The boys kicked the dead tree, tempting the 90-foot widow-maker with each stomp, caught in the exuberance of outdoor adventure.

They were deep in the backcountry of Idaho, 3 ½ miles from the nearest forest service road, a bumpy affair miles from the closest town. They were collecting firewood.

For 10 minutes, they kicked and knocked the dead snag, until Addison Ditto delivered the fateful blow, a “Spartan kick” delivered with vim and vigor by the 110-pound high school junior.

The pine had enough. It fell.

Carried by gravity, its base tumbled away from the boys while the top half broke and fell toward the four teenagers.

They scattered. Most ran to the side of the falling behemoth. But Ditto ran directly away from the tree, which came crashing down in an explosion of rotten, waterlogged wood, dirt, moss and branches.

His left leg was caught.

“He was lying there screaming,” said Jack Overholser, a junior at Innovation High School in Spokane, Wash. “Me and my buddy JT [Wilson] had to lift the tree off his leg while he was screaming. That was probably the most traumatizing part.”

Ditto sat up and saw his “lower calf hanging.”

“This is not good,” he recalled thinking.

The next several hours were a blur, but thanks to quick thinking and good training, Ditto was back in Spokane, safe at Sacred Heart Children’s Hospital that night.

The 13 boys were on a three-day camping trip as part of the charter high school’s Evergreen class.

Taught by Ole Haakon Reiersoelmoen, the class takes science (physics, chemistry or biology, for instance) and shows its application in the outdoors. Students go on overnight field trips once a month and have day trips nearly every week. They’ve gone kayaking, estimating how quickly the river is flowing. They’re taking an avalanche training course this winter to learn about the physics and chemistry of snow.

They also study outdoor survival and preparation, all of which left them uniquely prepared to deal quickly and efficiently with the backcountry emergency. After the tree fell, the rest of the class gathered around, including Reiersoelmoen and another instructor.

They splinted Ditto’s leg and built a stretcher from tree branches and a tarp. This was, in fact, something they’d practiced doing just the week before, using Ditto as the victim. “We knew exactly what to do,” Overholser said.

They contacted the school and authorities using their emergency communication device and kept an eye on Ditto, who was in shock.

Once Ditto’s leg was stabilized (using branches and tape) and the stretcher was built, half the group started to carry him the 3 ½ miles out. The other half stayed behind with the second instructor.

The hike out was incredibly painful for Ditto. “During the miles, I was just yelling and screaming,” he said.

Around 7 p.m., they got back to the trailhead. Ditto was taken to the Newport hospital, where his parents met him. He had broken his shin. He had surgery and is recovering well.

As for lessons learned? Be prepared and expect the unexpected, Ditto said. His classmates added the importance of having a first aid kit, hiking with friends and having a way to communicate with the outside world. And added one: “Don’t knock down trees.”