For the purpose of preserving and consolidating timber stands along the western boundary of the Yosemite National Park the President of the United States is authorized, upon the joint recommendation of the Secretaries of Interior and Agriculture, to add to the Yosemite National Park, in the State of California, by Executive proclamation, section 1 and the north half of section 12, township 1 south, range 19 east, Mount Diablo meridian.