Farmers in the tropical region of Xishuangbanna in China's south-west Yunnan province recently staged a protest, accusing local officials of colluding with the rubber industry to destroy the local rainforest.
The BBC's Jill McGivering investigated their allegations, which the government denies.
The environmental activist was extremely nervous when he met us, dashing from place to place to find somewhere private enough to talk.
The income from rubber has brought badly needed development
He had reason to worry. He wanted to speak out in support of a group of farmers in a remote part of the tropical region of Xishuangbanna who have made some controversial claims.
Last month the farmers held a protest, complaining that local officials were turning a blind eye to a law that the rainforest must be protected. The farmers alleged that some local officials were colluding with rubber companies, allowing them to flout the rules and cut down the forest to plant rubber trees. Several farmers were arrested.
The activist told me that the farmers were fighting to preserve their traditional way of life.
"Where the forest is destroyed," he told me, "it causes drought. The farmers have to go a long way to get water. And without water, they can't live."
When I travelled to the area and tried to meet one of the protesters, the authorities intervened. Police officers followed, questioned and searched me and later detained my driver.
That surveillance - which lasted three days - made it hard for me to investigate the farmers' main allegation against local officials.
There is no doubt though that the rainforest is under threat.
Chinese scientists who have studied the rainforest say it has declined dramatically. Several decades ago it covered about 70% of Xishuangbanna. That has fallen to about 43% today.
Its existence is extremely important, they say - and not just to the local farmers.
The rainforest harbours extremely rich biological diversity. A great many animal and plant species depend on it. It also affects the region's climate.
Dong Xue-jing is the head of the Xishuangbanna regional government's Forest and Jungles Department.
He denies the rainforest is still being cleared. He was aware of the recent protest, he said, but insisted the vast majority of those responsible for cutting down the forest were foreigners.
"Some people from Vietnam and Laos have been coming over the border and chopping the forest down for valuable natural oil," he told me.
"It's maybe 90% foreigners who are responsible. But we've already arrested five or six of them."
The attractions of rubber are powerful. Many of the villagers in the region are from China's Dai ethnic minority. It has long been a poor area, desperate for development. The rubber has brought new wealth.
I visited one Dai village where local people have chosen to plant rubber. I walked through a dirt yard, past chickens and dogs, and climbed a ladder to the family's raised wooden stilt-house.
Income from the rubber has bought these people new comforts.
"Local people understand about the environment and ecology," the mother of the house told me.
A small patch of rainforest is being preserved in the local botanical garden
"But rubber is powerful. We know it's bad for the environment but we also know that now we have electricity and life is much easier."
The Xishuangbanna Tropical Botanical Gardens is a place of scientific research and is also safeguarding a slice of the original rainforest.
It is already a major tourist attraction for visitors from other parts of China.
Some analysts are optimistic that as Chinese people become wealthier, environmental protection will assume a higher priority.
In the meantime, the Botanical Gardens are preserving one small piece of Xishuangbanna's original habitat.