TAMPA -- Students across Hillsborough County planted tree saplings between 11 o'clock and noon today, hoping to set a record for the most trees planted in an hour on Earth Day.

Every school in the nation's eighth-largest school district had a chance to plant 38 Longleaf pine seedlings in honor of the 38th anniversary of Earth Day. Organizers expected to plant more than 10,450 trees in the symbolic 11th hour of a day focused on being good to the environment.

At Carrollwood Elementary, kindergartners sang their own rendition of Woody Guthrie’s "This Land Is Your Land." Their words were: "Reuse your bottles, recycle plastic, Let’s keep our water clean."

"They’ve never done anything like this before and I’m not sure they would even have been aware of Earth Day," said Tiffany Rix as her son Steven planted one of the school’s 38 pine seedlings. "He was so excited this morning. He wanted to make sure he wore a good shirt."

In the courtyard in front of brick-faced Hillsborough High School, state and local dignitaries posed for photos beside a biodiesel-powered tractor. The handful of saplings they planted were more mature and larger than the version sent to schools countywide.

But in time, no one will know the difference. "Think of all the small trees today that will become large supporters of the environment," Hillsborough Superintendent MaryEllen Elia said.

- Times staff writers Letitia Stein and Jackie Ripley