(CNN) About six months before President Donald Trump cut the monument's size nearly in half, land management officials described Grand Staircase-Escalante National Monument as a boon for tourism, science and historic preservation, newly released documents show.

Based on outside research, "it is reasonable to conclude that visitation would be less if the lands had not been designated as a monument," officials with the Interior Department's Bureau of Land Management wrote in a May 2017 memo. They also warned that "more vandalism would have likely occurred without Monument designation," and that one region of the monument "contains a plethora of paleontological specimens: twelve new dinosaur species have been discovered since designation."

The memos and emails show the inner workings of the team assisting Interior Secretary Ryan Zinke with the monument review, which resulted in Trump's December decision to cut Grand Staircase by nearly 45% and Bears Ears National Monument by more than 80%. The documents were first reported on Monday by The Washington Post.

The documents also show an official leading the review effort eliminating language from a document he believed "undercuts the case."

The decision on Grand Staircase and Bears Ears balanced "wanting to protect these objects of historic or scientific interest while ensuring public access to public land," Zinke wrote at the time in a CNN.com op-ed.

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