruct forest cover at that time in four forest management units in central Ontario, Canada. Historic forest cover was then compared to forest cover in 1990 based on Forest Resources Inventory (FRI) maps. Regional results indicate that the proportions of maple (Acer spp.) in the forest increased by 12.5%, while balsam fir (Abies balsamea) declined by 3.5%, hemlock (Tsuga canadensis) by 2.3% and other conifers (larch (Larix laricina) and cedar (Thuja occidentalis)) by 2.1%. The frequency of occurrence of maple, ash (Fraxinus spp.), yellow birch (Betula alleghaniensis), poplar (Populus spp.) and spruce (Picea spp.) also increased while white birch (Betula papyrifera), hemlock and other hardwoods (e.g., oak (Quercus spp.), basswood (Tilia americana), beech (Fagus grandifolia), elm (Ulmus spp.), ironwood (Ostrya virginiana) and black cherry (Prunus serotina Ehrh.)) declined. The region-wide proportional increase in maple is likely due to timber harvest techniques such as selective logging, effective fire suppression and the ecology of the maple species. Crown survey notes have been a useful tool in reconstructing presettlement forest cover. Survey notes can easily be obtained and used by forest managers and planners to understand presettlement conditions of this forest. Managers can achieve zero net loss of forest types in relation to the presettlement condition by using appropriate silvicultural practices to reduce the proportion of maple. Key words: Crown Survey records, presettlement forest, Great Lakes–St. Lawrence Forest, working group, frequency of occurrence