‘Oh, Hi There.’ Forest Cam Captures the Secret Lives of Animals.

“We can’t rely on Mother Nature to create young forests like she has for every century before this one,” said Amanda Cheeseman, a postdoctoral associate at SUNY-ESF, where she oversees Canid Camera.

That’s because the department is unlikely to allow the natural methods like fires and flooding, especially in such a populous region as the Hudson Valley. So to create forest diversity, most biologists maintain that clear-cutting acreage is necessary. Yet despite the endorsement of groups like the Audubon Society to do just this, Mr. Burger said that local residents were attending public meetings and pushing back. Some, worried about climate change, don’t want to see the clearances happen since trees are particularly good at storing carbon.

“Their hearts are in the right place,” Mr. Burger said. “But that’s not sustainable forestry.”

Studies find that mixed-aged forests make the environment more resilient against pest outbreaks, weather events, even climate change. That’s in addition to sustaining species that do best in young forest areas.

And that’s where the camera traps come in. Motion-sensing rigs the size of lunchboxes are attached to trees about a foot and a half off the ground. The traps take a snap anytime something moves, like a family of bears clambering through the frame. But a strong breeze may be enough to trigger it.

Once the photos are uploaded, volunteers can click through as many as they care to, choose a label from a premade list of a few dozen options. There is even a field guide with details on how to tell similar species apart, like gray and red squirrels. Individual pictures are screened 15 times before being marked done. For images with conflicting information — three volunteers see a turkey, say, and the rest see a ruffed grouse — Dr. Cheeseman and her interns weigh in.

“There is a learning curve,” said William McShea, an ecologist at the Smithsonian Conservation Biology Institute, where he helps run eMammal, another camera trap project that relies on volunteers. “People get better at it as they go along.”

Those volunteers do get something in return: a sense of being part of a team. They want to see the best images, interact with researchers on tough photos, and learn something. Some projects even include volunteer names on research papers.