Forest Stand Improvement

Kevin Mertz

Forest Stand Improvement (FSI) is a term and technique that may be considered by some as ambiguous, and by others as under-utilized. Let’s set the record straight on what it’s all about, why we should consider adopting this practice, and a notion of how to go about doing it.

Timber Stand Improvement (TSI) is a more familiar concept than FSI is. Its focus primarily considers timber value for a future harvest, whereas the purpose of Forest Stand Improvement is driven by improving wildlife habitat and native ecosystem restoration. This is an important distinction, as FSI offers more flexibility in the way the timber stand in question is managed. A consulting forester would almost never recommend hinge-cutting or prescribed fire as a means to improve timber value, whereas a wildlife biologist or ecosystem consultant are more likely to suggest these kinds of practices. Having said that, implementing FSI doesn’t necessarily mean we need to abandon the thought of improving timber value throughout the stand. There’s room to improvise, retain timber value for future harvest, while at the same time maintaining the primary objective of improving wildlife habitat. Forest Stand Improvement may be incorporated at any point from one timber harvest to the next, and in fact both of them may be used together as part of an overall management strategy.

The foreground in this photo depicts the result of sunlight being allowed to reach the forest floor, with early successional grasses, forbs, shrubs, and other woody vegetation represented. The background illustrates the amount of shade present in a closed-canopy environment.

Wildlife management is a combination of art and science, and FSI tends to fall a bit more into the art side of the equation. There isn’t necessarily a right and wrong way to do it, although there are some general guidelines to consider. First and foremost, FSI is primarily concerned with opening up a forest canopy and allowing sunlight to the ground. At some point in the successional process, a close spacing of trees begin to result in crowns which touch or overlap, in the process robbing ground-based vegetation (understory) of needed sunlight. Closed-canopy forests now dominate a significant portion of the wooded landscape, especially in the eastern half of the U.S. Defined as a forest environment with canopy closure of 80% or more, these areas will derive the most benefit from the implementation of Forest Stand Improvement. Much of this closed-canopy forest is in private land ownership, and has reached this state due to the lack of management in these forested landscapes.

Table 1: General Characteristics Comparing Forest, Woodland, and Savanna Ecosystems

Canopy closure of approximately 50% is a common recommendation in FSI plans that attempt to replicate native woodland habitat, which ideally consists of a preponderance of forbs and other early successional vegetation occupying the understory. These plants are a vital component that we want to strive for to produce great wildlife habitat. They offer excellent nutrition and security for white-tail deer, great structure for ground-nesting birds such as wild turkey and bobwhite quail, and food and cover for many other species as well. Canopy cover approaching 80% or more open ground (20% canopy closure) is likely to result in a savanna-type ecosystem, which offers much of the same benefits that woodlands do, but with fewer trees. A high portion of canopy closure (between 50-80%) will still provide some wildlife benefit to a point, but is likely to include more woody vegetation and fewer forbs existing in the understory. Prevalent use of prescribed fire will result in and maintain a high proportion of forbs, a beneficial component of the understory for wildlife. Herbicide may be applied to woody vegetation to promote grasses and forbs as well.

Another important consideration when conducting FSI is habitat diversity and spatial arrangement of habitat types. Game animals have different food and cover requirements that change throughout the year. FSI can be applied in a way that promotes habitat diversity by using different techniques and strategies across a given property. This is where the artistry comes into play. Sections of closed-canopy forest may be left alone to promote squirrels, turkey strutting areas, or areas where deer travel through quickly as a few examples. Other areas may be targeted as deer staging or bedding areas, or turkey nesting, brooding, or loafing zones. On property that includes terrain features, slope aspect and topography should be factored into the management plan. Prescribed fire may be incorporated as a follow-up maintenance tool using various return interval rates. FSI may dovetail other management efforts such as an overall hunting strategy or developing silvipasture for grazing livestock. The possibilities are nearly endless, and should be very specifically tailored towards your goals and objectives, and the land you are fortunate enough to oversee.

Regardless of your unique situation, and how your FSI plan is mapped out, it does require manual labor to be completed successfully. Sure, a forestry mulcher or similar type of equipment has the ability to remove trees, but it won’t produce the same results as a proper FSI treatment. The first step is to analyze individual trees within a stand and decide what to do with them. Obviously that starts with having the ability to accurately identify the most common tree species that occupy your timber stand. Then you must evaluate the stand based on your objectives, by asking yourself the following kinds of questions:

• Is there a component of invasive/exotic plants in the stand that need to be addressed?
• What kind of wildlife value, if any, does the tree being considered pose?
• Is the individual tree a good specimen to leave for future timber or mast value, or should it be taken out?
• Should you cut a tree down to generate more structure in that specific location, or leave it standing to encourage uninhibited wildlife travel?
• If felled, should the stump be top-killed or allowed to re-sprout?

Once you’ve developed a knack for making these types of decisions on the fly, it’s time to start applying Forest Stand Improvement techniques. These include, but are not limited to, felling, hack-and-squirt, girdle-and-spray, and hinge-cutting. At minimum, these methods can typically be achieved using a chainsaw, hatchet, herbicide, spray bottle, all the necessary Personal Protection Equipment (PPE), possibly more.

After applying these methods, it’s time to analyze what’s been completed. What kind of canopy closure did you end up with? What is the vegetative and wildlife response after a period of time? This requires follow-up visits weeks, months, and even several years after the initial treatment to gauge effectiveness of the initial application, and the current condition of the stand. You may consider deploying trail cameras in completed sections to monitor wildlife use somewhat objectively. In many cases, follow-up observations will dictate incremental management actions such as additional thinning of remaining trees, invasive species removal, adding or removing structure to enhance wildlife use, use of prescribed fire, among many other possibilities.

FSI can be applied on any scale that works best for you. If you have a lot of help available you can manage hundreds of acres, and even a do-it-yourselfer can expect to tackle a few acres at a time, even less. Either way, it’s worth the effort. You can expect a quick and significant response in terms of wildlife utilization, and a gratifying hunting experience as a result. Further, FSI is a practice that is recognized by various state and Federal cost-share programs, with EQIP from the NRCS being one example. In addition to supplying great wildlife habitat, FSI is also extremely cost-effective compared to other practices such as food plots and supplemental feeding. All it requires is an investment of $1000 or less for the right equipment, some sweat equity to go along with it, and a desire to stay safe during the process. With the use of those tools you can vastly improve your forested environment for a myriad of wildlife, including many individual plants and animals, and at an ecosystem level as well. There is something spiritually therapeutic about conducting FSI and having land stewardship top of mind while you’re at it.

A single individual can generate a positive influence on wildlife habitat by opening holes and pockets in the forest canopy in meaningful fashion.

Forest Stand Improvement may be one of the most underrated wildlife management practices in the eastern United States. What are you waiting for? If you have an unmanaged or closed-canopy forest to deal with, start your FSI project today, or progress to the next level if you’ve already started. Enjoy the process of educating yourself and becoming a better woodsperson in your FSI journey, and in doing so you shouldn’t have any regrets when it’s all said and done.

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