The CHP on Monday morning closed the Highway 101 north-Third Street offramp into downtown Santa Rosa for the cleanup and removal of a wrecked big rig and a diesel spill.

Officers closed the offramp at about 10 a.m. It was expected to remain closed for about 12 hours, said CHP Officer Kerri Post.

"It's a hefty cleanup," she said.

The rig's driver lost control as he headed north on Highway 101 at about 5:55 a.m.

It was raining heavily and he said at the scene that he'd begun hydroplaning and the tractor-trailer rig began to jacknife.

The 48-foot empty trailer and engine rig ran off of the highway and down the steep embankment. It stopped on its side at the edge of the offramp traffic lanes.

Injuries to the driver apparently were minor. There were no other vehicles involved, said the CHP.

The wreck caused about 40 gallons of diesel fuel to spill into the embankment.

Coast redwoods

The world’s tallest living things, redwoods reach up to 380 feet, higher than a 30-floor skyscraper, and also are among the oldest with a lifespan that can exceed 2,500 years. Redwood fossils date back more than 200 million years to the Jurassic period, when giant reptiles roamed the earth.

The tallest tree at Armstrong Redwoods State Natural Preserve in Guerneville is 310 feet tall; the oldest more than 14 centuries old.

Prior to the Gold Rush, redwoods grew on 2 million acres or more on the West Coast; today only 5 percent of old-growth redwood forest remains, covering just 120,000 acres in a 450-mile coastal strip from southern Oregon to central California, with about 75 percent of it protected in parks and reserves. Redwood forests of mostly young trees cover 1.6 million acres, about the size of Sonoma and Napa counties combined, and less than one-third of it protected.

For more information on the Redwood Genome Project and the location of redwood parks, click here.