Recently, I took the students in my introductory biology class on a field trip around the college campus. I taught them how to recognize different trees by their branching patterns, the presence of simple or compound leaves, and the shapes of buds and leaves. Ferns could be identified by whether or not they were “once, twice, or thrice-cut.” This is tedious stuff; it requires a lot of careful looking. Yet, if you ask naturalists how they identify trees so quickly and effortlessly, they often say that they recognize the tree by its overall look. How did they go from “keying” out the plant using specific characteristics to seeing the tree as a whole?
I spent the bulk of this summer in northern California which to me, a New Englander, was a foreign land. I decided to learn the names of the most common trees and did this by consulting a field guide and examining the shapes and arrangements of the needles or leaves, the cones on the conifers, the color of the bark, and so on. I found this hard to do. Yet, after a few weeks, all this study paid off. By mid-summer, while riding along in the car, I could easily spot the redwoods, the red firs, the blue gum eucalyptus, and more. I immediately saw the whole tree – not just its parts – or did I?