Timber Stand Improvement: How to Improve Your Woods for Wildlife and Property Value

Why TSI Is the Best Investment You Can Make in Your Timber

I put off timber stand improvement for years. The woods behind my property were a mess of box elder, elm, and honey locust crowding out a solid understory of white oak and black walnut. I figured nature would sort it out. It did not.

What finally pushed me was walking through a neighbor's woods after he had a forester do TSI work. The difference was shocking. Sunlight hit the forest floor. Native browse was coming up everywhere. His remaining oaks had visibly wider crowns. It looked like a completely different property, and he told me deer were using it three times harder than before the work.

TSI is straightforward: you identify the trees that have no future (junk species, damaged trunks, poor form) and kill them standing, so the trees worth keeping get all the resources. The dead trees eventually become wildlife habitat themselves as snags and down logs. Nothing is wasted.

The economics are real. A well-managed timber stand can be worth 2 to 3 times what an unmanaged stand is worth per board foot at harvest. The USDA Natural Resources Conservation Service (NRCS) considers TSI important enough to cost-share it through their EQIP program at up to 75% for qualifying landowners. That should tell you something about the return on investment.

The Three TSI Methods Every Landowner Should Know

1. Hack-and-Squirt: The Workhorse Method

This is where most people should start. You take a hatchet, chop a downward cut into the bark of the target tree at a comfortable height, and squirt herbicide into the cut. The tree pulls the herbicide into its vascular system and dies over the next growing season. It stays standing as a snag, which woodpeckers, owls, and flying squirrels love.

What you need:

• A sharp hatchet or the Forestry Suppliers Hypo-Hatchet Tree Injector which hacks and injects in one motion
• Garlon 4 Ultra (triclopyr) herbicide — the standard for hardwood TSI
• A squirt bottle or trigger sprayer — old dish soap bottles work fine. One squeeze delivers roughly 1 ml, which is what you need per cut
• Nelson tree marking paint to mark treated trees so you do not double-treat or miss any
• Chemical-resistant gloves and eye protection

The recipe: Mix Garlon 4 Ultra with a carrier. The common ratio is 1 part Garlon to 3 parts basal oil or diesel fuel for basal bark treatments, but for hack-and-squirt you can use it undiluted or mixed 50/50 with water. I use it undiluted for big trees and 50/50 for anything under 6 inches in diameter. The Penn State Extension recommends making one hack per 3 inches of trunk diameter and applying about 1 ml of herbicide per hack.

Timing matters: Late summer through mid-fall (August to October) gives the best results. The tree is actively moving sap downward to the roots, so it pulls the herbicide into the entire root system. Avoid treating in spring when sap is rising — the herbicide tends to weep out of the cuts instead of being drawn in.

2. Girdling: No Chemicals Required

Girdling means cutting a ring around the trunk through the bark and cambium layer, severing the tree's ability to transport water and nutrients. The tree dies slowly over 1-2 growing seasons.

I use girdling on trees where I do not want herbicide near water — along creek banks or near my pond. A Husqvarna hatchet works well for smaller trees. For larger trunks, I make two parallel cuts about 4 inches apart with a chainsaw and peel the bark between them. The key is cutting through the cambium layer completely around the trunk. Miss even a 2-inch bridge of cambium and the tree will survive.

The downside: Some species are stubborn. Elms and maples can sometimes bridge a girdle with new tissue. For those, I either make the girdle wider (6+ inches) or follow up with hack-and-squirt if they are still alive after one season.

3. Hinge Cutting: TSI That Creates Instant Cover

Hinge cutting is where you cut partway through a tree trunk (about 70-80%) and push it over so it stays alive on the remaining hinge of wood and bark. The tree falls but continues to grow laterally, creating a wall of thick cover at ground level. This is the gold standard for creating deer bedding areas.

I covered hinge cutting in detail in my hinge cutting for deer bedding guide, so I will keep it brief here. The main thing to understand is that hinge cutting is both TSI and habitat creation in one move. You are removing a junk tree from the canopy competition while simultaneously building ground-level cover that deer, rabbits, and songbirds use immediately.

