The concept of maximizing flora diversity is nothing new. While it may have slipped by unperceived as we beat our way through the daily grind of managing lands, our management practices were promoting diversity in many ways. Whether we were burning old fields, conducting thinnings, protecting wetlands, controlling non-native species, daylighting roads, etc., we were, in fact, promoting flora diversity. Drawing back to your earliest biology lessons, I am sure you realize the importance of plants. Unfortunately, very few (including myself) truly understand just how important plants are. Sure they play a big role in oxygen and carbon dioxide cycles, serve as the primary producers in food chain systems, provide critical habitat to wildlife species, cleanse runoff and protect watersheds, and provide countless materials important to civilization (food, fiber, medicine, etc.). Even still, there are countless services provided to this planet by plants. The benefits of flora diversity are no surprise to serious wildlife managers. Looking at species trends across the globe, it is pretty easy to recognize that the most diverse wildlife communities are almost always in the areas with high flora diversity.
In order to successfully plan for improving flora diversity, it is important to consider a few things. What plants are present on the landscape currently? How are plant communities distributed across the landscape? What percentage of the property is in commercial timber? What are the age class distributions of pine plantings? Are there areas on the property that may harbor unique plant communities? Ephemeral wetlands, forest coves, pockets of distinctly different soils, etc.?
Once you understand what is currently available, you can begin to develop a plan of action for increasing flora diversity. In most situations, we can increase diversity without planting anything. It’s as simple as providing an opportunity for plants to grow. Many management practices accommodate this. In forested landscapes, thinning timber allows sunlight to reach the forest floor, which will promote vegetative growth. By diversifying thinning rates or stand densities, we can develop a broader catalog of plant species present. Consider developing a mosaic of stand densities within commercial timber stands.
Prescribed fire is an extremely important tool for managers looking to diversify flora. Typically, land managers attempt to get all of their burns completed in the short period between late fall and late winter. While this time frame is well suited for encouraging native plant regeneration, it will likely fail to help the property meet its diversity potential. Fire can be manipulated in several ways to encourage plant diversity. First, fire timing and frequency play a big role in determining which species repopulate the area. If all burns are conducted in a short period of time, the respective flora communities will be comprised of similar species. Managers who have the ability to burn throughout the year will quickly see the difference in plant communities for respective burn times. Sure there will be many species that overlap each burn time, but each will likely contain a few species not found in other burn time periods. The more diverse we make our burn times, the greater the possibility of reaching our flora diversity potential. The same can be said for burn frequency. Burning everything annually or biennially may bottleneck our potential. Diversifying burn timing and frequency can have a huge impact on species diversity on most properties. Another important variable with respect to fire is intensity. Fire intensity can be manipulated thru firing technique, weather conditions, fuel availability, etc. The firing technique is the easiest way for managers to diversify fire intensity across the landscape. It doesn’t all have to be back fires and strip head fires. Mix it up. Ideally, the property should be a mosaic of various firing times, frequencies, and intensities.
Another technique is softening edges. The concepts of feathering forest edges, field borders, and daylighting roads are well known for their value to wildlife communities. These practices typically produce plant diversities greater than either of the two habitats they separate. It is common to find wildlife and plant species representative of interior and edge communities intermingled where we have softly transitioned from one plant community to another. Developing smooth transitions from one forest stand to another is rarely done, but this can easily be incorporated into harvesting and replanting operations. On large commercial timber operations, feathering edges between every timber stand can provide substantial wildlife habitat. Managing these feathered areas to prevent them from reverting to dense forests ensures the plant communities and wildlife habitat will persist thru the aging of the forest stands.
Invasive species management is another method of promoting flora diversity. Invasive species tend to take over areas and greatly restrict species richness. In South Carolina, privet is a great example. Chinese privet has made its way across our beautiful state, and many of our hardwood bottoms and riparian forest understories are now dominated by privet. The ability of privet to shade out the forest floor can be devastating to native plant communities. Regardless of the invasive species present, we have the tools to reduce, control or possibly eradicate the invasive. Herbicides are often the tool of choice for removing invasives from the landscape. Some situations require mechanical methods combined with herbicide applications. Efforts to control invasives can be rather daunting and often disappointing. The key is to stay persistent. In the case of species like privet, the manager may find themselves locked in an eternal battle of good versus evil. It becomes easier to tackle the annual control efforts once the rewards become visible. Species, hopefully desirable species, will fill in when the invasives are controlled.
Planting is another method of increasing flora diversity. Today’s managers are fortunate in that there are a multitude of native plant nurseries. A quick internet search will locate several options for just about any native grass, herb, shrub, or tree species you wish to plant. One can also harvest desirable seeds or seedlings throughout the year. Regardless of whether we are discussing old field habitats or mature hardwood forests, the goal is to improve diversity by incorporating native species not currently present or plentiful. Forest may benefit from selective removal of dominant or undesirable species. Following the removal of selected trees, desirable tree species can be planted in the openings. Forest stands frequently lack sub-canopy structure. Consider incorporating native shade-tolerant shrub species and understory herbaceous plants. This will not only improve diversity but also assist with developing a quality multi-layer forest. Old fields and open areas can be planted with a wide variety of native grasses and broadleaf plants. Native plant nurseries can custom blend a seed mix to supplement the species currently present at the site. These seed mixes can be developed to support a variety of desired wildlife species, from butterflies to deer.
Opportunities to improve flora diversity go far beyond the methods mentioned in this article. The most important thing to remember is flora diversity requires management diversity. We have to manage with developing a mosaic of plant communities in mind. Break up those burn blocks, and broaden your burn timing, frequency, and intensities. Let’s get some sunlight to the ground in those forest stands. Don’t be afraid to incorporate plantings of desirable species. Keep the invasives in check, and let the good times roll.
Management Practice Examples
Collection of native grass and herb seeds for future plantings.
Field border examples
Examples of native plant regeneration following herbicide applications to control invasive Chinese privet in Chester County.
Example of prescribed fire
Pollinator habitat demonstrations have been installed at Clemson’s Pee Dee and Sandhill Research and Education Centers.
Early successional plant community management demonstration at Clemson’s Sandhill Research and Education Center. In this demonstration area, a utility right of way was divided into ¼ -1/2 acre plots. Plots were assigned to one of the following treatments: annual growing season disk, biennial growing season disk, annual dormant season burn, biennial dormant season burn. The patchwork of disturbances produces a diverse array of native grasses and broadleaf plants.
This article was originally featured in the Summer 2021 Version of CU in The Woods newsletter.
Author(s)
W. Cory Heaton, Cooperative Extension, Forestry and Wildlife Specialist
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