Are wood pallets biodegradable?
Wood is biodegradable, but a pallet doesn't vanish quickly. In soil, untreated pallet wood lasts a few seasons. In a landfill, much of its carbon stays buried: EPA's WARM model credits landfilled dimensional lumber with −1.09 MTCO2E per short ton of carbon storage (Exhibit 12-15). That doesn't make landfilling better than reuse.
In a landfill
WARM's landfill factor for dimensional lumber nets 0.15 of methane and 0.02 of transport against 1.09 of stored carbon, giving −0.92 MTCO2E per short ton. Reuse is −1.66, so moving wood from landfill to reuse still lowers emissions (landfill carbon storage).
In soil and compost
Ground pallet wood breaks down faster than whole boards, which is why mulch needs topping up. WARM has no composting factor for dimensional lumber ('NA' in Exhibit 12-3), so we don't attach an emissions number to it.
Treated and painted wood
Paints and preservatives don't biodegrade with the wood and are why painted pallets stay out of mulch and bedding; see painted pallets.
Sources
- Documentation for Greenhouse Gas Emission and Energy Factors Used in WARM, Version 16: Construction Materials Chapters, ch. 12 Wood Products (EPA-530-R-23-020) U.S. EPA. Accessed October 27, 2026. Exhibits 12-3 (p. 12-3), 12-9, 12-13, 12-15 and 12-16 (p. 12-10).