Throughout the year, the American sweet-gum tree, commonly referred to as the liquidambar, drops its fruit on Sunnyvale sidewalks and streets. The fruit is a hard, brown, spiky ball, smaller than a pingpong ball. The balls are strong enough to resist breaking when stepped on, and their spherical shape makes them roll when weight is put on them, sometimes causing people to slip and fall.

In addition, the trees have a shallow root system that pushes up sidewalks and driveways, causing further hazards. The roots also damage sewer lines and water pipes.

Sunnyvale resident Warner Gans, 73, has been speaking out about the danger posed by the prickly balls for more than a year, and on Aug. 9, the council addressed the issue and made a decision.

"These seed pods are not a nuisance, they are a hazard," said Gans, who added that he is unable to walk in his neighborhood because of the high number of prickly balls on the sidewalks.

In a 6-1 vote--with Councilwoman Julia Miller dissenting--the council approved a plan to allow residents to remove the trees if they replace them with a tree of comparable size, to preserve what city officials call the "urban forest."

All fees for removal will be paid by individual homeowners, but the council is working on finding ways to make it easier to obtain the necessary permits. They also elected to look into funding tree removal when the city has surplus money.

Of the 36,875 trees in Sunnyvale, 3,829 are liquidambars. They drop fruit mainly in February and March, but fruit continues to drop throughout the year. Unlike many trees, liquidambars do not produce fruit for several years after planting, so they do not immediately cause problems.

The city has been removing liquidambars for years, but at a slow pace. Trees of all kinds are removed each year because they become unhealthy or hazardous. According to Marvin Rose, director of public works, almost 30 liquidambars are taken out each year. Because many were planted in the late 1960s, a lot of the trees are old and ready for removal anyway.

Rose said the trees are popular because they produce vibrant fall colors, something many West Coast trees do not. Many residents who come from the Midwest or East Coast enjoy the trees in front of their houses.

But Robert Harms, vice president of the Panama Park Neighborhood Association, said the liquidambar in his front yard has damaged the sidewalk, forcing him to have it repaired, and it has broken sewer lines, causing his toilets to back up.

"If someone likes the colors that much, they can take a trip to the northeast sometime," Harms said at the meeting.