Overview

Eberwhite Woods is considered to be an oak-hickory forest. This means that oak trees and hickory trees make up a large portion of the mature tree population. The oak-hickory forest is a good environment for many beautiful wild flowers. Oak leaves and hickory leaves begin to grow late in the spring, in mid-May. The sunlight shines through the bare branches to the forest floor, giving the wildflowers plenty of energy to grow, bloom, and make seeds. Once the leaves come out on the oaks and hickories, the wildflowers have already gotten a good start and have stored plenty of energy in their leaves, stems, and roots.

Oak seedlings especially need a lot of sunlight to get off to a healthy start. When they are small, oaks use most of the energy they make from the sunlight to grow a deep taproot. The taproot grows straight down into the ground and is usually longer than the part of the seedling you can see above the ground. A deep taproot makes the young oak tree strong for three reasons: first, it is firmly rooted in the ground and cannot be easily pulled up or dug up by an animal; secondly, the deep root can reach moisture in the ground even when the soil at the surface is very dry; and third, a lot of energy is stored in the root, so the oak seedling can re-grow if its stem is broken off or burned off by fire.

Oak trees and hickory trees are both slow growing tree species. For this reason, invasive tree species which grow quickly, such as buckthorn and Norway maple, can move into the forest, dominating the space and creating large shady areas. The shade created by these invasive trees makes the regeneration of oak and hickory seedlings less successful.

In addition to making it hard for young oak trees to grow, invasive plants make it hard for wildflowers to grow. It takes a lot of energy to make flowers and seeds. The plants need plenty of sunlight. Invasive plants sprout leaves early in the spring, shading the forest floor. While the shade may not kill the wildflowers right away, the lack of sunlight will weaken them. The plants will make fewer flowers, fewer seeds. Also, the native plants will be more susceptible to fungus and disease.

What else can be done to keep forests healthy?

One tool that has been used to control invasive plants is fire. Using fire to control invasive plants is called a prescribed burn. Just as a doctor would prescribe a treatment for you when you are sick, foresters can prescribe fire as a treatment for a sick forest that has been invaded by invasives.

Oak trees, hickory trees, and most other native trees have thick enough bark and deep enough roots to survive a fire. Most invasive trees have shallow roots and thin bark and are killed by fire. The right time to use fire is in the spring or in the fall. In the spring fire would be used when the invasive plants have come up but the native plants are still dormant under the soil. In the fall fire would be used after the native plants have bloomed and faded, but the invasive plants are still growing and storing sunlight energy.

In a fire, roots of native plants are safely protected under the ground. Native seeds usually survive fire. Animals in the burned area see k shelter in water, under logs and rocks, or in areas away from the danger. Unfortunately, a few animals are killed by prescribed burns. Caterpillars and insect eggs on burning leaves are unlucky victims. For this reason, most prescribed burns are done in some sections of a forest, but not in others. This way only some insects are killed, while the others can grow up to reproduce.

How do trees make energy from sunlight?

Plants use sunlight to make energy to grow. The green stuff in the leaf cells, called chlorophyll (KLOR-A-FILL), absorbs energy from the sunlight that shines on the leaf. Then a series of chemical reactions in th e plant cell 8transforms the light energy into sugars. The tree uses the sugar to grow new cells and to repair any damage that it may have had.

Your body uses sugar for energy, too. You do not make sugar from sunlight, but you do eat sugars that plants have made by capturing sunlight energy. You use that energy to grow, to repair injuries such as scrapes and cuts, and to move your body. So your body uses energy from the sun!

In addition to sugar, plants that we eat provide us with vitamins, minerals, and protein. When you think about it, even meat comes from animals that ate plants. The energy from the plants made their bodies grow. The suns energy is responsible for sustaining life on earth.