[7] Puerto Rico became a territory of the United States in the aftermath of the Spanish-American War in 1898 and, in 1903, President Theodore Roosevelt set aside these former timberlands to proclaim the Luquillo Forest Reserve, the first ecologically protected area in the island.[8] Meanwhile, on the state level, colonial governor Arthur Yager set aside mangrove forests along the coasts of Puerto Rico for their ecological value between 1918 and 1919: Aguirre,[9] Boquerón,[10] Ceiba,[11] and Guánica.[14] By 1935 all the newly protected woodlands of Puerto Rico under were consolidated as part of the Caribbean National Forest, which was then divided into the areas of the Sierra de Luquillo (El Yunque) and the Cordillera Central (Guilarte and Toro Negro).[14][15] In addition to their natural resources these areas were also managed as tourist attractions, something that is evident in the territory-wide construction projects of visitor infrastructure by the Civilian Conservation Corps during the 1930s Roosevelt presidency.[18] It was during this time that the ownership of the western portions of the Caribbean National Forest passed to the territorial government, creating Toro Negro in 1934 and Guilarte, which was separated from the latter, in 1935.