FERNDALE, Wash. — At age 94, Mary Helen Cagey, an elder of the Lummi Indian tribe, has seen a lot of yesterdays. Some are ripe for fond reminiscence, like the herring that used to run rich in the waters here in the nation’s upper-left margin, near the border with Canada. Others are best left in the past, she said, like coal.

“I used to travel into Bellingham and buy my sack of coal,” she said, standing in sensible shoes on a pebbled beach at a recent tribal news conference, talking about her girlhood of rural subsistence and occasional trips to the nearby market town. The idea that coal producers would make a comeback bid, with a huge export shipping terminal proposed at a site where she once fished, called Cherry Point, is simply wrong, she said. “It’s something that should not come about,” Ms. Cagey said.

Many environmental groups and green-minded politicians in the Pacific Northwest are already on record as opposing a wave of export terminals proposed from here to the south-central coast of Oregon, aiming to ship coal to Asia. But in recent weeks, Indian tribes have been linking arms as well, citing possible injury to fishing rights and religious and sacred sites if the coal should spill or the dust from its trains and barges should waft too thick.

And as history has demonstrated over and over, especially in this part of the nation, from protecting fish habitats to removing dams, a tribal-environmental alliance goes far beyond good public relations. The cultural claims and treaty rights that tribes can wield — older and materially different, Indian law experts say, than any argument that the Sierra Club or its allies might muster about federal air quality rules or environmental review — add a complicated plank of discussion that courts and regulators have found hard to ignore.