Biomass and Productivity of an Alder Swamp in Northern Michigan

Total aboveground dry weight biomass and annual production were determined for two sites of different soil texture in an alder swamp of Michigan's upper peninsula. The more poorly drained site A averaged 5300 g/m2 and 640 g/m2 per year while site B averaged 3100 g/m2 and 570 g/m2 per year. The smaller standing-crop biomass on the better-drained site B is due to greater abundance of Alnusrugosa. The tree stratum constitutes 97 and 93% of the total biomass and 84 and 80% of the total production on site A and B, respectively. The understory strata constituted the remaining 3 and 16% of the biomass and production on site A and 7 and 20% on site B.