Our objective was to assess the relative rarity and representation within protected areas of Standard Forest Units (SFUs) in northeastern Ontario by applying the concepts of geographic range, habitat specificity, and local population size. SFUs are stand type classifications, routinely employed by forest managers, based on tree composition, disturbance history, and prescribed silvicultural system. We identified several SFUs as rare because of a narrow distribution, association with only one landform type, or lack of at least one stand larger than an ecoregion-specific threshold. In the Boreal forest, rare SFUs comprised stands dominated by eastern hemlock ( Tsuga canadensis (L.) Carrière), red oak ( Quercus rubra L.), yellow birch ( Betula alleghaniensis Britt.), or eastern white-cedar ( Thuja occidentalis L.). Rare SFUs also included eastern white pine ( Pinus strobus L.) and (or) red pine ( Pinus resinosa Ait.) leading stands managed by shelterwood or seed tree silviculture as well as low-lying deciduous stands and selection-managed stands of shade-tolerant species. In the Great Lakes – St. Lawrence forest, rare SFUs were yellow birch stands, stands dominated by conifer species abundant in the Boreal, and shelterwood-managed hardwood stands. Several rare SFUs had <12% of their total area in protection, i.e., stands dominated by eastern white pine, yellow birch, eastern white pine – red oak, or eastern white-cedar. These rare stand types require increased protection in reserves and tailored silvicultural practices to maintain their probability of persistence.
