The jack pine resource in Michigan: An assessment of volume, growth, mortality, and coarse woody debris

Jack pine (Pinus banksiana Lambert.) is economically and ecologically important in the Lake States region and throughout much of Canada. The current state of the jack pine resource was assessed in six regions in Michigan and one region in Wisconsin by quantifying standing live and dead volume, mortality, top-kill, annual radial growth patterns, and coarse woody debris volume in one 0.01 ha circular plot per stand. Overall, live and dead volume was higher on state land in the western Upper Peninsula of Michigan than in the other six surveyed regions averaging 448.5 m3/ha live volume and 68.4 m3/ha dead volume. Accumulation of coarse woody debris volume was highest in the Ottawa National Forest (64.2 m 3/ha) and the Huron-Manistee National Forest (60.1 m3/ha). Stand age had the most consistent relationship with all variables except radial growth rates across all regions. Stands 50+ yrs old generally had higher levels of standing volume, more mortality, and higher accumulation of coarse woody debris volume than younger stands. Under-stocked stands had less volume, mortality, and lower amounts of coarse woody debris volume than well-stocked or over-stocked stands. Patterns among standing volume, mortality, radial growth rates, and site index were unclear within regions. Among crown classes, mortality was generally higher in intermediate and suppressed trees than dominant trees. However, more dead volume was concentrated in dominant trees than in intermediate or suppressed trees.