Michigan officials are inviting public comment on proposed changes to a quarantine intended to protect walnut trees from a killer fungus.
The order involves Thousand Cankers Disease, which is found in more than a dozen states. The fungus is carried by beetles and prevents trees from getting proper nutrition.
The quarantine generally prohibits shipment of walnut nursery stock, certain timber products and hardwood firewood into Michigan from infested states.
Exempt are walnut furniture, veneer, kiln dried walnut lumber without bark and walnut nuts and nutmeats.
Gina Alessandri of the Department of Agriculture and Rural Development says Michigan's forests have more than 8 million black walnuts.
The revised quarantine includes an updated list of regulated areas and a new treatment provision for walnut timber products with bark attached.