After the war, on July 1, 1945, the DAC was reconstituted on account of the changes made by the Philippine Republic. A reorganization act in 1947 brought back the name Department of Agriculture and Natural Resources but transferred the Bureau of Commerce and Weather Bureau to a new Department of Commerce and Industry. The Divisions of Fisheries and Natural History Museum were transformed into bureaus and were placed under the Office of the President.
An enabling act in 1953 added the Bureau of Agricultural Extension to the DANR. On this same year, the Office of Agricultural Information was established.
There were no major changes in the DANR's structure from 1954 to 1974. However, the end of DANR came on May 17, 1974 when Presidential Decree No. 461 was issued providing for the Department\'s reorganization into 2 departments, namely: the Department of Agriculture (DA) and the Department of Natural Resources (DNR).
Under this set-up, the DNR took the following line bureaus and attached agencies: Bureau of Forest Development (BFD), Bureau of Mines (BM), Bureau of Lands (BL), Bureau of Fisheries and Aquatic Resources (BFAR), National Committee for Mineral Exploration and Survey Operations (NACOMESCO), Presidential Committee on Wood Industries Development (PCWID), Fishery Industry Development Council (FIDC), Surigao Mineral Reservations Board (SMRB) and the Presidential Action Committee on Land Problems (PACLAP).
Certain agencies were created later on and attached to the DNR. These were the Forest Research Institute (FORI) established on December 8, 1974 under PD No. 607; the Philippine Fish Marketing Authority (PFMA), on August 11, 1976 under PD No. 977; the Natural Resources Management Center (NRMC), on October 25, 1976 under PD NO. 1041; the National Environmental Protection Council (NEPC), on April 18, 1977 under PD No. 1121; and the Mineral Reservation Development Board (MRDB) taking over the functions and powers of the abolished SMRB on February 1978 under PD NO. 1305.
With the shift to a parliamentary form of government in 1978, the DNR became the Ministry of Natural Resources (MNR). A component arm, the Natural Resources Development Corporation was started under Executive Order No. 786 in 1982.
In 1985, the concern on fish and fisheries was transferred to the Ministry of Agriculture, leaving the MNR with only three (3) bureaus aside from the attached entities.
On January 30, 1987, Executive Order No. 131 was issued creating the Department of Energy, Environment and Natural Resources (DEENR) that took the powers and functions of the MNR and embraced the emerging critical concerns about energy and environment. However, EO 131 was never implemented. Executive Order No. 192 came out on June 10, 1987, reorganizing the DEENR and renaming it as the Department of Environment and Natural Resources (DENR).
The main features of EO 192 were the transfer of the energy matters to the office of the President and the decentralization of the bureaucracy by transforming the former line bureaus to staff bureaus and transforming most of the line functions to the regional and field offices. These features are in fact dramatic changes for they radically altered the concept of the bureaucracy and for the first time moved to institutionalize the decentralization of functions and authority within the Department.
In 1993, Laguna Lake Development Authority (LLDA) was attached to the DENR by virtue of Executive Order No. 149, thereby adding to the mandate of the Department its complete supervision.
In October 1993, by virtue of A.O. No. 90, the Project Management Office (PMO) on Solid Waste Management under the Presidential Task Force on Waste Management was created, with the DENR as the lead-executing agency. The PMO assists the Task Force in the formulation of the necessary standards/guidelines and criteria for effective, efficient and economical waste management.
In 1995, the passage into law of the Philippine Mining Act or R. A. No. 7942 restored the line function of the Mines and Geo-Sciences Bureau.
On October 15, 1996, Executive Order No. 374 was issued creating the Presidential Task Force on Water Resources Development and Management (PTFWRDM), chaired by the Secretary of the DENR. PTFWRDM is tasked to coordinate the projects of various government agencies and departments involved in water to ensure efficient management and development of the country's water resources.
Source : http://denr.gov.ph/about-us/history.html