When does an adjective require 的 to describe a noun?
Single character adjectives do not need possessive 的 when it is connected to single character nouns


  利刀， 大樹，好人


Single character adjectives do not need possessive 的 when it is connected to multiple characters nouns


  利斧頭，大樹屋(tree house)，好女兒


Two characters adjectives need possessive 的 when connected to single character nouns


  鋒利的刀, 巨大的樹， 混亂的心，cannot be reduced to 鋒利刀, 巨大樹， 混亂心


Two characters adjectives do not need possessive 的 when connected to two characters nouns


  鋒利武器，重大事件，混亂心情


An adjective phrase contains more than one or more individual descriptions need possessive 的 when connected to nouns


  鋒利(而)昴貴的武器， 强大(而)勇敢的人 cannot be reduced to 鋒利(而)昴貴武器，强大(而)勇敢人


If you can insert 而 between the two descriptions, you need the possessive 的

Note:

When you can bond an adjective and noun into a single common
term, the possessive 的 would not be needed

強大的人 --> 強人

高大的樹 --> 大樹

巨大的石頭 --> 巨石

春天的雨 --> 春雨 


  強人(strongman)，大樹 (tall tree)，巨石 (boulder)，春雨(spring rain) are all common terms,