Activist Sasin Chalermlarp will continue to oppose dam projects in the heart of Thailand's national parks despite being named one of 11 members of the National Parks Committee last week, a government post, he told the Bangkok Post in an exclusive interview on Saturday .
He said he is open to proposed dams if they are in remote park areas but not those that threaten environmental conservation.
"I won't challenge all of the proposed dams, only those earmarked for the centre of rich forests, such as the Mae Wong Dam," he said.
"If I can't protect that park from this dam, I will resign."
The cabinet appointed Mr Sasin, who also serves as president of the Seub Nakhasathien Foundation, to the committee on Tuesday. This surprised many given that he has spearheaded opposition to several government projects, particularly the Mae Wong Dam.
He insisted he would keep fighting this project run by the Royal Irrigation Department in Mae Wong National Park in Nakhon Sawan given its central location inside the park.
He will now serve a two-year term on the committee, which is in charge of considering new national park declarations, such as plans to enlarge or reduce the size of particular parks. It is tasked protecting and preserving national parks and offering consultation to agencies.
In 2013, Mr Sasin began a more than 300-kilometre walk from Mae Wong National Park to Bangkok to show his opposition to the construction project.
He told the public the dam cannot effectively prevent flooding as claimed and that it will destroy one of the country's richest forests, now home to tigers sent over from the Huai Kha Khaeng Wildlife Sanctuary.
The project has since been suspended.
Mr Sasin said he has been working hard to find a better water-management solution in place of the dam, such as introducing sluice gates to control water levels, creating water retention areas and diverting water flows so they don't reach towns.
Yet local residents in Lat Yao district of Nakhon Sawan support the dam project as they bear the brunt of heavy rain and flooding every year. Mr Sasin said he has tried to show them there are better solutions to the problem that won't incur the same sacrifices.
His appointment to the state panel has made him something of a political target, with anti-government groups slamming him on social media for what they claim is his lack of resolve. Some said the post was granted him as a "reward" for his support of the government.
"It is ridiculous to think that way," he said. "This post is not a powerful one. The panel doesn't make policy. I feel annoyed at these groundless criticisms."
A former engineer and lecturer who has spent nearly two decades with the Seub Nakhasathien Foundation, Mr Sasin said society is now showing more interest in preserving the nation's national resources and the government is following suit.
One of the government's top policy agendas is to increase the proportion of forest land from 31% of national land area to 40% within 20 years.
Mr Sasin said that growing awareness of just how important conservation is means forestry officials are now more accountable than ever. They have learned from past mistakes and are ready to work with other stakeholders to protest the nation's forests and parks, he added.
His foundation aims to protect and preserve 12 million rai of the country's largest forest complex, which is home to tigers, elephants, gaurs and bulls. It is at risk of forest encroachment and wildlife poaching.
The body was set up in 1990 to mark the death of forest official and conservationist Seub Nakhasathien, who shot himself that year.