We’re getting some domestic fall color lately from a couple of tree species on the streets of Berkeley. One of the brightest is a relative newcomer here, Chinese pistache, Pistacia chinensis.
You can tell it’s a recent arrival because none of the street specimens here is mature. As with a lot of street trees, of course, there’s a chance they never will get old enough to show us their full potential; a street tree’s life is typically nasty, brutish, and short and so, alas, are entirely too many street tr ees. That’s a particular pity with this species because it’s sometimes called “the ugly duckling”: It’s gangly and awkward in its youth, all elbows and weird angles and often quite asymmetrical. It reaches its best form only after it reaches its modest full size, when it turns into a graceful vase-shaped or round-topped tree.
Even in its kinky youth, though, it shows us why people plant it in cities when autumn gives it a nudge toward color. In mild climates like ours, without a color-defining cold snap in October, Chinese pistache still glows with an unpredictable variety of deep crimsons, blazing scarlets, and clarion yellows from amber to canary—sometimes on the same tree. Since there’s a lot of unpredictable color variation among individuals as well as differences in how early each one decides to blaze up, we get a long, multi-note salute from a modest row of trees.
There are plantings a couple of blocks long scattered around the Berkeley flatlands, for example on Gilman Street northwest of Hopkins (next to a set of jacarandas—someone up there likes color) and on Sacramento near University, in the median strip. They’re certainly easy to find right now, when few trees other than sweetgum rival their gaudiness. From a distance, you can sort them out by their skinny, often flat-topped form; up close, by their finely compound, feathery leaves.
Some of them bear fruit, too, though it doesn’t look like much. Only some, because this is a dioecious tree, with female and male organs on separate plants. The fruits aren’t big and I don’t see that they make a huge “litter” problem on sidewalks, so I hope we don’t get too much pressure to breed male-only clones as we have with some city tree species like mulberry. Some of us have all the airborne tree pollen we need, thanks. The rest of you, don’t be too smug; people get surprised by new allergies well into old age.
Chinese pistache is a recent darling in urban landscapes for several reasons. It’s drought-tolerant, certainly a good thing here. It’s heat-tolerant, which is useful even in a relatively cool climate because streets and sidewalks and concrete structures reflect and radiate lots of heat. Cities are typically a few degrees hotter than their rural surroundings, and streets are hotter than the cities’ averages. The “asphalt jungle” is more a desert in many ways.
I’ve seen conflicting opinions about whether the species needs good drainage; I suppose Berkeley, with our clay soils, is a test lab for that. It’s supposed to tolerate smog well. It grows fairly fast, but is usually described as only a moderate-sized tree, to maybe 30 feet. (I’ve seen it called a 60-foot tree too, which might depend on where it’s growing.) I read that it’s “naturalized” in Texas and the Southeast, which means it’s gone feral there, so we do have to think about whether it might become invasive if we plant it near wildland margins here.
Yes, it’s related to the pistachio tree, Pistacia vera, that gives us those nice thin-hulled nuts. Pistachio growers sometimes use it for root stock, grafting the nut-bearing species onto it. P. chinensis’ native range is farther east than its cousin, in east Asia and by some accounts the Philippines. Both are related to the various Rhus species, the sumacs, and all are in the family Anacardiaceae along with cashews and mangoes—and poison oak.
Chinese pistache’s little clustered nuts, which start out green or red and turn red or dark blue about now, are supposed to be good wildlife chow; I’d be interested in hearing if anyone has seen birds or squirrels eating them.