PORTLAND, Ore. – The Cascade-Siskiyou National Monument in southern Oregon may shrink, following the recommendation of Interior Secretary Ryan Zinke.

The White House has not released a memorandum outlying Zinke’s recommendations about national monument changes, but the Washington Post and the Wall Street Journal obtained a copy of the 19-page report.

More: Zinke recommends altering several national monuments

Oregon’s sprawling national monument covers 112,000 acres along the California border. When he was president, Barrack Obama expanded the monument by 48,000 acres to protect biodiversity.

Timber companies criticized the change and said it restricted timber supply in the area.

The Washington Post reports that Zinke recommended shrinking four monuments: Bear Ears and Grand Staircase-Escalante in Utah, Gold Butte in Nevada, and Cascade-Siskiyou. Zinke reportedly also recommended altering several other sites.

Zinke said the recommended changes will enhance economic activity on the land. He visited the Oregon monument in July as part of his review.

Zinke only reviewed monuments created since 1996 that were larger than 100,000 acres, per President Donald Trump's executive order.

Rarely do presidential administrations propose shrinking monuments under the Antiquities Act of 1906. Historically, presidents generally use the act to protect areas of historical and natural significance.

The White House has final say on whether to approve Zinke’s recommendations. Trump has previously expressed concern with more recent national monument designations, and called the designation of some monuments an overreach of the Antiquities Act.

Oregon Governor Kate Brown has said she may sue if Trump decides to shrink the Cascade-Siskiyou. She released a statement in August, calling on the federal government to preserve the monument.

"Oregonians have a proud tradition of environmental stewardship, and any scale-back of the Cascade-Siskiyou National Monument could have devastating impacts on health of the old-growth forest lands and incredible array of species that rely on the land's habitats," Brown said. "In the face of new threats to Oregon's public lands and our natural resources, I call on Attorney General Ellen Rosenblum to consider all legal options necessary to defend our Oregon values, and to be ready to challenge any overreach of executive power."

Background: Trump administration adds Oregon’s Cascade-Siskiyou to list of monuments under review

Oregon might sue if Trump shrinks national monument

US interior secretary to visit Oregon’s Cascade-Siskiyou monument