Communities of the central hardwood forest have been dominated primarily by oak and hickory for the past 5000 years. Over this time period, they have become keystone species within the ecosystem and are of major importance in maintaining biodiversity. Not only do the large number of oak and hickory species by themselves contribute to community richness but they are known to provide food and support for a substantial number of wildlife species. Moreover, the structure created by dominance of oak and hickory in the foret community provides an environment for a highly diverse herbaceous understory. Data from oak-hickory stands with a maple-beech understory of saplings and small trees show a 90 percent drop in photosynthetically active radiation (PAR) at ground level accompanied by a 35 percent increase in litter weight compared to stands without an understory. The result is over a 90 percent drop in species richness and cover. This drastic loss of biodiversity, foliage, and fruit has serious implications for insect and bird populations and also suggests a potential for increased soil erosion and loss of nutrients. Extensive research into the loss of biodiversity is advised.