Notice that there are only a few shagbark hickories here, almost no smaller understory trees, and a large number of herbaceous plants. This area has been purposely altered by removing COMMON BUCKTHORN (Rhamnus cathartica), JAPANESE HONEYSUCKLE (Lonicera japonica), and EUROPEAN FLY HONEYSUCKLE (Lonicera xylosteum). Why cut down trees in a Forest Preserve? Buckthorn and the honeysuckles are weeds! You may have never thought of trees as weeds, but our definition of a weed is "any plant that is not where it should be." Buckthorn and the honeysuckles were introduced from Europe or Asia to provide food for wildlife. As with many species injected into an ecosystem to which they are not adapted, these `weed trees' do not fit in, but instead tend to take over and crowd out native plants.
The natural habitat here was OAK-HICKORY SAVANNA, a particular type of wooded area where trees are spaced so that the leaf canopy shades 10% to 50% of the forest floor. You might think of a savanna as half forest, half prairie, because many prairie plants are able to thrive among the widely spaced hickories and oaks. There are also some plants found here that only exist in the shade/sun combination of the savanna. Seeds and rootstock have probably remained dormant here for many years under the dense shade of those `weed trees,' but we hope that many kinds of sun-loving plants will grow again now that partial sunlight had been restored.