Nam Phui NPA
Laos’ only National Protected Area (NPA) west of the Mekong, the Nam Phui occupies 1,912 km2 of Sayaboury’s Phiang, Paklai, and Thongmixai Districts along the Thai border in the province’s central region. Steep and rugged ridges – mostly of Mesozoic sandstone and shale, with limestone outcrops at their bases – characterize the NPA’s terrain, with peaks reaching 1,790 meters in the west.
Nam Phouy National Park in Sainyabuli Province
Nam Phui NPA
The Nam Phui NPA is the source of three main rivers – the Nam Phui, Nam Phoun and Nam Lai – which flow east into the Mekong. Mixed deciduous forest dominated by bamboo cover most of the NPA, though the world’s easternmost native teak forests tower over lower elevations, and seasonal evergreens occur along rivers.
Researchers have found evidence of 50 mammal species in the NPA including an estimated 350 wild elephants, possibly the largest contiguous population in Laos, along with gaur, tigers, dholes, serows, and Asiatic black bears. The Nam Phui is the northernmost home of silver langurs, and lar gibbons reside in the NPA as their habitat remains west of the Mekong. Evidence also exists of the Sumatran rhino, and birdwatchers have recorded 70 different species.
Habitat: Steep and rugged ridges mostly of Mesozoic sandstone and shale. Summits along the Thai border reach a maximum of 1,790m. Three rivers drain eastward to the Mekong: Nam Phui, Nam Phoun and Nam Lai. The majority of the NPA is mixed deciduous forest dominated by bamboo as a result of regular burning. Afzelia is dominant in upper canopy. Teak is also present at lower elevations. There are at least 33 mineral licks scattered throughout the NPA.
Location Latitude: 18o 12′ – 18o 58’N
Longitude: 101o 04′ – 101o32’E
Northern boundary follows watershed of Nam Song and abuts the Nam Tan Provincial Protection Forest . Eastern border follows base of an escarpment for c. 60 km from B. Nam Poui in the north to Thai border at B. Houey Khao in the south. Proposed extension would bring eastern boundary to the main road at B. Nakannyang. Western boundary follows border with Thailand for c. 55 km. and in the southwest excludes 17 villages in Thongmixay District.
1912 sq. km
Steep and rugged ridges mostly of Mesozoic sandstones and shales trending strongly NNE. The eastern ridge rises from lowlands at c. 400m to a crest at 700-1000 m. Limestone outcrops occur in places along the base of this ridge. Summits along the Thai border are higher to a maximum of 1790m. Three rivers drain eastwards to the Mekong : Nam Phui, N. Phoun and N. Lai.
200m – 1790 m
Distinctly cool, dry winters, typical of northern provinces . Hot, dry season in March-April carries high risk of forest fires. Annual rainfall estimated 1,500 – 2,000 mm, with pronounced local rain-shadow effects. Elevated western parts of the NBCA and central eastern villages, like B. Nakannyang, appear to have higher rainfall than around B. Nam Phui and B. Navene in the north and along the Mekong valley at Pak Lai.
Main Forest Types
Majority of NBCA is Mixed Deciduous Forest dominated by bamboo as a result of regular burning. Afzelia locally dominant in upper canopy. Teak also present at lower elevations. Seasonal evergreen forests occur along rivers, along the border hills and in parts of the north central region south of B. Navene. Some of these areas fit Vidal’s (1960) description of an Annonaceae-Meliaceae-Sapindaceae forest type.