Sierra Madre (Philippines)

The mountains as viewed near summit of the Mount Oriod in Bulacan

The range's highest point is unclear, and several peaks are attributed as the highest. Mount Anacuao in Aurora province stands at 6,069 feet (1,850 m), while Mount Cetaceo in Cagayan is of similar altitude. However, an expedition in September and October 2012 to Mount Guiwan (Nueva Vizcaya) preliminarily measured an altitude of 6,283 feet (1,915 m) on the summit.[4]

List of highest peaks along the mountain range by elevation.

• Mount Guiwan – 6,283 ft (1,915 m)
• Mount Mingan – 6,191 ft (1,887 m)
• Mount Anacuao – 6,869 ft (2,094 m)
• Mount Cetaceo – 5,981 ft (1,823 m)
• Mount Dos Cuernos – 5,856 ft (1,785 m)
• Salakot Peak – 5,699 ft (1,737 m)
• Mount Kiligantian – 5,490 ft (1,670 m)
• Mount Cresta – 5,062 ft (1,543 m)
• Mount San Cristobal – 4,882 ft (1,488 m)
• Mount Otunao – 4,803 ft (1,464 m)
• Mount Irid – 4,751 ft (1,448 m)
• Mount Batay – 4,596 ft (1,401 m)
• Mount Dos Hermanos – 4,557 ft (1,389 m)
• Mount Minalunad – 4,419 ft (1,347 m)
• Mount Oriod – 3,957 ft (1,206 m)
• Mount Palanan – 3,921 ft (1,195 m)
• Mount Cagua – 3,717 ft (1,133 m)
• Mount Etnora – 3,671 ft (1,119 m)
• Mount Lubog – 3,133 ft (955 m)
• Mount Sumag – 2,759 ft (841 m)
• Mount Batolusong 2,559 ft (780 m)
• Mount Mapalad 2,461 ft (750 m)
• Mount Daraitan – 2,425 ft (739 m)
• Mount Maynoba – 2,388 ft (728 m)
• Mount Masungki – 2,165 ft (660 m)
• Mount Binutasan – 1,844 ft (562 m)
• Mount Malauban – 1,024 ft (312 m)

List of major rivers along the mountain range by length.

• Cagayan River 518 km (322 miles)
• Pampanga River 270 km (167.7 miles)
• Ilagan River 189 km (117 miles)
• Angat River 153 km ( 95 miles )
• Agos River 93.8 km ( 58.2 miles )
• Pinacanauan River 82.6 km (51.3 mi)
• Umiray River 80.6 km (50 miles)
• Palanan River 79 km (49 miles)
• Marikina River 78 km (48.2 miles)
• Abuan River 70 km (43.4 miles)
• Aguang River 52 km (32.3 miles)
• Kaliwa River 31.3 km (19.4 miles)

• Daranak Falls, Tanay
• Eva Falls, Dona R. Trinidad
• Lucab Falls, Dona R. Trinidad
• Secret Falls, Dona R. Trinidad
• Talon Pari Falls, Dona R. Trinidad
• Talon Pedro Falls, Dona R. Trinidad
• 13th Falls, Dona R. Trinidad
• Verdivia Falls, Dona R. Trinidad
• Zamora Falls, Dona R. Trinidad

The mountains in Gabaldon

The mountains in Isabela as viewed from Barangay Diddadungan in the town of Palanan

Northern portion of the range

Two ecoregions cover the Sierra Madre. The Luzon rain forests cover the lower slopes of the range, and are characterized by dipterocarp trees. The Luzon montane rain forests cover the portions of the range above 1000 meters elevation, and are characterized by laurel forests of oak and laurel trees.

