More than 3 million people visit China's Huangshan mountains each year. Also known as the Yellow Mountains, the range is revered for its scenery and rolling clouds. Among the area's most visited sites is the Greeting Pine.

The Greeting Pine (Pinus hwangshanensis) has been a symbol of Chinese hospitality since the 1950s, according to Sixth Tone. Because the more than 800-year-old tree is an important environmental commodity, it's only fitting that it should have a dedicated bodyguard.

Since the early 1980s, a single person has been responsible for monitoring the health of the Greeting Pine, and this protector works around the clock, rain or shine.

Tree watcher

The tree's current guardian, Hu Xiaochun, is a former soldier who was selected to guard the pine in 2011. He spent a year learning from his predecessor before he was allowed to watch the tree alone.

"I was a soldier for six years. If I receive a mission, I have to do it well," Hu told Sixth Tone.

Hu spends his day monitoring the tree. Every two hours — or every half hour in inclement weather — he checks the tree's support rods and its drainage and lightning protection systems. He uses a magnifying lens to check for bark or needle damage and to look for ants or worms. Hu records everything in a journal, and there are journals dating back to the first pine guardian. Hu is the 19th guardian.

In addition to tiny critters, Hu has to watch out for overeager humans. The Greeting Pine is a popular selfie spot, and with millions of visitors, there are a lot of potential people getting too close. A security system pings Hu's phone whenever someone crosses a barrier.

"Human sweat damages the bark, and we are trying to ensure that it keeps growing naturally," Hu told NBC News.

That same security system helps Hu monitor the tree at night. Once the moon rises, squirrels and monkeys arrive to forage for food. If he gets an alert, Hu leaves his home — a small hut near the tree — to scare them off.

Hu is supported by a team of about 20 other people. Should any actual threats to the tree arise, Hu immediately reports it, and an arborist is dispatched.

Severe weather is another concern. Hu must constantly monitor weather conditions. When Typhoon Haikui struck in 2012, Hu was unable to return to his home about 19 miles (30 kilometers) from Huangshan to be with his infant daughter who had contracted pneumonia.

"I couldn't do anything when I got the call from home, because it was a super typhoon," Hu explained to Sixth Tone.

Hu gets to see his family once a month, and his daughter now calls him the "monkey" when he does return.

But the Greeting Pine has become family for Hu.

"As a pine guardian, if you see the job as only taking care of a tree, then it's meaningless. If you treat the pine as a family member, then it's very different," Hu told Sixth Tone.

And the Greeting Pine has taught Hu things as well.

"The [Greeting Pine] teaches me to be tough. No matter how bad the weather is, nothing brings it down. This is not just a tree. It symbolizes friendship. It opens its arms to welcome people. China is a country of etiquette. The [Greeting Pine] welcomes the world."

China's most iconic tree has a full-time guardian
The Greeting Pine on Huangshan is a popular sightseeing spot in China, but the tree requires protection day and night.