Geography of the Philippines the Philippines, the Sierra Madre, stretching from Quezon province in the south to Cagayan in the north. 80 percent of the mountain range is tropical rainforest, which is diminishing from rampant illegal logging activity. The range serves as the eastern wall of Luzon Island that protects inhabitants from tropical cyclones usually coming from the Pacific Ocean. The largest plain of the nation is situated in the Central Luzon region and produces most of the national rice supply, earning itself the nickname ""Rice Bowl of the Philippines"". The plains encompass the provinces of Bulacan, Nueva Ecija, Pampanga, Tarlac and Pangasinan. South
Geography of the Philippines of mountain ranges in this region is called "Zamboanga Cordilleras", with the highest elevation at Mount Dapi, which is high. The southern coastline is irregular, featuring two smaller peninsulas, the Sibuguey and Baganian, extending southward to the Moro Gulf. To the north of the Diwata Mountains at northeast Mindanao lie Siargao island and the Dinagat group of islands. Southwest of the Zamboanga Peninsula is the Sulu Archipelago, a chain of islands which comprise the smaller archipelago provinces of Basilan, Sulu, and Tawi-Tawi. The Philippines is divided into a hierarchy of local government units (LGUs) with the 81 provinces and 38