The AST Dew Tour, the world’s premier season-long action sports tour, began its fourth event of the season on Thursday with the Wendy’s Invitational, which is being held in Portland’s Rose Quarter.

The five-city tour also includes stops in Baltimore, Cleveland, Salt Lake City and Orlando.

The top action-sports athletes in the world are taking part in this year’s Tour, all competing for the Dew Cup that will be awarded in Orlando at season’s end to champions in each of the six disciplines.

The 2007 Dew Cup winners include Nate Adams (freestyle motocross), Jamie Bestwick (BMX vert), Ryan Nyquist (BMX dirt), Daniel Dhers (BMX park), Shaun White (skateboard vert) and Ryan Sheckler (skateboard park).

The following is a list of some athletes to watch for in Portland: Skateboarding: Street skating icon Eric Koston was granted a wildcard to compete on Portland’s newly designed plaza-style skateboard park course. Look for technical tricks and a signature K grind (crooked grind) from this skateboard legend.

Current skateboard vert points leader Bucky Lasek is looking to reclaim the Dew Cup title he won in 2006. Look for smooth, fluid moves from this veteran skater, a Baltimore native.

Skateboard park competitor Ryan Sheckler of San Clemente, Calif., is fresh off a gold medal in X Games 14, and he will have a chance to display his rail skills and street moves in Portland. Known by fans for his successful MTV reality show “Life of Ryan,” Sheckler is a crowd favorite. BMX: Portland is the favorite stop of BMX park competitor Mike Spinner, 20, who won the event last year after landing the first 1080 in American competition.

Watch for him to pull off his newest trick, a quad whip, where he whips the tail of his bike around his body four times before landing.

Two-time defending Dew Cup champion Daniel Dhers is currently undefeated, and straight off a win at X Games 14.

Jamie Bestwick holds the lead in BMX vert points standings, and he has won 13 out of 17 events in the four-year history of the Tour. FMX: Gresham native Beau Bamburg is known as “The Basher” to his friends for his aggressive style of riding. Look for huge trick extension and spot-on consistency when he rides in the Jam session.