These giant trees stretch more than 300 feet above the ground, with hidden gardens and mysterious predators thriving within their canopy. Obsessive redwood climber Steve Sillett of Humboldt State University investigates their monster crowns, tallying biological material and discovering new record-breaking trees, while escaping falling branches and crashing trees in the process. Explorer-in-Residence Mike Fay charts the redwood range.

The sting: Wartz's frog Greenie is afraid of Stripey the bee, but with a little help from his friends, he learns some ways to stay safe around bees. Out on a limb: It's Winslow's birthday and he decides to go where no marmoset has ever gone before. The big sneeze: Bob receives a bouquet of flowers and soon he can't stop sneezing. The itch: Bob has an itch that he thinks is caused by a poisonous plant, so he decides to investigate. Bones: After hurting...