Can I control or limit the number of lines appearing in a field where I have turned on ""log edits to this field""?

Limit lines "appearing" in the field or "entered" in the field? If the question is just on the appearance (in other words, display), I think you have control on it by putting a number underneath the "display" option (number of lines, max characters, and width of input box). I don't know the answer if you want a limit on how many lines a user can enter in the box. Hope it helps.