The discovery of at least six cubs in Thap Lan National Park, which connects to the Unesco World Heritage-listed Dong Phayayen-Khao Yai Forest Complex, is giving conservationists hope that Thailand will be able to double its tiger population by 2022.
The precise location of the discovery of the cubs has been kept secret to prevent hunters finding them.
According to a camera installed in the forests by the Department of National Parks Wildlife and Plant Conservation (DNP), between June last year and February this year there were an estimated 160 tigers in the national park.
Their major homes are in the Western Forest Complex's Huai Kha Kaeng-Thung Yai Wildlife Sanctuary, the Phu Khew-Nam Nao Forest Complex, and the Eastern Forest Complex's Dong Phayayen-Khao Yai Forest Complex.
The Huai Kha Kaeng-Thung Yai Wildlife Sanctuary is the biggest tiger habitat with around 70 tigers.
In 2010, Thailand and other governments from 13 countries where wild tigers are known to live launched conservation efforts to double the number of wild tigers by 2022, the Chinese year of the tiger.
Currently, there are less than 3,200 tigers living in the forest, down 97% from 100,000 a century ago, due to poaching, and loss of forest reserve caused by human activities.
Songtham Suksawang, director of the National Parks Division, said female tigers in the wild usually give birth twice a year; the problem now is how to provide enough food and territory for them.
If there is enough food, safe territory and a good patrol team that can prevent wildlife poaching, the tiger population is certain to increase, he added.
"We have found new cubs in the park for the first time in 15 years. This reflects the importance of having an effective patrol system. "If everything is in place, we are likely to meet our target of doubling the tiger population,'' said Mr Songtham, adding successful measures will be replicated at other tiger parks.
According to the department, there are 18 tigers living in the Eastern Forest Complex.
He said there is a possibility the tigers will be moved from Thap Lan National Park to Khao Yai National Park after the construction of a wildlife corridor is complete.
"Camera footage shows tigers walking around the place close to the construction site. We hope the tigers will use it to cross to Khao Yai, which could become a new home for them as their population increases," added Mr Songtham.
The wildlife corridor will soon link both national parks, which were earlier cut off by Highway 304.
The World Heritage Committee suggested the wildlife corridor be constructed to link the two parks and enable wildlife to thrive.
The work is expected to be completed in August next year.
The department is also aiming to promote both Tanithay National Park and Kaeng Krachan Forest Complex in Phetchaburi province with the intention of their being awarded Trans-boundary World Heritage status. However, unsettled border issues have so far hindered these ambitions.
In 2012, two cubs and eight tigers were moved from the Huai Kha Khaeng Wildlife Sanctuary to Mae Wong National Park and Klong Lan National Park.
The cubs were proof that the wildlife sanctuary's tiger population was growing.
In the Western Forest Complex, the department also found an increasing number of cubs, two in 2012, five in 2014 and six in 2016.
To allow the tiger population to thrive, the department is planning to link the western forest in Kanchanaburi province with the Kaeng Krachan Forest complex, after it found one tiger had travelled from Huai Kha Khaeng to Salakpra National Park in Kanchanaburi province in 2014, around 100km from the original site, suggesting the animals need more space.
It is hoped the link will expand the habitat range to the Kaeng Krachan Forest Complex, also on a draft list that will be submitted for World Heritage status.
Meanwhile, Petch Manopawitr, IUCN's conservation scientist, said forest officials have done an outstanding job on tiger conservation in core areas by using a comprehensive ''smart patrol system'', which can help reduce wildlife poaching.
"They must not lower their guard on conservation."
"What they have done already proves these methods work," he said.