The sugarcane plantations started taking over the islands' landscapes almost 150 years ago, when the Civil War cut off sugar supplies from the south. In the 1870s, the U.S. signed a "reciprocity treaty" with the Kingdom of Hawaii. The United States agreed to cut tariffs on Hawaiian sugar and rice, in exchange for Hawaii cutting tariffs on imported cotton and other American products. The spread of sugarcane plantations on the islands brought immigrant labor in waves from China, Japan and the Philippines. A smaller number of people also came from Portugal, Puerto Rico, Scotland and Germany. That immigration laid the foundation for the multicultural population of today's Hawaii.