Election Section

If That Tree Looks Dead, It May Be a Buckeye By RON SULLIVAN Special to the Planet

Tuesday August 16, 2005

Don’t panic, folks. Those trees aren’t dying. 

Our town has a number of public California buckeye trees, some planted in medians (Sacramento Street south of University Avenue, for example) and some in privately owned visible spots: there’s a cute little buckeye on the streetside corner of Andronico’s University Avenue store’s parking lot. Right now, many of them are dropping leaves, or looking brown and sickly. Relax; it’s normal. 

When I took my first tree course ever up at Merritt, Judy Thomas told us that as practicing landscapers we were guaranteed to get this question more than once in our careers: “What’s wrong with my tree?? It’s dying! It’s shriveling up and dropping leaves and it’s only August!” To answer, first we were to find out the tree’s species, and it would probably be a native buckeye. If it was, we could reassure our panicky clients and look like heroes.  

Coastal California is a strange place to be a plant. When the days are longest, there’s no water; when it’s raining, there’s little sunshine for months on end, no matter the weather, because days are short. Plants have to cope either by doing their growing on a diet of scant sunlight or by figuring out how to grow new tissue with little or no available water. Trees in particular make a lot of themselves, of slowly, and make dense wood too, not flimsy stems.  

Back east, say, they have an easier decision. When the ground freezes in winter, that’s effectively a drought, as plants need liquid water to absorb onto their rootlets. Despite summer rainstorms, daylight gets lavished on them in the long days of summer. So they can start their drinking and growing when the ground thaws out—and it doesn’t take much thawing to kick them off, as witness New England’s sugar maples, whose sap flows when the ground is still under snow.  

In winter, northeastern trees have to conserve moisture. Evergreen conifers have small, hard needles or even scales, often with a waxy coat that keeps water in. Deciduous trees have a different solution: After pulling their chlorophyll back into their woody bits and exposing other pigments for a fall show, they just jettison their tender, vulnerable leaf tissue before the winter blasts can desiccate them, or freezing temperatures explode the cell walls—water expands when it freezes. (In a rare freeze here, I’ve seen tender succulents dissolve into sad green mush or even explode, sending shattered bits of nopales several feet into the garden. Yikes.) 

We have several native soft-leafed deciduous trees here, like bigleaf maple and red-twig dogwood. We have broadleaf evergreens like California bay laurel, and of course lots of conifers like redwood. But our buckeye is our only tree species that has reaches this particular compromise, and it makes me wonder about its evolutionary history. It’s bare in winter, and quite handsome that way, with its pale bark and sturdily graceful structure. It leafs out in spring, and flowers with subtly scented upright candles of little white blooms. Those blossoms, by the way, are toxic to honeybees, but apparently not to the various pollinators native here.  

Some of the flowers—not many—mature into hard, red-brown nuts like chestnuts but lumpier, and not edible roasted the way chestnuts are. They do have a grocery value, though—the First Peoples who lived in range used them to stun fish. No, not by conking them on the head like your little brother; by putting some of the pulp into a pond or a creek backwater. Compounds in the nut stunned the fish, who would float helplessly to the top where shoppers could pick the ones they wanted. Most of the rest would recover and swim off, presumably with a piscine hangover, and the pulp would dilute and wash away harmlessly. (A lot of things are harmless when only a few people do them.) 

Then, toward the end of summer, just before the hottest, driest days of September, when the soil is parched and things are beginning to look tired, many buckeyes let their leaves shrivel and drop. The ones that don’t usually live beside year-round creeks, or suckle at some permanent underground water source. The ones that do aren’t hurting, just doing what comes naturally.