Magdalena Abakanowicz, a Polish sculptor who transformed sisal and burlap into brooding forms that evoked the weight of political oppression, the desperation of the individual and the sufferings of the natural world, died on Thursday in Warsaw. She was 86.

She died after a long illness, her husband, Jan Kosmowski, said.

Ms. Abakanowicz (pronounced ah-bah-kah-NO-vich), who once described her sculpture as “a search for organic mysteries,” first attracted critical attention in the 1960s with free-standing woven works made from sisal that she unraveled from discarded ships’ ropes and dyed.

These Abakans, as they became known, were monumental, some more than 15 feet tall, hollow at the core and fitted with slits and folds. Hanging from the ceiling, nearly touching the floor, they resembled shrouds, twisted tree trunks, cocoons or druid priests — strange forms summoned from the lower depths of the collective unconscious.

“Like all of Abakanowicz’s cycles, the ‘Abakans’ lead outward, away from what they might appear to represent, into psychology and history, toward fundamental links between human beings and nature that are always waiting to be recognized and explored by the imagination,” the critic Michael Brenson wrote in Art Journal in 1995.