Supporting Our Park’s Great Forests
Forest Park Forever's Park Ecologist Amy Witt (pictured below) recently wrote an essay for a new interpretive sign in Kennedy Forest to teach Park visitors a little bit more about the importance of forest restorations. The conservation methods used here in Forest Park are considered best practice for ensuring the health of our native forests. This blog post — timed to coincide with work happening in the forests this fall and winter — has been adapted from Amy's essay.
Missouri’s primary forest type is the oak-hickory forest, in which about 75% of the trees are oaks and hickories. The woodland wildlife in Missouri have evolved with this forest, depending on the nuts, buds, sap, dens, chemical impact and broader habitat ecosystem services these long-lived trees provide. Due to disturbance, fire suppression and human impact, there is an epidemic of unhealthy, overcrowded, and/or overly mature hardwood forests in the United States. An overly mature hardwood forest shifts from an open biodiverse environment into a forest where shade-tolerant trees such as maples, elms and ashes dominate the future canopy and invasive species, such as bush honeysuckle and garlic mustard, thrive at the shrub and ground layer. This transition is thought to be one of the greatest threats to the forests in the Midwest, because once a forest has shifted, intense management is required for a healthy forest to return. As we try to restore our forests to the grand oak-hickory forests that Missouri is famous for, prescribed burning, thinning and vegetation supplementation can be very important restoration tools.
Missouri’s awesome habitats, including its forests, evolved with fire. Fire every 5-25 years keeps the canopy open for a diverse herbaceous layer and young oaks to grow. In the absence of fire, these forests become overcrowded. At this stage, overall forest improvement needs to start with forest stand improvement. A periodic cutting of a tree stand can be used to create diverse benefits. In Forest Park, we use forest stand improvement to:
- Stimulate the growth of remaining trees
- Allow natural regeneration of chosen trees, such as oaks
- Improve forest complexity
- Enhance forest resiliency and diversity
- Create better wildlife habitat
Stand improvement is used as a conservation technique in the Park's two forests, highlighted above.
In our region, the factor that most limits tree growth, especially oaks, is access to sunlight. The simplest thing you can do to allow trees in a forest to grow strong is to decrease the competition they have for this life sustaining resource. Like weeding a garden to let vegetables grow stronger, forest stand improvement involves removing non-native, undesirable, unhealthy and poorly formed trees to allow desirable and ecologically important tree species to thrive. Dominant and released oaks often produce significantly more mast (the seed and fruit a tree or shrub produces). One dominant oak can produce more acorns than five suppressed oaks of the same age, and unlike a maple’s mast which quickly decomposes if not readily germinated, acorns can supply sustenance throughout the winter.
Forest stand improvement enhances a forest by increasing sunlight at its floor. Amazingly, in a healthy, open forest community, trees make up less than 5% of the species! The least biodiverse forest stage for plants and animals alike is the overly shaded, overcrowded forest, and that is what most of the forests and woodlands in Forest Park look like. An oak-hickory forest’s diversity shines at its lower levels, especially the ground story vegetation, which is why we assist the restoration process through additional native seed mixes and plantings. Keep your eye out for that rare bird or frog in a tree, as oak-based forests have been shown to have more birds throughout the year and increased amphibian success than maple and other shade-tolerant forests. When sunlight can reach the ground story, wildflowers, grasses, sedges and ferns will provide a great cover and filling buffet for wildlife such as birds, insects and small mammals. Insects and small mammals dine on the abundant low-lying seeds, leaves and buds while camouflaging with their surroundings, and birds keep a keen eye as they hunt this wildlife with increased ease.