How to measure a tree

I recently finished reading a book called The Tree Collectors: Tales of Arboreal Obsession, by Amy Stewart. It contains portraits of people obsessed with trees in one way or another. My only complaint is some of these collectors are importing trees from other parts of the world without a concern that they may be introducing an invasive species into their own habitat; one has even planted Russian olive! It's a pleasant read, if you are so inclined.

One section discussed "champion" trees - the really, really, REALLY BIG ones. Points are awarded for girth, height, and crown spread. My trees are definitely not champions, but an annual measurement would give me a more objective idea of how they are growing (besides eyeballing each one and thinking, Yep, it's bigger this year).

Rather than repeat what the books says, here are some lousy photos of the relevent information:

My trees are mostly naked right now, so I'll wait until next summer to measure them. Hopefully, that will become an annual occurance.