CALIFORNIA—A rusty brown bark beetle, the length of a grain of rice, lands on a ponderosa pine. Tiny insect legs make a clicking sound as the beetle scales the tree. Twitching its antennae, the miniature assassin readies itself to bore into the pine, often the tree’s death knell.

This scene is from episode 3 of Netflix documentary “Our Living World,” which explores how climate change is upending the natural world as we’ve come to know it. USDA Forest Service scientists Chris Fettig, Danny Cluck and Leif Mortenson served among the film’s scientific consultants, sharing their knowledge and research on bark beetles and, in the case of Cluck and Mortenson, taking the camera crew into the forest for filming.  

“Even though the bark beetle scene only lasts four minutes (from about 33:00 to 37:00), it took days of filming,” Fettig stated.

The scientists were careful to choose an area of Tahoe National Forest where tree mortality was already high. They were essentially signing the trees’ death certificates, so they didn’t want beetles attacking healthy pines.

“We were thoughtful about where we were attracting beetles and also made sure the trees we used were not located near communities,” Cluck said.

Cluck has worked as an entomologist for the Modoc, Lassen, Plumas and Tahoe national forests and the Lake Tahoe Basin Management Unit for over 20 years. Corralling beetles for this documentary was not his first rodeo.

“I took staff from San Francisco’s KQED NPR affiliate out into California forests to film beetle infestations for their ‘science shorts.’  I think those films helped capture the attention of Our Living World’s producers,” Cluck said.

The Filming Process

The executive producer for the United Kingdom-based Wild Space Productions first approached Fettig about assisting with the documentary in 2019, and he eagerly agreed.

“I thought it was a great opportunity to amplify our work on bark beetles to a public audience,” Fettig said.

Fettig has spent years studying bark beetles, which ravage battle-weary trees already contending with wildfire and drought. Compromising the already weakened trees, warming temperatures accelerate the lifecycles of some beetles, which strip forests of their foundation, the mother trees, the oldest and largest in the forest.

Five years after the producers first approached Fettig, the documentary began streaming in April 2024. It features breathtaking footage that transports viewers to far-flung destinations, including Tahoe National Forest. Aerial footage with drones gives viewers a beetle’s eye view of flying. For this scene, the scientists summoned their inner beetles.

“No one truly knows how beetles actually fly, but we gave it our best, educated guess,” Mortenson said.

After capturing beetles boring into pines, the documentary pans to a forest engulfed in towering flames. Although bark beetle outbreaks alter forest fuels by killing large numbers of trees, Fettig cautions that they don’t always cause or worsen wildfires.

“Bark beetles are only one factor influencing wildfires. Dense forests from a history of fire suppression, the location of a fire, weather during the fire, and other factors also affect wildfire severity,” Fettig stated.

Ironically, after filming a wildfire scorched an area of the Tahoe National Forest featured in the documentary.

Reason for Hope

In that spirit of teamwork, the scientists are working together to make forests more resilient in the future. And they’ve made strides.

Fettig and fellow scientists, for instance, have had success in repelling beetles from trees using a pheromone called verbenone and other repellents. Like a flashing ‘no vacancy’ sign, verbenone tells the beetles, “this tree is full and closed for business.”

“The documentary is powerful and has a valuable message. But we also want those who watch it to believe that there’s reason for hope in the fight against climate change,” Fettig stated.