A study on forest succession in a northern lower Michigan cedar swamp.

A 0.25 acre plot was surveyed in a northern lower Michigan cedar swamp for changes in species richness, species diversity, and importance values of the species from 1932 to 1995. The plot is on a bog mat grounded on moist, sandy soil and was logged and burned extensively in the 1920's. Thuja occidentalis, Picea mariana and Abies balsamea are the dominant species in this plot. Diameter at 1.4 meters (DBH) was measured for the trees in the plot and compared with data from surveys in 1932, 1937, 1942, 1953, 1958 and 1986. Stand density declined for all three species from 1932 to 1995 although Picea mariana declined only slightly. Thuja occidentalis and Abies balsamea decreased and Picea mariana decreased in both relative dominance and importance values. Basal area increased for all three species from 1932 to 1995 and the size class distributions for the plot were consistent with what would be expected for a maturing plot over the time period. The tolerance and interference models of succession were used as explanation of the observed trends. The plot was predicted to maintain as a mixture of the three dominant species in 50 years.