A Good Home for Oaks

A Good Home for Oaks. . , The steep hills or "knobs" of Park Lyndon were created when the last glacial ice age disappeared some 12,000 years ago. As water flowed off the ice, it carried and then dropped huge amounts of sand and gravel. These soil ingredients, along with the steepness of the hills, provide fairly dry growing conditions and a sometimes droughty habitat., The dry conditions found in this forest area led to periodic fires in pre-settlement times. Oaks and hickories are both well adapted to fire. Even if the above ground portion is damaged by fire, vigorous growth allows them to quickly overtop other plants while drawing nutrients and water from deep root systems. Have you ever noticed how thick the bark is on a young oak tree? It protects the tree from light to moderate fires. Young maples and beeches, by contrast, have very thin bark and are easily killed in fires., When there are no fires in an oak-hickory forest for many years, its composition begins to change. Washtenaw County Parks staff has actively been working to preserve these forests of Park Lyndon by conducting prescribed burns and clearing invasive shrubs, which create too much shade for native plants to grow., Prescribed burns help keep this type of ecosystem healthy by: , . Discouraging the growth of less fire-tolerant species like maples. , . Enhancing the germination of native seeds in the soil by burning away the accumulated leaf litter , . Helping to eliminate invasive shrubs like autumn olive and honeysuckle, which are not well adapted to fire. , Know Your Oaks , The largest tree to the right and in front of you is a black oak. You can tell a black oak by its thick, dark bark with many short horizontal lines. Of the oak species in Park Lyndon, black oaks do the best in dry soils. The park is also home to other oaks. Can you see the differences in the leaves?