At the moment, the only sensible public "forest land" in the Philippines that I can think of are those in:
(a) Sierra Madre mountain range, northern Quezon-Aurora-eastern Cagayan & Isabela provinces, fronting the Pacific Ocean.
Sierra madre's western side, ie western Cagayan-Isabela-N.Vizcaya-N.Ecija-Bulacan-Rizal-southern Quezon provinces are generally deforested, converted to rice land, corn land, other agri lands, human settlements.
(b) Palawan, especially north of Puerto Princesa up to Busuanga.
(c) Cordillera, Mountain Province especially. Abra, Benguet, and Ifugao are highly deforested, large tracts of previously forest land converted to rice land (the famous rice terraces), vegetable land (baguio beans, carrots, cabbage, etc.).
(d) Zambales mountain range, especially north-east of Subic and Olongapo.
(e) Mindoro, especially the mountain areas (Mt. Halcon, other neighboring mojuntains)
(f) Romblon's Sibuyan island, especially around Mt. Guiting-guiting.
(g) Certain areas of Mindanao, like surrounding Mt. Apo, Mt. Kitanglad, Mt. Matutum, etc.
(h) Pockets of forested areas in other provinces like around Mt. Arayat ni Pampanga, Mt. Makiling in Laguna, Mt. Banahaw in Quezon, Mt. Canlaon in Negros, Cebu south of cebu city, etc.
Most of the other "public forest land" is either upland rice area, volcanoes, brushland, marginal forest land and grassland. And sadly, these areas comprise the majority of the public forest land.
Currently, these areas contain almost zero logging companies, but hundreds of thousands of poor households. I would say that almost 100% of current forest destruction and denudation is caused by poaching, logging, and slash-and-burn by poor households from the agri lowlands, to upland settlers. You can include military loggers sometimes, in military reservation areas and neighboring mountains to their military camps. Like Camp Magsaysay in Laur, N. Ecija.
The “tragedy of the commons” is at work here. Majority of those forest poachers, loggers and slash-and-burn farmers are in the thinking that “if I don’t cut this thigh-big tree now and wait for it to become bigger, someone else will cut this tomorrow or next week, so I better cut it now.” A resource like a “public forest” that is owned by everyone and no one in particular can unleash the energy of race to mass destruction.
Privatizing some public forest land, assuming it can be done when the next round of Constitutional change happens, is possible. The demand for industrial trees, cash and food crops, from bananas to mangos to pineapple to palms, as well as crops for bio-diesel and agri-petroleum, will keep increasing. These crops you cannot plant inside greehouses and via hydroponics. You need vast tracts of open land with lots of sunlight to grow these crops well.
Maybe we can start from there, the degraded, denuded, and turned-grassland "public forest land". Government has no real interest, much less incentive, to conserve and develop these lands back to real forest land. The first thing that the DENR and LGUs will ask if we expect them to do this is, "can you give us more money?" Which means actually, "can you raise more taxes for this job?"