The Ifugao Rice Terraces illustrate the remarkable ability of human culture to adapt to new social and climate pressures as well as to implement and develop new ideas and technologies. Although listed by the UNESCO as a World Heritage site believed to be older than 2,000 years, there are some conflicting recent studies that report they may be less than 1,000 years old.
Maintenance of the living rice terraces reflects a primarily cooperative approach of the whole community which is based on detailed knowledge of the rich diversity of biological resources existing in the Ifugao agro-ecosystem, a finely tuned annual system respecting lunar cycles, zoning and planning, extensive soil conservation, and mastery of a complex pest control regime based on the processing of a variety of herbs, accompanied by religious rituals.
The rice terraces of the Cordilleras are one of the few monuments in the Philippines that show no evidence of having been influenced by colonial cultures. Owing to the difficult terrain, the Cordillera tribes are among the few peoples of the Philippines who have successfully resisted any foreign domination and have preserved their authentic tribal culture. The history of the terraces is intertwined with that of its people, their culture, and their traditional practices.
Apart from the idjang stone-fortresses of the Ivatan of the Batanes, the terraces, which spread over five present-day provinces, are the only other only form of surviving stone construction from the pre-colonial period. The Philippines alone among south-east Asian cultures is a largely wood-based one: unlike Cambodia, Indonesia, or Thailand, for example, in the Philippines both domestic buildings and ritual structures such as temples and shrines were all built in wood, a tradition that has survived in the terrace hamlets.
It is believed that terracing began in the Cordilleras less than one thousand years ago as taro cultivation. It is evidence of a high level of knowledge of structural and hydraulic engineering on the part of the Ifugao builders. The knowledge and practices, supported by rituals, involved in maintaining the terraces are transferred orally from generation to generation, without written records. Taro was later replaced by rice around 1600 A.D. which is the predominant crop today.