Spring arrives on Sunday, and in the nation’s capital, that means a certain tree is bursting in radiant cream-colored flowers.
I’m not talking about the cherry blossoms. They may draw the crowds, but for most people in the Washington area — and, for that matter, much of the East Coast and the Midwest — the far more widespread Bradford pear is the true harbinger of spring. The tree bursts with delicate, five-petaled blooms when most everything else is dull and brown.
The Ups and Downs of the Bradford Pear
by Gabriel Popkin
illustration by Jeannie Phan
http://www.nytimes.com/2016/03/19/opinion/the-ups-and-downs-of-the-bradford-pear.html
Spring arrives on Sunday, and in the nation’s capital, that means a certain tree is bursting in radiant cream-colored flowers.
I’m not talking about the cherry blossoms. They may draw the crowds, but for most people in the Washington area — and, for that matter, much of the East Coast and the Midwest — the far more widespread Bradford pear is the true harbinger of spring. The tree bursts with delicate, five-petaled blooms when most everything else is dull and brown.
For this display, we can thank scientists at a Department of Agriculture facility in Glenn Dale, Md. More than a half-century ago, they selected the Bradford cultivar for public release from among trial plantings of the Callery pear, a tree that had been collected from China. When it was released in 1960, people went bonkers. “Few trees possess every desired attribute, but the Bradford ornamental pear comes unusually close to the ideal,” a reporter gushed in this newspaper.
Lady Bird Johnson planted a Bradford pear in 1966 in downtown Washington, to promote its use as a landscape tree. It quickly spread up and down residential streets and boulevards. Prince George’s County, Md., where Glenn Dale is, declared it the official county tree.
Today, the Bradford pear may be the most despised tree in this part of the world. Its wood splits easily, making extra work for utility and public works crews. Its offspring pop up unbidden in forests and parks. Its blossoms are fragrant — but not in a good way. Comparisons to semen and rotting flesh are common.
The Bradford pear has been called a “scourge,” a “weed” and a “monster.” I serve on the volunteer tree commission of the small Maryland town where I live, and almost everyone I know who works with trees — including me — thinks the Bradford pear is just plain ugly. Its branches grow into a ridiculous pyramid shape. Its shellacked trunk and waxy leaves look more like plastic than anything nature would produce. Even the flowers seem to me gaudy and overwrought, the arboreal equivalent of a cheap, oversize gemstone.
“The Bradford pear has gone from a great tree that put many nurserymen’s kids through college to an abomination,” says Richard Olsen, the director of the National Arboretum in Washington.
How could a tree that people once swooned over have become such an unwelcome presence?
For many years, foreign plants were sought after. Arboretums boasted about all the foreign varieties they displayed. Plant collectors greatly expanded the options for homeowners, making attractive foreign specimens like the Japanese maple available to the masses. The boom following World War II also multiplied manyfold the suburban yards and streets available for landscape trees.
But seeds can spread beyond tree boxes and gardens to forests, where they compete with native species. The Bradford pear cannot by itself produce fruit, but by hybridizing with other Callery pear varieties, it has earned a spot on the growing list of invasive plants that, to many eyes, pollute any landscape where they appear.
Tastes have also changed. A manicured yard of foreign plants kept free of insects by chemicals is not necessarily the ideal anymore. Gardeners now choose native plants specifically to attract native insects. Common milkweed is not going to win any beauty contests, but thousands of people plant it anyway because it attracts butterflies. In newsletters and online, gardeners buzz about the insects pollinating and consuming their native plants.
Science is now supporting this trend. The University of Delaware entomologist Douglas Tallamy recently compared the number of caterpillar species on a native white oak in his yard to those on a Bradford pear in his neighbor’s. The tally was 19 to one the first day, and 15 to one the next day. Birds, Dr. Tallamy notes, nourish themselves on these native caterpillars. To follow his logic, planting a Bradford pear would be tantamount to avicide.
Municipal tree departments have turned squarely against the pear because of its tendency to shed branches onto sidewalks and power lines, especially when not pruned properly during its early years. Some cities, including Pittsburgh and Lexington, Ky., have banned new plantings of Bradford pear; others are removing the trees. Prince George’s County finally capitulated in 2009 and named the (native) willow oak its new official tree.
I’m no Bradford pear fan, but I wonder if our need for villains in our environmental narratives has gotten the better of us on this one. Whatever the tree’s faults, it’s a living, respirating, photosynthesizing plant. It still makes shade on a hot day. It still sucks carbon dioxide out of the air. It still stops rainwater from pounding the soil and running off into sewers. The Bradford pear may not nourish 19 species of native caterpillars, but it seems to support one.
In cities and suburbs, the Bradford may not be such a bad neighbor after all. Ecologically, it sure beats a road or a shopping center.
At the same time, we’re losing more and more of our native tree options. American elms almost inevitably get Dutch elm disease if they live long enough, and can be maintained only through constant pruning and replacement, and at great expense. The seemingly unstoppable emerald ash borer is putting a quick end to the ash’s days as a street tree. Possible threats also loom over our oaks and maples, whose loss would be an urban ecological disaster.
All things considered, the pear’s crimes start to seem pretty minor. We certainly shouldn’t plant more Bradford pears. But if we’re going to spend time and money righting past environmental wrongs, there are far more important battles to fight than one against a lousy tree.
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日本でもマメナシが自生していて、天然記念物に指定されていたりする。