Time for a confession: I don’t actually hug trees. I’m not a big hugger to start with, and trees are scratchy and unyielding. Many have ants trailing up the grooves, baby snails hatching in knots, sap dripping down in slow motion. I may not be a literal tree hugger, but I am a tree lover and an enthusiastic tree watcher.
My tree book collection has exploded in the past year with natural histories, field guides, and photography books. In the space of a year, I have started to look — really look — at trees for the first time. I was originally going to write this post in the fall, when trees still had leaves. But winter is actually a very good time to start looking at trees. Leaves can be so distracting. Without them, you can see the bones underneath and appreciate the architecture.
Precise tree identification is probably best left to the experts, but it’s actually not very hard to get started with the basics. I’d like to share a little of what I know in hopes that the boring old tree outside your window will suddenly become a lot more interesting. My earliest tree lessons came from my mother, who gave me the names to eucalyptus, liquidambar, and mulberry trees early in my childhood. I’m grateful. (Incidentally, this post is only about broad leafed trees. I’m just not that into conifers yet, other than the wonderful coastal redwoods I grew up with. Sorry.)
Looking at Branches: Opposite vs. Alternate
If you can categorize a tree as having opposite branches, you can rule out a whole lot of other possibilities. Only a few tree families have opposite branches, and there’s a handy little mnemonic to help you remember which: Damp Horse (dogwood, ash, maple, paulownia, and horse chestnut). Winter is a good time to check out whether your neighborhood trees have opposite or alternate branches. Be careful, though. While black ashes form clear, dark crosses across the sky, you’ll have to look closer with most other trees. Also, alternate trees will have the odd opposite pair, and vice versa. If you see many pairs of opposite branches, however, you’re probably on to something.
Looking at Fruit/Seeds
Botanists have lots of different names for different types of fruit (drupes, pomes, arils…). I don’t know all of them yet, and you really don’t need to in order to pick out several of the major tree families.
Acorns = Oak (Quercus)
Only oaks bear acorns, so if you see green acorns on a tree or brown acorns beneath one, you’re looking at an oak. Oaks are a crazily diverse family of trees. This photo shows an oak with smooth, deeply lobed leaves, but there are also oaks with sharp lobes (black oak), small spiny leaves (coast live oak), and even smooth, elongated oval leaves (holly oak). Most oaks lose their leaves in the fall, but live oaks stay green year round.
As a very rough generalization, most mature oaks are stout trees with irregular (non-symmetrical) crowns and gnarled branches and trunks.
Paired Samaras = Maple (Acer)
I probably don’t have to tell you what a maple leaf looks like, but not every tree that has maple-like leaves is actually a maple (see plane trees, next), and if that wasn’t enough, there are also maples with leaves that look like ash leaves (box elder). However, all true maples have paired sets of winged seeds, which are called samaras. They spin like helicopters when you drop them, and I’ve always thought they were an instance of awesome design by nature.
Maples include sugar, silver, and Japanese varieties. Many maples turn beautiful colors in the fall, especially on the east coast. Branches are opposite, and as far as I know, all maples are deciduous.
Soft Seed Balls = Plane Trees / Sycamores (Platanus)
If you see a bare winter tree with camouflage like bark (big gray, white, tan, and/or orange splotches) and 1″ seed balls hanging down, especially near the top of the tree, you’re looking at some sort of plane tree (sycamores in American English). The seedballs are a little spongy and surprisingly light for their size. If you pull one open, you’ll find that it’s filled with white fluff, and the brown outside is actually formed of lots of tiny seeds packed together. They’re kind of like inside-out dandelion puffs.
Plane trees have big maple-like leaves, but good luck trying to tap one for syrup. At least in my area, they are one of the most common street trees.
Wicked Spiky Seed Balls = Sweetgum / Liquidambar (Styrax)
There are probably other trees that produce round, brown seed balls. But the sweetgum is so common and distinctive that I thought I’d point it out to you. The sweetgum has star-shaped, vaguely maple-like leaves that turn brilliant colors even in mild California autumns, and after they’re all gone, spiky seedballs hang down from the bare branches like ornaments. Unlike the plane tree’s seed balls, these are spiked all over and very hard. The seeds are dispersed through holes in the ball, leaving the spiky structure intact. These things decompose very slowly — amid the brown ones of this year, you can often see grayer, smaller seed balls of previous years.
Whew! I could go on for a while, but I don’t want to be a bore. I noticed today that some of our street trees (Bradford pears) are already putting out new buds. California trees live in a state of perpetual confusion about when they’re supposed to do what. In the spring proper, I’ll bombard you with information about flowers and leaves.
Have you ever taken a close look at your hardworking and underappreciated street trees? What kind of trees are around you?