Landscape Botany of the Sakon Nakhon Basin: A Journey through a Sandstone Landscape of Unexpected Richness

Jul 15, 2026

H
Back to Study Trips

Landscape Botany of the Sakon Nakhon Basin: A Journey through a Sandstone Landscape of Unexpected Richness

Sakon Nakhon and Nakhon Phanom provinces lie within the ‘Sakon Nakhon Basin’, a large sedimentary basin in the upper part of the Korat Plateau. It is separated from the Korat Basin by the Phu Phan mountain range. Notable features include Mesozoic sedimentary rock layers and significant geological structures in both provinces. Phu Phan Mountain Range: A high mountain range running north-west to south-east, serving as a natural barrier that divides the Korat Plateau into two parts: The Korat Basin (south) and the Sakon Nakhon Basin (north). Sakon Nakhon Basin: Most of the area in Sakon Nakhon and Nakhon Phanom lies within this basin. It is characterised as a highland basin with a slope that descends towards the Mekong River.

The Sakon Nakhon Basin is an excellent aquifer that Thais misunderstood for years to have poor water-carrying capacity. In fact, sand and sandstone make excellent aquifers because of their high porosity (space to store water) and high permeability (connected pathways for water to flow). Together, these traits allow the rock or sediment to absorb, store, and transmit large volumes of groundwater. Moreover, it provides natural filtration. Because sand is composed of granular material, it naturally filters out impurities and bacteria as water percolates through it, resulting in clean, usable groundwater. This has made the Sakon Nakhon basin highly biodiverse and culturally rich, as it has been suitable for settlement since the dawn of human civilisation.

Participants will observe the protected forests within Phu Phan National Park and its stone plateaus (Phlan Hin) during the late rainy season. This experience serves as an ecological reference for identifying natural forest patches outside the protected areas. It fosters a deeper understanding of how local inhabitants practise agriculture while conserving natural forest remnants on their private land.

Additionally, participants will exchange ideas with local villagers who, inspired by the natural vegetation, create traditional embroidered and naturally dyed cotton fabrics with ‘Bhukram,’ a renowned local artisan textile group. The journey also offers a glimpse into the community’s traditional way of life and the cultural heritage shaped by their historic settlements, as evidenced by archaeological and historical sites scattered across the Sakon Nakhon Basin.

The itinerary includes a boat excursion on Nong Han Lake, a major wetland that originated from a massive sinkhole caused by the dissolution of underground rock salt layers. This rock salt bed is a prominent feature of the geological Sakon Nakhon Formation, which dissolved over time to create a colossal cavern that eventually collapsed into a low-lying basin that holds water. Following this, participants will explore vegetation patches representing the original forest on the ancient sandbars of the plateau. This exploration highlights the intricate relationship between vegetation and sandy soil, which sustains groundwater sources that feed the basin’s seasonal wetlands.

Finally, the journey concludes in Nakhon Phanom Province to observe changes in the natural riparian vegetation along the Mekong River, as well as the contemporary development challenges affecting both the fragile ecosystem and the traditional culture of the inhabitants of the Sakon Nakhon Basin.

The Siam Society, under the leadership of Associate Professor Dr Kitichate Sridith, warmly invites members and friends to travel across a landscape composed of sandstone bedrock, Sakon Nakhon and Nakhon Phanom Provinces, from 20 to 22 November 2026. Embark on beautiful natural patches of vegetation outside protected areas that will be depleted very soon; how people settle there; how they use biological resources without destroying vegetation; and the landscape that was misunderstood as dry but is, in fact, a wetland. Learn how the native inhabitants have lived on the rich landscape for centuries, and the misunderstood development that will change it forever.

When

Friday, 20 to Sunday, 22 November 2026

Leader

with Associate Professor Dr Kitichate Sridith

Botanist and Former Lecturer at the Faculty of Science, Prince of Songkhla University

 

Booking

See information below

Or contact Khun Thun

studytrips@thesiamsociety.org

 

The tentative programme will be as follows:

