ISPM 15 is a phytosanitary standard for wood packaging materials set by the International Plant Protection Convention (IPPC), designed to prevent pests and diseases from spreading across borders via timber. For shipments to the EU, if solid wood pallets, wooden boxes, wood strips, or dunnage are used, these packaging materials must undergo approved treatment (most commonly heat treatment, code HT) and bear an IPPC mark. Plywood, particle board, oriented strand board, and plastic or paper pallets are exempt.
Full explanation and HS code list: https://patisco.com/zh/eu-check/ispm-15 Check which EU regulations apply to your HS codes: https://patisco.com/zh/eu-check