Okay, the user wants me to translate "oak-tree" into Danish. Let me check the rules again. The first rule says to translate all content into Danish. The second rule states that if the content is already in Danish, leave it unchanged. The third rule is to provide only the translation result without explanations.
So, "oak-tree" is an English term. In Danish, the word for oak is "eg," and "tree" is "træ." However, when referring to a specific type of tree, like an oak tree, in Danish, it's commonly just "eg" because the species is already implied. So "oak-tree" would translate to "eg." I need to make sure there's no compound word or different term used in Danish for "oak-tree." Checking a reliable source or dictionary confirms that "eg" is the correct translation. The user wants only the translation, so I'll just output "eg" without any explanations or additional text.