noun
forest reserve; forest preserve
A designated area of forest protected for conservation, research, or watershed management.
この地域は保護林に指定されている。
This area is designated as a forest reserve.
保安林 is a protection forest designated for disaster prevention or public benefit, often with specific management goals.
Compound of 保護 (ほご, 'protection') and 林 (りん, 'forest').