Timber Stand Improvement

What It Is

Timber Stand Improvement (TSI) is the selective removal or killing of less-desirable trees in a stand to favor the species, size classes, and structure that deliver higher ecological value — and in some cases, higher timber value as well. In the Cumberland Plateau region, TSI is most often used to open closed-canopy hardwood stands that have become fire-deprived, to restore light to the forest floor, to favor oak and hickory regeneration, and to prepare a stand for prescribed fire.

TSI is often the necessary first step before prescribed burning can be effective in closed hardwood forest. The closed canopy must be partially opened so that enough light reaches the forest floor to support ground-layer vegetation — the fuel that carries prescribed fire — and the openings themselves benefit wildlife long before the first burn occurs.

Why It Matters

Decades of fire exclusion across the Cumberland Plateau have produced dense closed-canopy forests dominated by fire-sensitive, shade-tolerant species — red maple, sweetgum, tulip poplar. These forests may appear healthy and beautiful, but they function narrowly as wildlife habitat. The closed canopy blocks sunlight, understory vegetation thins out, mast production from remaining oaks drops, and ground-level food and cover for game species largely disappears.

TSI addresses this by selectively removing the species that shouldn’t be dominant and releasing the oaks, hickories, and pines that support diverse wildlife communities.

Species to remove: Red maple, sweetgum, tulip poplar dominate the removal list. Eastern red cedar is reduced (not eliminated) in glade and grassland contexts. American beech is not on the removal list in this region — it is not sufficiently dominant in the target counties.

Species to favor: White oak, red oak group, hickories (wildlife mast), shortleaf pine (where present), black cherry, persimmon, white ash (protect due to emerald ash borer pressure).

How It’s Done

• Selective thinning: chainsaw-fell undesirable trees; slash can be left or piled
• Girdling: cut through bark and cambium around the trunk; the tree dies standing, creating snag habitat for woodpeckers and cavity-nesting birds
• Hack-and-squirt: girdle plus herbicide application for reliable kill; fall application is often most effective when plants are storing carbohydrates for winter
• Crop tree release: remove competitors within 10–15 feet of desirable trees to open their canopy

Basal area targets:

• Savanna: 20–40 sq ft/acre
• Open woodland: 40–60 sq ft/acre
• Managed forest: 60–80 sq ft/acre
• Unthinned closed forest: often 100–120+ sq ft/acre

Timing: TSI can be done year-round but dormant season is preferred — easier to see stems, identify species, and work in cooler conditions. TSI should precede burning by at least one growing season so killed material dries and becomes fuel for fire.

Expected Outcomes

• Immediate: increased sunlight reaching the forest floor; flush of herbaceous growth the first growing season
• 1–3 years: increasing diversity of wildflowers, grasses, and woody shrubs; improved deer forage
• 3–5 years: oak and hickory seedlings establishing in openings; improved conditions for quail and turkeys
• Long-term: restored woodland structure supporting diverse wildlife community; conditions to sustain prescribed burning