Under recommendations sent by Interior Secretary Ryan Zinke to President Donald Trump, six national monuments would be reduced in size, with millions of acres of protected lands opened to grazing, logging and oil and gas exploration, but Southern California’s monuments may be spared.

Zinke did not offer changes to two local monuments: The San Gabriel Mountains National Monument, a 346,177-acre swath of the Angeles National Forest from Santa Clarita to Mt. Baldy, and the Mojave Trails National Monument, a 1.6 million-acre desert landscape that bridges the area between Joshua Tree National Park and Mojave National Preserve.

In the memo, Zinke did not spell out reasons why no changes were listed for those two monuments. The memo, a draft report from the secretary responding to an executive order calling for review of 27 national monuments established by previous presidents, was obtained by the Washington Post on Sunday and the Associated Press on Monday.

The White House told the Post it will not comment on leaked information.

But Daniel Rossman, acting California director for The Wilderness Society and a participant in getting the San Gabriel Mountains monument established nearly three years ago by President Barack Obama, said the local monument is not out of the woods.

“I would issue caution to anyone that says we are off the hook,” Rossman said. “This could mean they will try to impact the management plan of the San Gabriel Mountains monument, which is concerning,” he said on Monday.

In June, Rep. Paul Cook, R-Yucca Valley, had asked the Trump administration to shrink the boundaries of the San Gabriel Mountains monument.

The Sand to Snow National Monument, 154,000 acres in San Bernardino County that provides key wildlife corridors near Joshua Tree National Park, was removed from the review by Zinke last month.

The remaining monuments in California still part of the presidential review are:

Giant Sequoia National Monument, which protects 33 groves of ancient sequoias — some of the world’s largest trees — across 328,000 acres of national forest land in the Sierra Nevada west of Visalia.

Carrizo Plain National Monument, a 246,000-acre area owned by the U.S. Bureau of Land Management east of San Luis Obispo that is famous for carpets of wildflowers and that contains the largest native grassland remaining in California.

Berryessa Snow Mountain National Monument, 331,000 federal acres between Mendocino County to Napa County known for bald eagles, black bears, rare plants and Indian history.

“These are places that speak to our values, and have been enjoyed by all Americans,” said Theresa Pierno, president of the National Parks Conservation Association.

National monuments are federal areas — usually owned by the U.S. Forest Service, Bureau of Land Management, Fish and Wildlife Service or National Park Service — where presidents use their executive authority to provide protections, including bans on oil and gas drilling, mining, grazing and off-road vehicle use. Some of them are eventually turned into national parks by Congress.

Zinke’s recommendations to pare down four Western monuments — and allow more logging and other development in three other monuments — “represent an unprecedented assault on our parks and public lands” by the Trump administration, said Jamie Williams, president of the Wilderness Society.

It was not clear from the memo how much energy development would be allowed on the sites recommended for changes, although the memo cites “active timber management” as a goal, as well as increased public access.

A law signed in 1906 by President Theodore Roosevelt, called the Antiquities Act, gives presidents the authority to establish national monuments without a vote of Congress, something that nearly every president has done since then. But in recent years, rural Republicans have argued that the law has been abused, and rather than protect archaeological sites, has been a potent tool to block logging, mining, oil drilling and cattle grazing on some public lands, and commercial fishing in some ocean areas.

In April, slamming what he called “a massive federal land grab,” Trump signed an executive order directing Zinke to review all national monuments that were established since 1996 and are larger than 100,000 acres. The national monuments marked in Zinke’s report for reduction:

Grand Staircase-Escalante National Monument, a 1.9 million-acre area that was established in Utah by President Bill Clinton in 1996 and whose protection killed a proposed coal mine.

Bear’s Ears, a 1.3 million-acre monument in southeastern Utah designated by President Barack Obama last year.

Gold Butte, a 296,000-acre site north of Las Vegas that is known for bighorn sheep, desert tortoises and a ghost town.

And Cascade-Siskiyou, an 86,000-acre monument in Oregon that was established by Clinton and doubled in size by Obama in January. Cascade-Siskiyou is mostly in southern Oregon, on national forest and BLM land near Ashland, but about 5,000 acres extends into Siskiyou County, California.

Zinke’s memo also recommended that Trump reduce two ocean monuments in size: Pacific Remote Islands, a vast area southeast of Hawaii that includes Wake Island and Johnston Atoll, and Rose Atoll, west of American Samoa. Both were set aside for protection by President George W. Bush.

Staff writer Steve Scauzillo contributed to this article.