Protected Forests (保護林, Hogo-rin) are areas of national forest in Japan so designated in an effort to conserve biodiversity. Japan's Protected Forest system includes three categories of protected forests: Forest Biosphere Reserves; Biotic Community Protection Forests; and Rare Population Protection Forests. Some of these national forests are linked by a network of Green Corridors that are also included in the system. Established in 1915, the system was overhauled in 2015 and expanded in 2019.

Forests cover approximately two-thirds of Japan, extending over some 25,000,000 hectares (62,000,000 acres); of this, according to the Forestry Agency (林野庁), c.54% is classed as "natural forest", "planted forest" comprising most of the remainder.^[1] In terms of ownership, 58% of all forest is in private hands, state-owned "national forests" (ja) represent 30%, with the remaining 12% otherwise publicly owned, by prefectural and municipal governments, etc.^[1]

Forest conservation measures have a long history in the country: according to the Yōrō Code of 718, "the benefits of mountain, river, grove, and marsh are for government and people alike", with two clauses prohibiting cultivation in the mountains and encouraging the planting of trees along riverbanks and beside dams to counter erosion, while in Kasugayama Primeval Forest (春日山原始林) in Nara, tree-felling and hunting have been forbidden since 841.^[2][3]

Currently, forests are protected under a number of different systems and laws: as Natural Parks under the Natural Parks Act, Nature Conservation Areas under the Nature Conservation Act, Wildlife Protection Areas under the Wildlife Protection and Hunting Management Act, Natural Habitat Conservation Areas under the Conservation of Endangered Species of Wild Fauna and Flora Act, Special Seed Tree Forests (特別母樹林) under the Forestry Seeds and Seedlings Act (林業種苗法), Historic Sites, Places of Scenic Beauty, and Natural Monuments under the Law for the Protection of Cultural Properties—and as Protected Forests and Green Corridors.^[1][4]

Protected Forests date back to an ordinance of Taishō 4 (1915), with the first such forest established the following year, in Kamikōchi.^[5][6] By 1932, there were 93 Protected Forests covering a combined area of 110,000 hectares (270,000 acres).^[5] Demand for timber increased with post-war reconstruction, and the area protected had significantly decreased by the late 1950s and continued to fall through the 1960s.^[5] In 1972, the Forestry Agency issued a new Protected Forest management plan, and in 1973 the area under protection increased 150%.^[5] By 1988, there were 795 Protected Forests, covering an area of 166,800 hectares (412,000 acres).^[5] In 1991, the National Forest Regulations were completely overhauled, with a renewed focus on function and use rather than classification based on species—the four types identified were National Land Conservation Forest, Natural Maintenance Forest, Space Utilization Forest, and Wood Production Forest—and in 2001 the Forests and Forestry Basic Act (森林・林業基本法) was fully revised in line with international trends towards sustainability; the nation's basic forestry strategy and management plan are developed in accordance with this Act.^[1][5]

In 2015, a century after their institution, the Protected Forest system was revised, with the categories reduced from seven to three: (1) Forest Biosphere Reserve; (2) Biotic Community Protection Forest; and (3) Rare Population Protection Forest.^{[1][7][note 1]} As of 1 April 2018, there were in total 666 Protected Forests, covering an area of 977,000 hectares (2,410,000 acres), approximately 4% of the total forested area of the country, and 13% of that represented by national forest.^[8][9] As of 1 April 2019, a network of 24 Green Corridors, established to connect Protected Forests and facilitate interaction between discrete populations, represented a further 584,000 hectares (1,440,000 acres) of national forest.^[1][10]

As of 1 April 2019, 24 Green Corridors (緑の回廊) have been designated, covering an area of 584,000 hectares (1,440,000 acres).^[10]

• Ministry of Agriculture, Forestry and Fisheries (Japan)
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