Education

Woods, invasives, and wildfire in Brown County.

Five short reads on why the understory locks up, how mulching and follow-up chemistry work, what timber stand improvement actually does, and why southern Indiana homeowners now look up wildfire risk.

Section 01

Why invasive species are a property problem

Invasives are not just weeds. In Indiana woodlands they take the understory, change the soil, and starve the next generation of oak and hickory. Once a stand is closed in, you lose access, timber, wildlife cover, and the groundcover that holds soil on a slope.

Brown County sits in unglaciated southern Indiana hills. Fence rows, hollows, and oak-hickory ridges are the exact places bush honeysuckle, autumn olive, and multiflora rose do their best work. The same pattern shows up across the state, and on most private acres the first sign is simple: you cannot walk the woods you used to walk.

Honeysuckle and multiflora rose filling an oak woodland understory — Closed understory

The same kind of oak woods after forestry mulching — Opened stand

Species that dominate Brown County and Indiana woods

Bush honeysuckle

Amur, Morrow, and Bell’s honeysuckle form a wall of shrubs. Indiana DNR notes they shade the forest floor so hard that little remains but bare dirt.

Multiflora rose

Planted for livestock fence and erosion control. Now one of the most widespread invasives in the state. Thorny thickets lock up fence lines and woods.

Autumn olive

Nitrogen-fixing shrub that changes soil chemistry and crowds out natives in old fields, roadsides, and woodland edges.

Callery pear, tree of heaven, privet

Bradford pear, Ailanthus, and privet fill gaps after disturbance. Japanese honeysuckle, garlic mustard, and stiltgrass take the ground layer.

Native plants, wildlife, and soil

Oak, hickory, and native wildflowers need light at the forest floor. A honeysuckle layer cuts that light and, in some species, adds chemicals that suppress other plants. Seedlings fail. The stand looks wooded from the ridge, and empty underneath.

Wildlife follows the plants. Fewer native insects, fewer nesting sites, and a berry crop that feeds birds in fall then spreads the next wave of invasives. Deer concentrate browse on the native stems that are left. What looks like “cover” is often a trap for the habitat you wanted.

Soil is the piece most people miss. When the native groundcover is gone, rain hits bare dirt. On Brown County slopes that means sheet erosion, washed-out trails, and silt in the creek. Multiflora rose was even promoted as an erosion planting, then became the problem it was supposed to solve. A mulch layer after mechanical work is the opposite: it covers the soil while the stand opens.

Light

Understory shade

Invasives capture the sun before oak seedlings can.

Food

Wildlife gap

Native insects and cover decline as the shrub layer takes over.

Soil

Bare ground

Lost groundcover on steep hills speeds erosion into the hollows.

Section 02

How we combat it: mulch first, then chemistry

Cutting honeysuckle and walking away is a one-year job. The stumps resprout. Purdue’s work on Amur honeysuckle in Indiana mixed-hardwood forests is blunt about this: forestry mulching is a strong way to knock the shrub layer down at scale, and follow-up control is still required to kill resprouts and new seedlings.

That is the job we sell. Mechanical mastication opens the stand. Safe, targeted chemical follow-up keeps it open. One crew, one plan, not a mulcher in year one and a guess in year two.

01
Walk the acres
Species, slope, timber, access, and what you want the land to do.
02
Mulch in place
The forestry mulcher grinds shrubs and ladder fuels. Material stays as a soil cover.
03
Treat what remains
Cut-stump or follow-up foliar work on resprouts, matched to species and season.
04
Come back
A second look in the next growing season so the reclaim sticks.

Mechanical

Forestry mulching

Fast on thicket. No burn pile. Soil stays covered. Purdue researchers at the Department of Forestry and Natural Resources found mulching heads a promising way to accelerate invasive shrub control in Indiana hardwoods, especially when the head works the stump with enough intensity to limit sprouting.

Follow-up

Targeted chemistry

The same Purdue work is clear that mulching alone is not the finish. Resprouts and seedlings need a later treatment. Foliar work a season after mulching is a standard path for invasive shrubs. We apply it as follow-up, not as a broadcast spray of the whole woods.

Source: Frank, Saunders, and Jenkins, Purdue University / Hardwood Tree Improvement and Regeneration Center. Short-term vegetation responses to invasive shrub control for Amur honeysuckle in Indiana mixed-hardwood forests (Forests, 2018). Related thesis work concludes both mulching and cut-stump “will require follow-up control methods to kill resprouting shrubs and new seedlings.”

We are the one-stop shop for that sequence. Landowners should not have to hire a mulcher, then hunt for someone willing to treat resprouts. If the acres need both, we scope both.