• Aurora Memorial National Park
• Biak-na-Bato National Park
• Fuyot Springs National Park

• Amro River Protected Landscape
• Angat Watershed Forest Reserve
• Casecnan Protected Landscape
• Dinadiawan River Protected Landscape
• La Mesa Watershed Reservation
• Magapit Protected Landscape
• Northern Sierra Madre Natural Park
• Pantabangan–Carranglan Watershed Forest Reserve
• Peñablanca Protected Landscape and Seascape
• Quezon Protected Landscape
• Quirino Protected Landscape
• Simbahan-Talagas Protected Landscape
• Talaytay Protected Landscape
• Upper Marikina River Basin Protected Landscape

• Cagua Volcano, an active volcano in Cagayan province that last erupted in 1907.

Some coastal communities east of the Sierra Madre Mountains, especially from Palanan, Isabela heading north to near the northernmost tip of mainland Cagayan, are remote and isolated with no roads connecting them to towns west of the mountain range. Towns like Palanan, Divilacan and Maconacon, Isabela can only be reached by plane from Cauayan City or a boat ride from Aurora province, south of Isabela or from Santa Ana, Cagayan, north of the province. Ilagan City – Divilacan road traversing the Sierra Madre mountain is about to be completed.[5]

Northern Sierra Madre Natural Park, the largest protected area in Sierra Madre range, is home to dipterocarp trees belonging to Hopea and Shorea family, orchids such as Dendrobium aclinia, the leguminous tree, Milletia longipes and a member of the citrus family, Swinglea glutinosa.[6]

In the forest, in April 2010, the endemic lizard species Northern Sierra Madre Forest monitor lizard – Varanus bitatawa (common name: Butikaw) was described to science, although the Aeta and Ilongot indigenous peoples have known and used it as a food source. The Northern Sierra Madre Forest monitor lizard is one of the three frugivorous lizards in the Varanidae family along with V. olivaceus and V. mabitang. All of the three frugivorous lizards are found only in the Philippines.[7]

Endemic mammals in Sierra Madre are the Sierra Madre shrew mouse and Sierra Madre forest mouse.[8]

Narra, the national tree of the Philippines, Almaciga, and Kamagong can be found in Sierra Madre range.[9]

Isabela oriole, Philippine Eagle, and Philippine Crocodile are critically endangered species that can be found in fragmented locations.[9]

The Sierra Madre mountain range forest habitat is threatened by human activities. Settlers living at the lower portions of the slopes generally are supported by work in logging and charcoal-making. Some portions of the forest cover are already second growth forest. Forest degradation of at least 1,400 hectares per year caused by illegal tree cutting, slash and burn farming, fuel-wood collection, illegal hunting, and residential expansion.[9]

A gold and copper mine in the municipality of Kasibu, Nueva Vizcaya has been operated by the OceanaGold Corporation based in Australia. The Didipo mine is a large-scale open-pit mine in a remote location, and local residents claim the company has severely damaged both the environment for miles around the site, and suppressed the long-standing farming economy.[10] Oceana contintinues to assert a right to operate despite expiration of its permit, and opposition by organized local residents, the Catholic Church, and worldwide environmental groups.[11]

The Kaliwa dam project through a project called "New Centennial Water Source" in Sitio Cablao, Brgy. Pagsangahan, General Nakar, Quezon / Sitio Queborosa, Brgy. Magsaysay, Infanta, Quezon is threatening the endangered species living in the sparse remaining forest of Sierra Madre and indigenous people's lives in that area.[12] This project replaced the Kaliwa Low Dam that did not materialize and under the new administration, Rodrigo Duterte approved the Chinese-funded proposal. Aside from the destruction of ecologically-important forests, the dam also faces controversy for fulfillment of financial requirement through a Chinese loan with 2.0% interest rate than Japanese loan with 1.25% interest rate.[13] The project continues to face strong opposition from the public yet the government is eager to continue.[14]

The Mabuwaya Foundation is a non-governmental organization that aims to protect and conserve the Philippine crocodiles and other endemic threatened species. They mainly works in the towns of Divilican and San Mariano in Isabela.[15][16]