Hardwood-Conifer Forest Contact Zone in Itasca Park, Minnesota

Abstract

The hardwood forest and the northern conifer forest come into direct contact in Itasca Park. The problem of determining which may be climax is approached here on the basis of the relative competitive ability of the 2 communities. The maple-basswood (Acer-Tilia) community is found to be unable to invade the well established spruce-fir (Picea-Abies) community. From a study of soil moisture in undisturbed and trenched plots it is concluded that water is not of primary importance in preventing this invasion. Light intensity of < 5%, such as is produced by the spruce-fir forest, absolutely prevents the growth of the maple-basswood reproduction and ground cover. The dense sod produced by the fir roots is also a contributing influence. Some apparent infiltration of the hardwoods by elements of the conifer community sug-gests that recent climatic fluctuations favor the spruce-fir forest over the maple-basswood.