All engine-powered brush chippers operated in California must comply with California Air Resources Board (CARB) regulations, but which specific program applies depends on the engine type and horsepower. Registration is handled through the Portable Equipment Registration Program (PERP) or the Off-Road Diesel Vehicle regulations.
For gasoline brush chippers
Gasoline-powered brush chippers are regulated under the Small Off-Road Engine (SORE) program, but they do not need to be registered individually with CARB.
- Engine size: SORE regulations cover spark-ignition engines 25 horsepower or less. Chippers with engines over 25 horsepower (19 kW) are not classified as small off-road engines (SORE) and are exempt from the SORE program.
- Compliance for new models: Starting in 2024, most new SORE equipment sold in California must be zero-emission. Gasoline chippers manufactured before this date can continue to be sold and used.
- Owner responsibility: There is no registration requirement for owners of SORE equipment. The regulations focus on manufacturers to ensure the engines are certified for sale in California.
For diesel brush chippers over 50 horsepower
For those requiring diesel-powered brush chippers over 50 horsepower, they must be registered under CARB’s Portable Equipment Registration Program (PERP) or be permitted by a local air district.
- PERP is voluntary: PERP is a statewide program that allows owners to register their portable equipment once with CARB, rather than having to get separate permits from each local air district they operate in.
- Dual registration: If you use PERP, the engine and the chipper unit itself must be registered separately. The engine is registered for combustion emissions, while the chipping unit is registered for particulate matter emissions.
- Local air district alternative: You can choose to get permits from each local air district where you operate instead of using PERP.
- Emission standards: Portable diesel engines are subject to strict emission standards. For a unit to be eligible for PERP registration, its engine must satisfy specific emission limitations, typically requiring it to be a Final Tier 4 engine.
For diesel brush chippers under 50 horsepower
As you can see above, chippers with engines under 50 HP are not subject to California’s CARB regulation. Having a chipper under 50HP doesn’t mean you’ll be stuck with a powerless machine. In fact, the BVR 10 model by Morbark, for example, has an incredibly powerful, 48HP Deutz diesel engine package option that’ll chew through 8″ to 10″ material all day long – with the occasional 12″ diameter log. It’s perfect for utility line clearing, residential tree care, rental yards, municipalities and more.
Morbark BVR 10 : 48HP-74HP Deutz Diesel or 74HP Gasoline Engine Packages
For self-propelled diesel brush chippers
Self-propelled chippers with a diesel engine are subject to the In-Use Off-Road Diesel Vehicle Regulation and must be reported in the Diesel Off-Road Online Reporting System (DOORS), not PERP.
Next steps
- If you own a diesel chipper (over 50 hp): Determine if you want to register it under PERP for statewide use or get permits from your local air district. Review CARB’s PERP requirements and confirm your engine meets the necessary emissions standards.
- If you own a small gasoline chipper: No registration with CARB is required for your equipment. Check for a label that indicates it is certified for sale in California, especially if it was purchased after 2024.
- If you own a self-propelled diesel chipper: Report it in CARB’s DOORS system and comply with the Off-Road Diesel Vehicle Regulation.
Want more information? View/ download this 31-page “Portable Equipment Frequently Asked Questions” PDF provided by the California Air Resources Board.
