HAIKOU, June 5 (Xinhua) -- Liu Daye, 53, spent 11 years cutting down trees in the Jianfeng Ranges, home to China's largest virgin tropical rainforest. But he has now spent even more time preventing humans from harming the woods.

"What I am doing now is making up for what I did in the past," Liu said.

More than 3,000 plant species and over 4,700 animal species inhabit the rainforest in the western part of the island province of Hainan.

For at least 22 days of each month, Liu patrols over 100 km through the woods, searching for traces of poachers or fire hazards, and monitoring the environment.

From 1981 to 1992, Liu worked for a logging company, which had seven forest farms and nearly 6,000 employees in its heyday.

"The country's construction boom at the time required a lot of quality wood," Liu recalled. "But the way to fell trees was destructive."

Lumberjacks preferred the best and biggest trees, leaving the forest in a bad state, he said.

Liu and his fellow workers dropped their axes and saws after rising awareness of environmental protection led to the end of logging in the forest in 1993.

In 1998, a conservation campaign was launched to restore the forest. Two years later, some former lumberjacks, including Liu, were hired as rangers. He earns some 4,000 yuan (623 U.S. dollars) a month as a ranger.

The most dangerous part of the job is dealing with poachers.

In late 2010, two poachers riding through the forest on a motorcycle encountered Liu who was on duty. Liu grabbed a shotgun from the hand of one of the pair and inserted it into a wheel of their motorcycle.

The poachers fled, Liu said. "But at least I took their weapon," he demonstrated the twisted barrel of the gun.

The rangers' work also includes raising the awareness of villagers in wildlife protection and assisting biologists with their research.

Once, Liu and his colleagues saved a boa constrictor that had entered a village and was caught by villagers. The villagers planned to kill it until Liu told them that it was under state protection.

"It is not an easy job, but I'm so glad to see what we have changed," he said.

According to statistics from the forestry bureau in the Jianfeng Ranges, the area of the rainforest has increased by nearly 60,000 mu (4,000 hectares) during the past 20 years.