Restoring Longleaf A Groundcover Perspective

In addition to the traditional interest in longleaf timber production, many landowners have come to appreciate the value in managing forests that supports plant and animal diversity as well as the overall health of the ecosystem.

Not all landowners are fortunate enough to possess a mature, fully-functioning longleaf forest. If you are one of the lucky few, thank you for being good stewards of the land and doing your part to maintain it for generations to come. If lost, groundcover is definitely the hardest part to restore. For others, who may be establishing longleaf on formerly cultivated lands or converting forested lands back to longleaf, it is a significant undertaking to achieve both the short and long term goals of restoration. Whether you are managing for recreation, timber, hunting, non-game wildlife, or aesthetics, the building blocks for a functional forest system include not only an open canopy of longleaf, but also a healthy herbaceous groundcover layer. This document will provide you with some tips on how to restore and maintain appropriate groundcover species that will help you achieve your management objectives.

Clockwise from top left: Bobwhite quail (credit Brady Beck), Fox squirrel (credit Brady Beck), Gulf frittilary on blazing star (credit Christa Hayes), Gopher tortoise (credit Randy Tate)

Groundcover performs many roles in the longleaf forest. One of the most important qualities of herbaceous groundcover is its ability to support the frequent fires that are central to managing longleaf. The numerous grass species that dominate the landscape, provide essential fine fuels that feed these fires. If fire is part of your management scenario, then your stands must have some form of consistent herbaceous groundcover.

The regular use of frequent fire as a management tool directly influences the diversity or species richness of a site. Without fire, the forest structure changes from a plant community that is dominated by herbaceous species to one that is primarily woody shrubs and trees. The open, park-like nature of a healthy longleaf forest allows for more sunlight reaching the forest floor that is needed to support the wide variety of herbaceous species that are found in this system. The diversity of the longleaf ecosystem is directly linked to the quality of that existing groundcover layer. As this layer becomes more diverse, you will notice a corresponding increase in animal diversity.

A rule of thumb to consider is that each new plant species provides for 10 new insect species. All these little things provide food for the bigger things.

Rare bird species like red cockaded woodpeckers and Bachman’s sparrows, game species such as bobwhite quail and wild turkey, and also reptile species like gopher tortoises and indigo snakes thrive in early successional habitats with abundant herbaceous plant species. Herbaceous species and low-growing shrubs provide cover, food, and habitat for these and many other animal species. Flowering groundcover species are also very important in supporting native pollinator populations under pressure across the US.

RCW with grasshopper. Photo credit: Brady Beck.
The Restoration Process

Restoring longleaf habitat from the ground up can be daunting. There is still much to learn about establishing and managing for this component of the longleaf forest. However, if you form realistic objectives based on your property’s current condition and land classification and follow a solid restoration plan, you can greatly improve the condition of the groundcover on your land.

The primary groundcover restoration steps include:

1. Assess current conditions

2. Develop a realistic restoration plan

3. Site restoration & management

Assess current conditions

Before embarking on a restoration project, learn all you can about the land to be restored. What is the current condition? Is it former agricultural land or was/is it forested? If it is forested, what is the dominant canopy species? What groundcover species do you already have? Are there invasive species present? What is the community type? What is the soil type? Where is it located geographically? These are just a few of the questions that should be answered in order to develop realistic objectives and expectations for restoration. Your starting condition will dictate the level of restoration required to meet your objectives.

To set reasonable objectives, the desired future condition for the site must be determined. The answer is based upon your site assessment questions, historical knowledge of the site, and/or condition of similar properties that can serve as reference sites. An accurate determination is very important since your restoration success can be assessed against these reference conditions.

Factors that Help Determine the Desired Future Condition

Soil Type - Moisture Content

Plant Composition - Geography - Land Use

What is your reference condition? Clockwise from top left: Flatwoods, Wet savanna, Mesic Rolling hills, Sandhill (photo credits Carol Denhof).
Develop a realistic restoration plan

With your overall strategies in place, it is time to consider the specifics of restoring your longleaf forest. Each site is unique and so is the restoration plan. This plan will be greatly influenced by your starting conditions. As discussed, highly impacted sites will require a much heavier hand in order to reach restoration goals. Consider incentive programs or other resources that may help you reach your objectives.

Based on the desired future condition, realistic short-term and long-term objectives can be set that will achieve restoration goals. It's important to understand that it is a multi-step process and does not happen in one season.