Plan the full sequence

Section 03

Timber stand improvement, in plain terms

Timber stand improvement (TSI) is work that tilts a woods toward the trees you want. In southern Indiana that usually means oak and hickory, not a thicket of invasives and poorly formed stems.

First the invasives come out. Then competing brush and low-value stems that steal light and water. Crop trees get the growing space. Native timber can put on wood without fighting a shrub layer that never belonged here.

Oak-hickory stand after understory reduction

Remove the invasive understory so oak seedlings see the sky.
Release crop trees: keep the oaks and hickories that can make a stand.
Cut or mulch poorly formed, damaged, or off-site stems that will never be timber.
Leave a woods you can walk, hunt, and pass on, not a wall of honeysuckle.

What changes

Light at the forest floor

BeforeBlocked

AfterOpen to crop trees

Growing space

BeforeShared with shrubs

AfterHeld by oak and hickory

Access

BeforeThicket

AfterWalkable understory

Next stand

BeforeInvasive seedlings

AfterNative regeneration has a chance

Section 04

Why wildfire is on the list in southern Indiana

Most Hoosiers still think of wildfire as a western problem. In southern Indiana a large share of homes already sit in the wildland-urban interface: houses mixed with or next to woods, brush, and leaf litter. SILVIS Lab’s 2020 WUI maps put about 39 percent of housing units in a south-central Indiana county set in that interface. In Brown County the figure is 94 percent of housing units. Statewide Indiana is closer to 11 percent. This county is woods with houses in them, not a town with a woods nearby.

That is why WUI wildfire is a homeowner problem here. Embers travel ahead of the flame front. Ladder fuels (honeysuckle, privet, low brush) let a ground fire climb. Ridge roads and hollows slow access. Volunteer departments cover big acres. A home that looks “in the trees” is the exposure: ignition of the structure, loss of access, smoke, and a fire that does not wait for a hydrant.

First Street’s wildfire model scores every property for 30-year exposure to direct fire or embers, including a hotter, drier climate. For Brown County their published county counts put wildfire risk on about 18 percent of residential properties now (2,402 of 13,408), rising to about 43 percent in the 30-year outlook (5,756). Across all property types they show about 3,000 at risk today of roughly 15,100 parcels. First Street also notes that a large share of new wildfire exposure over the next three decades is in forested land east of the Mississippi.

The hills themselves add to that. Unglaciated southern Indiana is ridges, steep south and west faces, and tight hollows. Fire, wind, and embers run upslope. Oak-hickory litter and an invasive understory give it something to climb. That is not the flat till plain north of Indianapolis.

94%

of Brown County housing units are in the wildland-urban interface (SILVIS Lab, 2020).

18%

of Brown County residential properties have First Street wildfire risk now (2,402 of 13,408).

43%

in First Street’s 30-year outlook for those same residential properties (5,756).

First Street · Brown CountyLook up your home’s Fire Factor.Open First Street’s Brown County wildfire map. Search an address for 30-year fire and ember risk on that property — 18% of homes here now, 43% in their 30-year outlook.Open the map

Section 05

How defensible space protects the home

Defensible space is the cleared, managed ground around a home, cabin, or barn. It does two jobs. It lowers the chance flame reaches the walls, and it gives firefighters a place to work. In our woods that means gravel against the structure, forestry mulching through the first thirty feet, and thinned oak woodland beyond.

Ladder fuels (honeysuckle, privet, low brush) let a ground fire climb into the canopy. Mastication converts those fuels to surface mulch. Embers can still land. What they land on matters: rock and gravel at 0 to 5 feet, not stacked firewood and dry shrubs against the siding.

STRAKER

Fire & Forestry

Southern Indiana WUI

Defensible space for homes

Homes on oak-hickory ridges sit in the wildland-urban interface. We build the zones with the mulcher: gravel at the structure, thirty feet of fuel conversion, then thinned woods beyond.

0–5 ftImmediate zoneNoncombustible gravel or rock against the structure. No mulch, brush, or firewood against the walls.
5–30 ftFuel reductionForestry mulching converts ladder fuels to surface fuels and mulch. Open the understory so fire has less to climb.
30–100 ftExtended woodlandThin brush and keep spacing in the oak-hickory stand. Crop trees stay. This is the southern Indiana WUI edge.

0–5 ft: noncombustible. Gravel or rock. Nothing stacked against the building.
5–30 ft: fuel reduction. Mulch the brush. Keep mature trees, lose the ladder.
30–100 ft: extended woodland. Space and thin so a fire in the woods has less continuity.

This is mechanical work. We do not light burns. The same mulcher that opens a honeysuckle stand can cut the zones around a structure. If you have already looked up a First Street Fire Factor on a Brown County ridge lot, this is the on-the-ground answer.

Plan defensible space