Posted: Jun 04, 2021 10:48 AM MT | Last Updated: June 4 Trans Mountain was ordered to halt tree clearing along the the pipeline right-of-way after the company says a subcontractor started work without completing its environmental requirements. (CBC) An order stopping tree cutting and grass mowing across the entire Trans Mountain pipeline expansion project was issued Thursday by the Canada Energy Regulator, the agency that enforces safety and environmental guidelines for pipeline projects across Canada. A statement released by the CER said it issued the order to immediately stop all clearing activity "to prevent harm to nesting birds in the pipeline project's right of way and to ensure Trans Mountain is correcting any issues it has in relation to contractor oversight and management."