Vegetation and Soil Pattern in a Mesophytic Forest at Ithaca, New York

Vegetation and soil were sampled intensively in a 2-ha area of Mc- Gowan's woods, a rich, mixed deciduous forest at Ithaca, New York. The main vegeta- tation gradient was caused by moisture differences associated with a variation of 3 m in elevation, and Tsuga canadensis abundance caused a secondary gradient. The moisture gradient was accompanied by gradients in soil nutrients, pH and texture ; also the vegeta- tion gradient caused the mineral content of leaf litter to change. Hence, the mois- ture gradient is a complex gradient, with numerous variables changing together. Ordina- tion, particularly reciprocal averaging, was effective for analyzing these data. Correlation coefficients and canonical correlation analysis were less useful. McGowan's woods is exceptionally rich in species, probably because of disturbances. Its preponderance of phanerophytes and hemicryptophytes resembles southern or mid-temperate mesophytic forests.