Friday, 20 November: Bangkok – Sakon Nakhon
05:00 Meet at AirAsia check-in counter in Don Mueang International Airport (3rd floor of Terminal 2, counter no. 10, entrance no. 9).
06:50 Depart Bangkok for Sakon Nakhon by AirAsia flight FD3510.
08:05 Arrive at Sakon Nakhon Airport. Then proceed to Phu Phan National Park (อุทยานแห่งชาติภูพาน).
Morning: Enjoy walking among the beautiful wildflowers at Phu Phan Nature Trail; the highlights of the wildflowers, named by Her Majesty Queen Sirikit The Queen Mother, Dusita (Utricularia delphinioides), Manee Thewa (Utricularia minutissima), Sroi Suwannaa (Utricularia bifida), Thip Gaysorn (Utricularia striatula), and Sarat Chan (Utricularia caerulea). These enchanting flowers bloom only for a brief period at the end of the rainy season and the beginning of the cool season.
– Visit Bhukram (ภูคราม), where the local villagers create traditional embroidered and naturally dyed cotton fabrics inspired by the natural vegetation, and a renowned local artisan textile group. The patterns on each shirt are inspired by the weavers’ impressions of the scenes, reflecting the images and memories of their daily lives.
Noon: Lunch at Bhukram.
Afternoon: Proceed to Mueang Sakhon Nakhon.
– Explore Nong Han Lake (ทะเลสาบหนองหาร) by boat, the intricate relationship between vegetation and sandy soil, which sustains groundwater sources that feed the basin’s seasonal wetlands.
– Return to the pier and proceed to Tha Rae Village (หมู่บ้านท่าแร่), the largest Catholic community in Thailand, which was founded in 1884 by the French missionary Father Xavier Guego (Xavier Gecco). At that time, a group of Catholic converts, including Vietnamese Christians and local Isan families, left Sakon Nakhon and crossed Nong Han Lake to establish a new settlement on its northern shore. Their new village became a safe place where they could freely practice their faith. Visit St. Michael Cathedral, Francisco Heritage House, Sorin Mansion, and Udomdetwat Mansion.
– Depart Tha Rae Village for the hotel.
Evening: Dinner at a local restaurant.
  Overnight at Phu Sakon Ville, Sakon Nakhon.
   
Saturday, 21 November: Sakon Nakhon – Nakhon Phanom
– Breakfast at the hotel
Morning: Check out of the hotel and proceed to visit KramSakon (ครามสกล), a local shop showcasing Sakon Nakhon’s renowned handwoven indigo-dyed textiles. Using natural indigo from the region and traditional dyeing techniques passed down through generations, local artisans create beautifully crafted clothing, scarves, bags, hats, shoes, and more. Blending authentic craftsmanship with contemporary designs. The shop also supports the local community by providing indigo dyeing workshops for nearby residents, helping preserve traditional craftsmanship while creating sustainable livelihoods.
– Then proceed to Si Songkhram District, Nakhon Phanom Province.
– En route, explore Paddy Field Forests (ป่านาข้าว). These forests are remnants of the original plant communities that persist within rice fields, commonly found throughout Sakon Nakhon Province. They serve as a genetic reservoir for the indigenous flora of the Sakon Nakhon Basin, interspersed among actively cultivated paddy fields. The predominant plant communities across these vast areas are Deciduous Dipterocarp forests and Mixed Deciduous forests. Their primary tree species include Teng (Shorea obtusa), Rang (Shorea siamensis Miq.), Daeng (Xylia xylocarpa), Hiang(Dipterocarpus obtusifolius), and Pluang (Dipterocarpus tuberculatus Roxb.) These plant communities play a crucial role as “stepping stones” for gene flow within the ecosystem, preserving local genetic diversity. Furthermore, they help maintain appropriate groundwater levels, enabling the soil to release sufficient water to support rice cultivation during the rainy season.
Noon: Lunch at a local restaurant.
Afternoon: Visit Khok Wang Yang Community Forest (ป่าชุมชนโคกวังยาง). The community forest we will visit lies on an ancient dune structure overlying the Sakon Nakhon Formation, a geological layer of rock-salt aquifers. The area is a seasonal wetland interspersed with heath forest. During the rainy season, waterlogging renders the soil acidic and saline, lowering nitrogen levels. Consequently, the vegetation resembles plant communities typically found on general dunes, whether on mountain peaks such as Phu Kradueng or along coastal shorelines. During the rainy season, carnivorous plants such as Sundews (Drosera spp.) and Bladderworts (Utricularia spp.) can be found. Additionally, Ant plants (myrmecophytes) such as Dischidia major are present. In the elevated dune areas that remain untouched by floods, the heath forest thrives, with Hiang (Dipterocarpus obtusifolius) and Samet chun (Syzygium gratum) as the dominant species.
– Proceed to Mueang Nakhon Phanom
Evening: Dinner at a local restaurant
– Overnight at Hotel VELA Dhi, Nakhon Phanom.
   