Best candidates for hinge cutting: Trees 4-8 inches in diameter of species you want to eliminate anyway. Box elder, elm, ironwood, and sassafras all hinge well. Do not hinge cut your valuable hardwoods.

Timing: Late winter (January through March) when leaves are off and you can see the timber structure clearly. This also avoids disturbing nesting birds and gives the hinged tree all spring and summer to leaf out and establish lateral growth.

Which Trees to Keep and Which to Kill

This is where a lot of landowners freeze up. Nobody wants to kill a healthy tree. But the truth is, a crowded timber stand full of junk trees is not a healthy forest — it is a slow-motion competition where everybody loses.

The Keepers (High-Value Hardwoods)

• White oak — The king. High timber value, produces acorns every year that wildlife depends on, and lives for centuries. Never cut a healthy white oak during TSI.
• Red oak — Good timber value, produces acorns on a 2-year cycle. Keep all healthy specimens.
• Black walnut — Extremely high timber value ($2,000+ per tree for veneer-quality logs). Walnut responds dramatically to TSI because it is shade-intolerant and needs full sunlight to develop valuable straight trunks.
• Black cherry — Valuable timber species and excellent wildlife food. Keep healthy, straight specimens.
• Sugar maple, hickory, tulip poplar — All solid keepers with decent timber value and wildlife benefits.

The Targets (Remove These)

• Box elder — Weak, fast-growing, zero timber value. The first thing I hack-and-squirt on any property.
• Elm — Most are doomed to Dutch elm disease anyway. Low timber value. Remove.
• Ash — Emerald ash borer has killed or is killing ash across the eastern US. Dead and dying ash should be removed for safety. Standing dead ash becomes brittle and drops limbs unpredictably.
• Honey locust — Thorns make it a hazard, and it has minimal timber or wildlife value in a managed stand.
• Invasives: bush honeysuckle, autumn olive, Bradford pear — These are not just junk — they actively suppress native regeneration. Kill them first.

When in doubt, keep it. If you cannot identify a tree, mark it with marking paint and come back with a field guide or a photo for your county extension agent. You can always kill a tree later, but you cannot unkill one.

Tools and Gear for TSI Work

One of the best things about TSI is that you do not need expensive equipment. Here is my actual gear list for a day of hack-and-squirt work:

Item	What I Use	Why
Hatchet	Husqvarna 13" Wooden Hatchet	Light enough to carry all day, sharp enough for clean hacks
Herbicide	Garlon 4 Ultra (Triclopyr)	Industry standard for hardwood TSI. Controls 55+ woody species
Applicator	Old dish soap squeeze bottle	Delivers ~1 ml per squeeze. Free. Replace when solvent degrades it
Marking paint	Nelson Tree Marking Paint	Mark treated trees so you track progress and avoid double-dosing
Chainsaw	Husqvarna 455 Rancher 20"	For girdling large trees and hinge cutting. 55cc is plenty for TSI
Safety gear	Husqvarna Protective Power Kit	Chaps, helmet, gloves in one package. Non-negotiable for chainsaw work

If you are doing a lot of hack-and-squirt work, the Hypo-Hatchet Tree Injector is worth considering. It hacks and injects herbicide in one swing, which speeds up the process significantly on high-density stands. It is more expensive and requires cleaning after every use, but on a big project it saves hours.

For any work involving a chainsaw, read my guide on chainsaw safety gear for land work. Chaps, helmet with face screen, hearing protection, and steel-toe boots are the minimum. I have seen chainsaw injuries in person and they are life-altering.

Best Time of Year for TSI

Your calendar for TSI work should look like this:

• January - March: Hinge cutting season. Leaves are off, you can see the stand structure, and you are not disturbing nesting birds. Ground is often frozen enough to walk without tearing up the forest floor.
• August - October: Hack-and-squirt and girdling season. Trees are actively transporting sap downward, which carries herbicide into the root system for a complete kill. Mid-September to mid-October is the sweet spot in my area (Southern Indiana, USDA zone 6b).
• Avoid April - July: Nesting season for songbirds, sap is rising (reduces hack-and-squirt effectiveness), and the heat and humidity make all-day woods work brutal.

