Southbound Highway 101 will be down to one lane each morning this weekend in northern Marin County as Caltrans trims elm trees along the road.

The lane will be closed 5:30 to 9 a.m. Saturday and 5:30 to 9:30 a.m. Sunday between the Redwood Landfill interchange and the entrance to Olompali State Historic Park.

Caltrans spokesman Robert Haus said in a statement that crews would be cutting dead and diseased tree limbs.

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