BANGKOK--A Thai activist charged with trespassing after refusing to abandon farmland in a national park said on Friday that she will appeal her sentence, which campaigners said set a harsh precedent for land rights cases involving forest dwellers.

Earlier this month, a court in Chaiyaphum province in the northeast, sentenced Nittaya Muangklang to 12 months in jail and fines of 140,000 baht ($4,218 or 466,851 yen) for trespassing in the Sai Thong National Park.

It is the most severe sentence yet for such an offense, according to rights groups tracking land cases.

"I will appeal, because I have not got justice," Nittaya said in an interview.

Nittaya's case is the latest involving villagers and indigenous communities in Thailand being evicted from land they consider theirs by birthright, as the rush to develop--or protect green space--leads to disputes over ownership.

Campaigners say evictions have risen since the military government passed a forest reclamation order 2014, which authorities say is essential for conservation.

Nittaya and 13 others from her community were charged with trespassing after they disregarded orders to leave their homes and farms.

"My community and I are not trespassers," she said.

"We lived here long before the policy was passed. If we are to leave this land, where will we go? How can we feed our children and our parents?"

Indigenous and local communities own more than half the world's land under customary rights. Yet they only have secure legal rights to 10 percent, according to Washington D.C.-based advocacy group Rights and Resources Initiative.

The rapid growth of protected areas from Peru to Indonesia has exacerbated their vulnerability: more than 250,000 people in 15 countries were evicted from such areas from 1990 to 2014, according to RRI.

In Thailand, campaigners have long called for amending the 1961 National Park Act to prevent such actions.

Earlier this year, the country's top court ruled that a group of nearly 400 Karen people evicted from the Kaeng Krachan National Park had no legal right over the land.

Nittaya's sentence sets a precedent for more harsh punishments, said Sutharee Wannasiri at advocacy group Fortify Rights in Bangkok.

"It is a worrying example that can be applied to other forest trespass cases," she told the Thomson Reuters Foundation.

"Thai authorities should halt all criminal prosecutions against community members, and review the policy on land and forest management," she said.

A Forest Community Registration Program formally recognizes people living in forests, and benefits more than 11,000 villages nationwide.

But it only covers reserve forests, and not national parks, said Thanyaporn Chankrajang, an assistant professor of economics at Chulalongkorn University.

"The issue is whether, and how to extend the Forest Act to other types of forests, and how to reallocate land rights in areas with overlapping rights," she said.