The Forestry Act Article 22

Whereas forests held by the state, or a public or private entity which meet any of the following requirements shall be classified as protection forest by the central government agency:1. Essential for preventing damage from floods, wind, tides, salt, and smoke;2. Essential for the conservation of a water source or protection of a reservoir;3. Essential for preventing damage from sand, soil erosion and blowing sand, falling rock, ice, or avalanches;4. Essential to national defense;5. Essential to public health;6. Essential for navigation;7. Essential for the fishing industry;8. Essential to the preservation of landmarks, historic relics, and scenery;9. Essential to nature conservation.
中文原文 森林法第22條
國有林、公有林及私有林有左列情形之一者,應由中央主管機關編為保安林:
一、為預防水害、風害、潮害、鹽害、煙害所必要者。
二、為涵養水源、保護水庫所必要者。
三、為防止砂、土崩壞及飛沙、墜石、泮冰、頹雪等害所必要者。
四、為國防上所必要者。
五、為公共衛生所必要者。
六、為航行目標所必要者。
七、為漁業經營所必要者。
八、為保存名勝、古蹟、風景所必要者。
九、為自然保育所必要者。

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