Illegal as well as legal logging in NSMNP has been, since decades, a serious threat to forests and people. Commercial logging in the NSMNP exacerbated in the 1980s, and was partly stopped due to a logging ban under the Aquino administration (1986-1992) as well as due to heavy attacks from the New People’s Army (NPA) during the 1990s, claiming ‘revolutionary taxes’. Large-scale illegal logging has continued at least since the 1980’s logging boom, and was placed on the top of the political agenda in 2000, when President Estrada established an anti-organized crime commission to investigate illegal logging [1].

Illegal logging in NSMNP operates as a highly organized network, involving many different actors, such as financiers that advance cash for fuel and supply, local village officials supporting their activities, and small logging teams, who have their own illegal local “area-area” concessions system, sometimes marked with signposts. Forest guards are bribed by logging teams, as well as police and military checkpoints on the transport way to the urban centers. It was estimated that annual payments to officials of the Department of Environment and Natural Resources (DENR) in San Isabela amounted to 160,000 to 280,000 USD). DENR officials often downplay the scale of corruption, claiming the need to ‘humanize’ the law so that poor people can meet their needs. However, in fact large benefits of illegal logging are appropriated by themselves and mainly by an organized business network, alleged to be related to seven businessmen of Isabela province. They are located in the urban centers, registered as timber traders and plantation owners, which enables them to legalize illegal logs. Also here, apparent differences between the amount of furniture produced and legal wood sources are solved by corruption [1].

While some locals, particularly young, are attracted by the well paid illegal activities, many others do complain about the irreversible impacts. Large deforestation was related to increased floods and calamities, in particular in 2008, during which four typhoons claimed the lives of 100 people in Isabela and Cagayan province. Biodiversity loss is inevitable. Farmers complain that heavy trucks destroy access ways. Fish catches have declined due to erosion and river siltation, and indigenous worry about disturbed wildlife and degraded forest resources. Women report to be constantly harassed by illegal loggers, who spend much of the earned money on alcohol, tobacco and prostitution [1].

Resistance has taken several forms, starting with campaigns and street protests against illegal logging. A few legal cases were filed against logging middlemen; however they were either settled or dismissed, due to the deep political entrenchment of the network into local politics. In 2008, pressured by church and environmental groups, the governor of Isabela province set up the Anti-Illegal Logging Task Force, partly motivated to avoid financing of the political opposition through illegal logging revenues. In the following years, more cases were filed, DENR officials were replaced and illegal equipment and supply, such as chainsaws and timber, was seized. However, anti-logging activists are facing strong repression. Among the likely motives of the killing of Mayor Francisco Talosig in 2009, a former forester from Maconacon, has been his strong stand against illegal logging [2].

As of 2015, illegal logging in the Northern Sierra Madre National Park continues to be a threat to communities and primary ecosystems [3].

According to a field study [1], 11 logging hotspots were identified in the Northern Sierra Madre Natural Park in 2007. These are located in 1) Pinacanauan de San Pablo (Tuba), 2.) Puerta (Dy Abra, Masipi East), 3.) Pinacanauan de Tumauini (Antagan), 4) Bintacan River (Batong Labang), 5) Abuan River (Cabeseria 27), 6) Catalangan River (Villa Miranda, San Isidro), 7) Disabungan River (Del Pilar), 8) Ilaguen River (Tappa, Ibujan), 9) Divilacan coast (Dilakit, Dimasalansan, Bicobian), 10)Palanan River (Dilacnadanom, Culasi), 11) Palanan Coast (Didadungan, Divinisa, Dimatatno).

The report [1] estimated that annual extraction in these 11 illegal logging sites during 2007 amounted to around 20,000 to 35,000 cubic meters, with a total market value of 238 million PHP to 393 million PHP. Missed forest taxes were estimated to amount to around 30 million PHP to 51 million PHP. Annual benefits for several illegal logging bosses were estimated to amount to a total of 42-200 million PHP (840,000 to 4,000,000 USD).

A Greenpeace report from 2006 [4] also reported on 9 spotted illegal logging sites, 3 of them overlapping with the previously mentioned report [1]; while mentioning other six sites: Dunoy lake, Dungsok lake, Kamalaklakan, Pagsungayan, Diwagao, and Diguse location.

No concrete information on the involved companies has been available. The Greenpeace report states as an example the Digna Abad Wood Products Company, one of the oldest furniture businesses based in IIagan City, Isabela Province [4].

It was estimated that around 3000 people from local villages are involved in the logging network of NSMNP, lead by organized an organized urban business network. Working in logging teams is among the most profitable local income generating activities [1].