In the chapter dedicated to ground layer restoration in the book "The Longleaf Pine Ecosystem: Ecology, Silviculture, and Restoration", Joan Walker and Andrea Silletti discuss in depth all aspects of groundcover restoration. Especially interesting is the graphic above which displays the relationship between time and resources needed for restoration and the abundance of remnant biota on the site to be restored. The take home message is know what you have to start with and form realistic expectations based on that knowledge.
Site restoration & management

The physical process of groundcover restoration addresses the following factors:

Competition - Biodiversity - Management

Controlling Competition

Having a good understanding of your site based on past land uses and the current condition of the land is very important in determining the actions taken to control the competition on a site. A variety of control methods can be used including fire, herbicide, and mechanical treatments. The method used will be determined by not only the species you are trying to eliminate or minimize, but also the species you are trying to keep. Whether it is non-native cogon grass or naturally occurring scrub oaks, undesirable vegetation must be brought under control in order to enhance or establish native groundcover species. Many of our most desired groundcover species develop gradually at first, and aggressive competitors will grow faster and quickly overtake the species you are trying to establish.

Care must be taken to preserve any quality groundcover species on the site. The intensity level of site preparation needed for a restoration project will be determined by a number of factors: site type (cutover vs. oldfield sites), amount of competing vegetation on the site, and the presence of aggressive invasive plant species (e.g. cogongrass). If using herbicides as part of your site prep treatment, the choice of chemicals will determine the impacts on the beneficial species that you already have and want to retain.

Clockwise from top left: Using non-selective herbicides will eliminate all groundcover species (credit Nathan Klaus); Use of selective herbicide (Metsulfuron in this example) will retain important fine fuels that are needed for management (credit Nathan Klaus); Certain oldfield pasture grasses such as bermuda grass require an intense herbicide treatment to control prior to native seed establishment (credit LLA); Invasive species such as cogongrass also require repeated herbicide treatments to control (credit UGA).

Increasing Biodiversity

In some cases fire alone may increase biodiversity. This is generally the case in cutover and forested sites that have been unburned for extended periods. However, in areas without existing native groundcover, the desired species diversity must be created. This can be done through seeding or planting seedlings. Species composition will be determined based on habitat and landowner objectives. No matter the species, it’s important to consider using ecotype plant material that is adapted to your specific geographic area.

When creating seed mixes, the main plant groups used include (l-r) composites, grasses, and legumes. To increase diversity and create habitat for pollinators, milkweeds are often added to the mix. (photo credits Carol Denhof)

When establishing new seed or plant material, a challenge many landowners face is finding a good source for the material. It can be obtained through commercial seed producers, nurseries, or donor sites. There are several commercial seed producers and nurseries that supply native ecotype material for the southeastern US. The Longleaf Alliance keeps an updated list of recommended suppliers and also experienced contractors on our website: https://longleafalliance.org/what-we-do/restoration-management/resources.

Native legume seed grown by Lolly Creek Farms (credit Carol Denhof).

Another source that our agency and non-profit partners have used extensively is seeds collected from donor sites that have high quality groundcover. This allows for better site matching since the seed collected is used on adjacent restoration sites, and also a broader suite of species that can be restored at once.

The planting process can be done using a variety of methods. Either plugs or seeds can be used. Typically seed planting is done with a no-till grain drill (e.g. Tru-Ax drill or Grasslander) on oldfield sites with a minimal amount of large debris or stumps. On cutover sites, broadcasting the seed may be a better option. Plugs can be planted by hand or with a mechanical planter if planting on open sites.

Clockwise from left: Modified hayblower used at Ft. Stewart, GA to broadcast bulk seed collections in restored flatwoods habitats; Mechanical planter used to establish native groundcover plugs in field at Lolly Creek for seed production; Grasslander seed drill planting bulk seed collection at Moody Forest Natural Area. (photo credits Carol Denhof)

Site Management

Burn, burn, burn! The longleaf forest is dependent on fire to maintain ecosystem health and its high biodiversity. The groundcover makes this happen. Burning on short rotations and in varying seasons will allow herbaceous species to grow and flourish through encouragement of flowering, seed set, and seedling recruitment.

Fire is the most natural form of forest management that we employ. The groundcover species that occur in longleaf habitats have evolved with fire, and many require fire to flower and set seed for reproduction. Species such as wiregrass will only produce viable seed if burned during the "lightning season" which is April-June. This would have been the time when natural wildfires would have been ignited by lightning strikes.

(l-r) Grasspink, Goat's Rue, American Chaffseed, (photo credits Carol Denhof) and Wiregrass (photo credit Ryan Mitchell) all exhibit positive flowering responses to fire.

Mechanical and chemical methods are also used for managing sites when fire is not effective or not an option. These are especially useful in situations where spots of invasive species need to be treated or if woody shrubs and trees in the midstory need to be removed. These treatments should lead to the eventual transition to fire as the main management tool though.

So, if you are interested in starting on this adventure of longleaf restoration, please consider including a groundcover component in your plans. After all, we are working to restore the longleaf ecosystem, and without the groundcover we are really only painting half of the picture.