What to Expect: A Realistic Timeline

TSI is not instant gratification. Here is what I saw on my property after treating roughly 5 acres of mixed hardwoods:

• Month 1-3: Treated trees start showing stress. Leaves yellow and thin. Hack-and-squirt trees may not show signs until the following spring.
• Year 1: Most treated trees are dead or dying. Sunlight starts reaching the forest floor. You will notice more ground-level vegetation almost immediately.
• Year 2: Native browse species fill in the understory. Blackberry, greenbrier, pokeweed, and native grasses appear where bare dirt used to be. Deer start using the area differently — more habitat improvement results become visible.
• Year 3-5: Remaining keeper trees show noticeable crown expansion. Understory is thick and diverse. Snags from killed trees are being used by cavity-nesting birds. The timber stand looks and feels like a different property.
• Year 10-15: Timber value of remaining trees has increased substantially. The stand is healthier, more diverse, and worth significantly more per board foot than an unmanaged stand.

EQIP Cost-Share: Let the Government Help Pay for It

The USDA Natural Resources Conservation Service (NRCS) runs the Environmental Quality Incentives Program (EQIP), which cost-shares forestry practices including TSI at up to 75% for qualifying landowners. If you have 10+ acres of woods and are willing to follow a forest management plan, it is absolutely worth applying.

Contact your local NRCS office (find it at nrcs.usda.gov). They will send a forester to walk your property, write a management plan, and if approved, reimburse you for most of the work. I have talked to landowners who got TSI done on 20+ acres essentially for the cost of their own labor.

Common Mistakes to Avoid

• Cutting everything at once. TSI should be done in phases over 2-3 years. Removing too much canopy at once causes a flush of invasive species that overwhelms native regeneration. Aim to remove 30-40% of the canopy in the first pass.
• Skipping the forester. At minimum, walk your property with your county extension forester (free service in most states) before you start. They will spot high-value trees you might miss and flag species you should not touch.
• Treating in spring. Sap is rising and pushes herbicide out of hack-and-squirt cuts. Wait until late summer or fall for chemical treatments.
• Forgetting to mark treated trees. In a dense stand, you will lose track. Mark every treated tree with spray paint. It also helps you see your progress, which keeps motivation up.
• Ignoring invasives. If you have bush honeysuckle or autumn olive, kill those BEFORE doing TSI on native trees. Invasives will fill any gap you create faster than native species will. Get them out first, then open the canopy.

Frequently Asked Questions

What is timber stand improvement (TSI)?

Timber stand improvement is the selective removal of low-value, damaged, or undesirable trees to give your best trees more sunlight, water, and nutrients. Common methods include hinge cutting, girdling, and hack-and-squirt herbicide injection. TSI improves timber value, wildlife habitat, and property aesthetics simultaneously.

When is the best time to do TSI work?

Late summer through mid-fall (August through October) is the best window for hack-and-squirt and girdling because the tree is actively transporting sap and will pull herbicide into the root system. Hinge cutting for bedding cover is best done in late winter (January through March) when you can see the timber structure without foliage and are not disturbing nesting wildlife.

Which trees should I remove during TSI?

Target low-value and invasive species first: box elder, elm, ash (especially dead or dying from emerald ash borer), honey locust, and invasives like bush honeysuckle and autumn olive. Keep high-value hardwoods like white oak, red oak, black walnut, black cherry, and sugar maple. When in doubt, keep it and consult a forester.

How much does timber stand improvement cost?

DIY timber stand improvement costs roughly $50 to $150 per acre in herbicide and supplies. A hatchet, squirt bottles, and a gallon of Garlon 4 Ultra triclopyr herbicide will treat several acres. Professional TSI services run $150 to $400 per acre depending on stem density and terrain. The USDA NRCS EQIP program may cost-share up to 75% of TSI expenses for qualifying landowners.

How long does it take to see results from TSI?

Treated trees typically die within one growing season. You will see increased sunlight on the forest floor within months. Native ground cover and browse species start filling in by the second growing season. Noticeable improvement in remaining tree growth takes 3 to 5 years. Full canopy response and significant timber value increase takes 10 to 15 years.