This may seem like a silly question (it definitely feels like it has one of those answers that I already know, but just can't dig up). And maybe this isn't the right place for it, but I am asking for the sake of a novel I'm writing, so this is the first site that came to mind. I figured I'd at least be forgiven for it, here, since it's a community of writers.
Here's my question (and an explanation of the problem): I am setting a scene, in which two rows of trees flank a grassy path. Both rows consist of two different types of trees, and here's where my problem with describing that comes in. For the sake of explaining this as clearly as possible, the first type of tree is A and the second type is B. One row is set up like this (ABABAB), so one type of tree is next to the other all the way down the row. How can I describe this without making it obvious that... I have no idea how to describe this (making the description much more difficult and confusing than it needs to be)? I think there's a word that defines this exactly, but I can't catch it.