The Forestry Act Article 7

Should any of the following criteria apply to a public or private forest, the central government agency may appropriate it to national ownership, and shall compensate the owner accordingly:1.It is required for reasons of land conservation or the administration of national forests.2.It includes a river, lake or other water source that provides important resources to the public.Any acts relevant to land expropriation may be applied when appropriating land for national ownership. The procedure for appropriating a public forest may follow the relevant rules of public property management.
中文原文 森林法第7條
公有林及私有林有左列情形之一者,得由中央主管機關收歸國有。
但應予補償金:
一、國土保安上或國有林經營上有收歸國有之必要者。
二、關係不限於所在地之河川、湖泊、水源等公益需要者。
前項收歸國有之程序,準用土地徵收相關法令辦理;公有林得依公有財產管理之有關規定辦理。

English translation for reference only; the Chinese text prevails. Not legal advice.