The lush green hills that appear in Nan during the rainy season can easily be mistaken for thick forests from a bird's eye view. But a closer look reveals the greenery is in fact maize plantations that last only a few months.
The areas will be stripped bare in the summer after the crops are harvested and their stumps burned, leaving only a dry, brown colour on the once "lush" hills.
State officials call this unattractive picture khao hua lone, or bald mountains, and are attempting to eliminate it through a new reforestation campaign, with Nan picked as a pilot province.
According to social and environmental activists, this will be a difficult task.
The 8.6 million rai of khao hua lone in Nan are part of a total 26 million rai of degraded forest areas which the National Council for Peace and Order now wants to re-claim.
The campaign is raising communities' hopes for the re-growth of trees but also worries farmers, who fear they will be stripped of their farmland, said Prayong Doklamyai, adviser to the People's Movement for a Just Society (P-Move).
In the eyes of many maize growers, the campaign could bring disaster if their land is found to sit on a forest reserve.
Currently more than 800,000 rai of the 1.4 million rai of agricultural areas in Nan are used for planting maize and nearly 90% of maize farms overlap with forest reserves that were established in 1988, said Rat Cootna, deputy chairman of the Association of Maize Growers for Animals.
The problem cannot be easily solved by the existing laws, as both the government and businessmen who buy the maize from farmers share responsibility for stripping the mountains.
It is unfair to point the finger at farmers alone and brand them as "destroyers of Nan forests", said Mr Prayong.
While many farmers encroach on forest areas, a few key agro-business firms keep fuelling the demand for maize, which they buy to use as animal feed.
Nor can the government deny that its past forestry policy sparked deforestation.
In 1969, a need to earn revenue persuaded the government to grant logging concessions to wood trading companies.
Phra Kru Phithak Nanthakun, adviser to the Hak Muang Nan Foundation, said "legal logging" encouraged by this policy took place in many provinces in the North.
The end of the concessions years later did not stop logging, as the villagers who had settled in forest areas needed firewood and land to grow maize under a mono-cropping policy introduced in 1982 to generate income for villagers, the monk said.
Many Nan farmers have since made their living exclusively from maize farming, which promises good money, though some admitted the career has trapped them in what they call a "vicious cycle".
Limited career choices led the villagers to farm. But the money they earn is used to buy seeds from companies and settle debts run up with the state-run Bank for Agriculture and Agricultural Cooperatives (BAAC).
"It's a vicious cycle we can't escape if we don't have alternative careers," Mr Rat said.
To ensure a decent harvest, farmers have to depend on maize seeds sold by agro companies -- even though the seeds, fertiliser and pesticide make up 56% of their costs, Mr Prayong said.
The BAAC's role is also dubious as it continues to grant loans to farmers despite many of them not having land documents or surety, said environmental advocate Banjong Nasae, also chairman of the Rak Thale Thai (marine conservation) Association.
At present, maize growing seems to be the farmers' most reliable source of income because the crop does not require much water and can grow on mountainous terrain, Mr Rat said.
The timing of the new government campaign to reforest maize farms is unfortunate, he added.
Though environmental advocates agree with the move, they want authorities to handle forest encroachment cases carefully to determine whether the farmers occupied land before or after the forest reserves were announced.
The government should pay heed to the farmers' voices and join hands with agro-business companies to find ways to compensate the farmers if they have to leave the land, Mr Prayong said.
Nan farmers may be viewed as forest destroyers, but "I want them to view the problem from our stance, too. Now we have no other choices except maize farming", Mr Rat said.