During May and June, 1974, relevés were obtained from 30 plantation stands in the Saginaw Forest in southeastern Michigan. The canopy trees in these plantations were planted between 1904 and 1938. The understory has developed naturally over the years. The forest plantations offer opportunities for study of the effects of the canopy on the structure and species composition of the understory. A new numerical method of data structuring was used, which is based on the detection patterns of associated species within the table of 30 relevés from Saginaw Forest plantations. The method employs two difference measures. DIF 1 uses presence/absence data and DIF 2 the cover/abundance values obtained from the relevés. Both difference measures supply distance values for every pair of relevés. The least dissimilar relevés are then grouped together by the farthest neighbor agglomerative algorithm of Lance & Williams (1967). The DIF 1 analysis was inconclusive, but the DIF 2 analysis gave coherent results. It has shown that relevés with similar canopies have similar understories. The differences in understories among the relevés are due less to species composition than to the relative abundances of the species.
All Science Journal Classification (ASJC) codes
- Plant Science