Noun function: It acts as the direct object of the verb "likes".
Here's why:
* Gerund: "Climbing" is a verb form ending in "-ing" that functions as a noun.
* Gerund Phrase: The phrase "climbing trees" expands on the gerund "climbing".
* Direct Object: The direct object receives the action of the verb. In this sentence, the daughter "likes" the action of "climbing trees".