The decision under review recites the factual backdrop, as follows:

This is an application for registration of title to four (4) parcels of land located in Panan, Botolan, Zambales, more particularly described in the amended application filed by Celestina Naguiat on 29 December 1989 with the Regional Trial Court of Zambales, Branch 69. Applicant [herein respondent] alleges, inter alia, that she is the owner of the said parcels of land having acquired them by purchase from the LID Corporation which likewise acquired the same from Demetria Calderon, Josefina Moraga and Fausto Monje and their predecessors-in-interest who have been in possession thereof for more than thirty (30) years; and that to the best of her knowledge, said lots suffer no mortgage or encumbrance of whatever kind nor is there any person having any interest, legal or equitable, or in possession thereof.

On 29 June 1990, the Republic of the Philippines [herein petitioner]. . . filed an opposition to the application on the ground that neither the applicant nor her predecessors-in interest have been in open, continuous, exclusive and notorious possession and occupation of the lands in question since 12 June 1945 or prior thereto; that the muniments of title and tax payment receipts of applicant do not constitute competent and sufficient evidence of a bona-fide acquisition of the lands applied for or of his open, continuous, exclusive and notorious possession and occupation thereof in the concept of (an) owner; that the applicant's claim of ownership in fee simple on the basis of Spanish title or grant can no longer be availed of . . .; and that the parcels of land applied for are part of the public domain belonging to the Republic of the Philippines not subject to private appropriation.

On 15 October 1990, the lower court issued an order of general default as against the whole world, with the exception of the Office of the Solicitor General, and proceeded with the hearing of this registration case.

After she had presented and formally offered her evidence . . . applicant rested her case. The Solicitor General, thru the Provincial Prosecutor, interposed no objection to the admission of the exhibits. Later . . . the Provincial Prosecutor manifest (sic) that the Government had no evidence to adduce. ^[3]

In a decision^[4] dated September 30, 1991, the trial court rendered judgment for herein respondent Celestina Naguiat, adjudicating unto her the parcels of land in question and decreeing the registration thereof in her name, thus:

WHEREFORE, premises considered, this Court hereby adjudicates the parcels of land situated in Panan, Botolan, Zambales, appearing on Plan AP-03-003447 containing an area of 3,131 square meters, appearing on Plan AP-03-003446 containing an area of 15,322 containing an area of 15,387 square meters to herein applicant Celestina T. Naguiat, of legal age, Filipino citizen, married to Rommel Naguiat and a resident of Angeles City, Pampanga together with all the improvements existing thereon and orders and decrees registration in her name in accordance with Act No. 496, Commonwealth Act No. 14, [should be 141] as amended, and Presidential Decree No. 1529. This adjudication, however, is subject to the various easements/reservations provided for under pertinent laws, presidential decrees and/or presidential letters of instructions which should be annotated/ projected on the title to be issued. And once this decision becomes final, let the corresponding decree of registration be immediately issued. (Words in bracket added)

With its motion for reconsideration having been denied by the trial court, petitioner Republic went on appeal to the CA in CA-G.R. CV No. 37001.

As stated at the outset hereof, the CA, in the herein assailed decision of May 29, 1998, affirmed that of the trial court, to wit:

WHEREFORE, premises considered, the decision appealed from is hereby AFFIRMED.

SO ORDERED.

Hence, the Republic's present recourse on its basic submission that the CA's decision "is not in accordance with law, jurisprudence and the evidence, since respondent has not established with the required evidence her title in fee simple or imperfect title in respect of the subject lots which would warrant their registration under " (P.D. 1529 or Public Land Act (C.A.) 141." In particular, petitioner Republic faults the appellate court on its finding respecting the length of respondent's occupation of the property subject of her application for registration and for not considering the fact that she has not established that the lands in question have been declassified from forest or timber zone to alienable and disposable property.

Public forest lands or forest reserves, unless declassified and released by positive act of the Government so that they may form part of the disposable agricultural lands of the public domain, are not capable of private appropriation.^[5] As to these assets, the rules on confirmation of imperfect title do not apply.^[6] Given this postulate, the principal issue to be addressed turns on the question of whether or not the areas in question have ceased to have the status of forest or other inalienable lands of the public domain.

