Stump grinding in Forest Grove, Oregon

Before the grinder arrives in Forest Grove

Emerald ash borer is confirmed in Washington County, and the county is under the ODF and ODA quarantine. Raw ash wood, stump and roots included, stays inside the quarantine area. It can leave only as chips 1 inch or smaller, as kiln-dried debarked lumber, or after heating to a 160F core for 60 minutes with ODA permission. From April 1 to September 30, the beetle’s flight period, any load of ash debris has to be covered. Do not haul an ash stump out of the county to a yard or wood lot until you have checked emerald ash borer in Oregon.

Next, call 811. The cutter head works below grade, where gas, water, power and communication lines run, and the free Oregon locate request has to go in with the lead time shown in the card above. A stump sitting over a marked line gets ground shallow or left, not chased.

Grinding needs no city permit on its own; the permit belongs to the tree. Forest Grove requires one to remove a street tree in the right-of-way or parkway, a tree on the Register of Significant Trees, or a tree 6 inches in diameter or larger (Oregon white oak 3 inches) on developable land. If the stump is in the parkway, call Community Development at 503-992-3227 first; the city’s permit form page was unreachable when checked.

What stump grinding costs in Forest Grove

The modeled range below is priced by diameter at the cut, with a minimum charge for small stumps, so measure across the root flare, not the trunk. Ash is where Forest Grove jobs move: a crew that has to keep coarse grindings in the quarantine, or cover the load during the April to September flight period, spends more time per stump than one raking chips into a bed.

Access and depth are the other levers. A stump behind a fence, or one ground deep for a replant, takes extra passes. BLS puts the Portland-Vancouver-Hillsboro labor index at $35.04 an hour mean wage across 1,160 tree trimmer jobs; that is the wage behind the model, not a price (method).

Modeled at $4 to $6 per inch of diameter with a $150 minimum, rounded to $50. Modeled estimate, not quotes (method).

Source: BLS Occupational Employment and Wage Statistics, May 2025, SOC 37-3013. Checked 2026-10-02.

Grindings, wood and quarantines

A grinder turns the stump into a pile of chips and soil larger than the hole. For an ash stump that pile is the quarantine question: chips 1 inch or smaller may move, but coarser grindings and the root chunks the grinder throws are raw ash wood and stay on the property or inside the quarantine. Spreading them in your own beds is the simplest legal use.

Oak has its own rule. Mediterranean oak borer is confirmed in Washington County, though no quarantine applies. An infested oak should be cut, then chipped to 1 inch or burned on site, stump included, and cut oak firewood should not travel more than 10 miles. Report suspect oaks with photos to the Oregon Invasives Hotline.

Oregon DEQ sets burning rules here, and a green stump smolders more than it burns. Read yard debris burning rules in Oregon before lighting anything, and chip when either option is allowed.

Replanting the spot

Forest Grove is in USDA zone 8b, and 69% of Washington County’s NOAA storm reports land between November and February, with January the peak month. Wet winter ground ruts under a grinder, so late spring through early fall is the easy window. For an ash stump, that window overlaps the April 1 to September 30 flight period when loads must be covered; grinding an ash stump in late fall or winter skips that step.

Replant in fall or early spring. Fresh grindings draw nitrogen from the soil as they break down, so clear them from the hole and add topsoil before planting, and pick a species other than ash for the spot.

Hardiness zone 8b. Grinding vs full removal: which one you need.

Source: USDA Plant Hardiness Zone Map 2023 (OSU PRISM ZIP data). Checked 2026-10-02.

What to do next

Identify the stump first. If it was an ash, decide where the grindings go before the job: on site, inside the quarantine, or chipped to 1 inch or less if they leave. Then file the 811 request and confirm with Community Development whether the tree itself needed a permit.

The Forest Grove tree trimming page covers pruning permits and line clearances, and the Washington County page has the storm record. Check any operator with the Oregon tree service license lookup.

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