Sunday, 22 November: Nakhon Phanom – Bangkok
– Breakfast and leisurely at the hotel.
– Check out of the hotel before noon and proceed to the restaurant.
Noon: Lunch at a local restaurant.
Afternoon: Proceed to visit Wat Phrathat Phanom Woramahawihan (วัดพระธาตุพนมวรมหาวิหาร). According to local legend, Phra That Phanom (stupa) was first constructed around 535 BCE during the Si Khotrabun Kingdom. The original stupa was built from unfired clay in the shape of a square kiln, then fired to harden it. Measuring approximately 4 metres wide on each side and 4 metres high, it contained a hollow chamber with entrances on all four sides. Once completed, the Breastbone Relic of the Buddha, brought from India by Venerable Mahākassapa, was enshrined within. Over the centuries, the stupa was enlarged and encased several times by successive generations of devotees and rulers. However, many historians believe the present monument was built later, during the 6th – 7th CE in the Dvaravati period.  In 1975, the stupa collapsed after heavy rain and was rebuilt using traditional designs, with the restored chedi completed in 1979. Today, it stands 53 metres tall, crowned by an 8-metre golden spire, giving it a total height of 57 metres. The temple was granted the status of a Royal First-Class Monastery (Woramahawihan) in 1942, one of the highest ranks of royal monasteries in Thailand.
– Visit Wat Hua Wieng Rang Si (วัดหัวเวียงรังษี), an important example of Lan Xang artistic heritage. Its sim (ordination hall) was constructed in 1917; the ordination hall preserves remarkable Hoop Taem (traditional mural paintings) on both its exterior and interior walls. Inside, the murals depict scenes from the life of the Buddha, the Ten Jātaka Tales, and the Ramakien. Executed using traditional powdered pigments, the paintings resemble delicate line drawings, reflecting the exceptional skill and precision of the artists. The colour palette is intentionally limited to indigo, red, green, and black.
– Proceed back to Mueang Nakhon Phanom and visit Mekong Riverine Forests at Wat Phra Phutthabat Wern Pla (ป่าริมแม่น้ำโขง บริเวณวัดพระพุทธบาทเวินปลา). The Mekong riverine forests on the Thai side of the river are endangered habitats rapidly disappearing due to the construction of concrete embankment walls. These riverine forests are vital ecosystems, acting as a natural buffer between the groundwater flowing through the Mekong and the river channel itself. In addition to harbouring high biodiversity, they host specialised plant species capable of withstanding torrential currents (rheophytes). This plant community was once abundant along the Mekong’s flood terraces. Fascinatingly, during the dry season, when the water level recedes, various geophytes can be seen emerging through the river’s rocky rapids. Crucially, the riverine forest serves as a natural water treatment system, particularly for heavy metal contamination. No vegetation absorbs and sequesters heavy metals more effectively than that within these forests. Consequently, a major driver of heavy metal pollution is the destruction of riverine forests and ongoing attempts to alter natural hydrological dynamics.
– Proceed to Nakhon Phanom Airport.
19:55 Depart Nakhon Phanom for Bangkok by AirAsia flight FD3395.
21:05 Arrive at Don Mueang International Airport.
   

The Siam Society reserves the right to change the programme as necessary.

Important notes:

– The Siam Society may utilise photos taken from study trips, lectures, performances, and other activities as part of its public relations and marketing campaign. These photos, which may sometimes contain image(s) of activity participants, can also be featured on The Society’s website and other online social media channels.

– As part of our effort to address the issue of global warming, The Siam Society strongly supports the reduction of plastic waste. We kindly recommend bringing your own water flask during the trip, if possible.

– In the event of cancellation by a participant, or if The Siam Society cancels or postpones a trip due to circumstances deemed to pose a risk to the safety or well-being of participants, all expenses already incurred or committed, including air tickets, accommodation, transportation, deposits, and other related arrangements, will not be refunded. The Siam Society will refund only the unused portion of the trip cost, after deducting all non-refundable expenses and other costs incurred or committed.

Booking:

Contribution of THB 29,500 (THB 31,500 for non-members), single room surcharge of THB 1,950. The contribution will cover transportation, air ticket, meals as mentioned in the programme, gratuities and other costs incurred to make this trip possible. In addition, basic travel insurance is included. A photocopy of the identification page on your passport, together with your preferred seat on the flight, must accompany the booking. Your reservation will be confirmed as soon as the payment has been made. There is a 4% surcharge for credit/debit card payment to cover bank charges. Please pay by cash or cheque payable to “The Siam Society Under Royal Patronage”. Transfer can also be made to The Siam Society travel account at TMBThanachart Bank (ttb), saving account no. 053-2-18000-7, swift code: TMBKTHBK or by scanning the QR code on your right. Once payment has been made, please fax or e-mail the deposit or transfer docket to us.

For further information and bookings, please contact Khun Thun at 02-661-6470-3 ext 205, or studytrips@thesiamsociety.org.The Society’s office is open from 09:00 to 17:00, Tuesday to Saturday.

More upcoming study trips