Forests, in the context of both the Public Land Act^[7] and the Constitution^[8] classifying lands of the public domain into "agricultural, forest or timber, mineral lands and national parks," do not necessarily refer to a large tract of wooded land or an expanse covered by dense growth of trees and underbrush. As we stated in Heirs of Amunategui ^[9]-

A forested area classified as forest land of the public domain does not lose such classification simply because loggers or settlers have stripped it of its forest cover. Parcels of land classified as forest land may actually be covered with grass or planted to crops by kaingin cultivators or other farmers. "Forest lands" do not have to be on mountains or in out of the way places. xxx. The classification is merely descriptive of its legal nature or status and does not have to be descriptive of what the land actually looks like. xxx

Under Section 2, Article XII of the Constitution,^[10] which embodies the Regalian doctrine, all lands of the public domain belong to the State - the source of any asserted right to ownership of land.^[11] All lands not appearing to be clearly of private dominion presumptively belong to the State.^[12] Accordingly, public lands not shown to have been reclassified or released as alienable agricultural land or alienated to a private person by the State remain part of the inalienable public domain.^[13] Under Section 6 of the Public Land Act, the prerogative of classifying or reclassifying lands of the public domain, i.e., from forest or mineral to agricultural and vice versa, belongs to the Executive Branch of the government and not the court.^[14] Needless to stress, the onus to overturn, by incontrovertible evidence, the presumption that the land subject of an application for registration is alienable or disposable rests with the applicant.^[15]

In the present case, the CA assumed that the lands in question are already alienable and disposable. Wrote the appellate court:

The theory of [petitioner] that the properties in question are lands of the public domain cannot be sustained as it is directly against the above doctrine. Said doctrine is a reaffirmation of the principle established in the earlier cases . . . that open, exclusive and undisputed possession of alienable public land for period prescribed by law creates the legal fiction whereby the land, upon completion of the requisite period, ipso jure and without the need of judicial or other sanction, ceases to be public land and becomes private property .... (Word in bracket and underscoring added.)

The principal reason for the appellate court's disposition, finding a registerable title for respondent, is her and her predecessor-in-interest's open, continuous and exclusive occupation of the subject property for more than 30 years. Prescinding from its above assumption and finding, the appellate court went on to conclude, citing Director of Lands vs. Intermediate Appellate Court (IAC)^[16] and Herico vs. DAR,^[17] among other cases, that, upon the completion of the requisite period of possession, the lands in question cease to be public land and become private property.

Director of Lands, Herico and the other cases cited by the CA are not, however, winning cards for the respondent, for the simple reason that, in said cases, the disposable and alienable nature of the land sought to be registered was established, or, at least, not put in issue. And there lies the difference.

Here, respondent never presented the required certification from the proper government agency or official proclamation reclassifying the land applied for as alienable and disposable. Matters of land classification or reclassification cannot be assumed. It calls for proof.^[18] Aside from tax receipts, respondent submitted in evidence the survey map and technical descriptions of the lands, which, needless to state, provided no information respecting the classification of the property. As the Court has held, however, these documents are not sufficient to overcome the presumption that the land sought to be registered forms part of the public domain.^[19]

It cannot be overemphasized that unwarranted appropriation of public lands has been a notorious practice resorted to in land registration cases.^[20] For this reason, the Court has made it a point to stress, when appropriate, that declassification of forest and mineral lands, as the case may be, and their conversion into alienable and disposable lands need an express and positive act from the government.^[21]

The foregoing considered, the issue of whether or not respondent and her predecessor-in-interest have been in open, exclusive and continuous possession of the parcels of land in question is now of little moment. For, unclassified land, as here, cannot be acquired by adverse occupation or possession; occupation thereof in the concept of owner, however long, cannot ripen into private ownership and be registered as title.^[22]

WHEREFORE, the instant petition is GRANTED and the assailed decision dated May 29, 1998 of the Court of Appeals in CA-G.R. CV No. 37001 is REVERSED and SET ASIDE. Accordingly, respondent's application for original registration of title in Land Registration Case No. N-25-1 of the Regional Trial Court at Iba, Zambales, Branch 69, is DENIED.

No costs.