Rapid Assessment Reference Condition Model

Hemlock and white pine have wide ecological amplitudes, occurring with wetland conifers in poorly-drained landforms and with mesophilic northern hardwoods in marginal upland landforms. White pine and hemlock become dominant within mixed forests in upland ice-contact and glacial lakebed landforms of intermediate soil fertility. These landscape ecosystems typically have low proportions of sugar maple and associated mesophilic deciduous species due to limited soil nutrient availability or moisture holding capacity. Species adapted to frequent disturbance (e.g., jack pine, aspen) occur in low proportions. Vegetation Description In the mid-1800s, there were 2.2 million acres of white pine-hemlock ecosystems within the 10.6 million acres of forestlands in northern Lower Michigan (Province 212; Cleland et al. 2004, ongoing R-9/SRS/MTU study). Based on analysis of GLO line tree observations, white pine–hemlock communities were dominated by “pine ” recorded to the genus level, followed by hemlock, white pine, red pine, and beech. It is likely much of the undifferentiated pine was white pine given the large diameters of this class (mean of 19.3 inches). Pine and hemlock comprised 62 % of GLO line trees, mesophilic sugar maple 3%, and early successional oak, white birch, and aspen 10%. In the mid-1800s, there were 3.2 million acres of white pine-hemlock-birch ecosystems within the 17.