Dao Wadueng Cave

Lawa Cave

Sai Yok Noi Waterfall

Sai Yok Lek Waterfall

Sai Yok Yai Waterfall   

      The general topography of the national park consists of mostly folded complex mountains with an average elevation ranging from 300 to 600 meters above sea level. Gradients are steeper on the western side. The highest point in the national park is Khao Ro Rae, which is approximately 1,132 meters high and located on the southeastern boundary line. Next to the foothills is an undulating plain in between valleys and rivers, which was formed by sediments from the rivers, These areas are not very large due to the fact that most of the area are valleys.
        The overall gradient is moderately high, especially in the central-north-south. The western regions and some areas near the Khwae Noi River has lower gradients, where the slopes are between 0 and 8%, wider than other points, though this only appears on the eastern bank of the upper Khwae Noi River, flowing through Wang Krang, Ban Sai Yok, and Sai Yok National Park Headquarters in the east along the Mae Nam Noi Creek, Phueng Creek and the central part of the  Haeng Creek area and  Bong Ti Creek. 
The northern border is adjacent to Huai Khayeng National Reserved Forest and the the south borders Wang Yai Mae Nam Noi National Reserved Forest. The eastern border is adjacent to Erawan National Park and on the west side is Myanmar.

      Sai Yok National Park is abundantedly forested highlands, and there is also a long ridge that separates Thailand from Myanmar. As a result, the climate in the area varies greatly. It is affected by monsoons, which makes the air cool and dry in winter and very wet during rainy season. Refer to the data from the Meteorological Monitoring Station in Mae Klong River, which is closest to Sai Yok National Park, the climatic characteristics can be summarized as follows:

Seasons: There are three distinct seasons, 
• Rainy season runs from mid-May to October with most rain in September.
• Winter starts in November and ends in mid-February; December is the coldest month.
• Summer starts around April to mid-May. During this period, the southern winds cover the area, causing sweltering heat. April is the hottest month of the year and it is very hot in this area.

Temperatures:
        Most of Sai Yok National Park is mountainous which affects the temperatures, but generally it is sweltering in summer and relatively cold in winter. The annual average temperature is about 27.02 degrees Celsius, with average minimum temperature of 15.43 degrees Celsius, and the average maximum temperature of 31.1 degrees Celsius.
The humidity of the area is quite high, especially in rainy season. In winnter, mornings can be cold even though the relative humidity is high. In summer, the weather is arid and sultry. The annual average relative humidity of the whole area was 76.5%. The highest humidity in February was 89.92%, and the lowest humidity in June was 62.30%.

Rainfall:
        Annual rainfall is not particularly high on average because of Tanaosi Mountain range, which run along Thailand's border with Myanmar creating a rain shadow and lower wind strength. Some parts have no rain. The total annual average rainfall is 975.4 millimeters with September being the wettest month with 178.2 millimeters. There is almost no rainfall in January, February, and March.

Natural Vegetation
         Most of Sai Yok National Park is mountainous, ranging in elevation from 100 meters to about 1,125 meters above mean sea level. As such there is a variety of ecosystems at different altitudes.

         From the readings and interpretations of the satellite images and a ground inspection in 1990, the forest area in Sai Yok National Park is divided into seven parts. The size of each component is expressed as a percentage of each site in Figure 10. The Royal Decree stated the park covers an area of 958 square kilometers, and it shows the different ecosystems. The satellite images helped discover, important plant species.

      The primary ecosystem in the Sai Yok National Park area is a mixed deciduous forest. The mixed deciduous forests cover an area of 810 square kilometers, accounting for 84.5% of the Sai Yok National Park. They can be divided into mixed deciduous forest and bamboo forest. The remaining 15.5% can be divided into dry evergreen forest and deciduous dipterocarp forest, although some areas have been encroached onto by locals and are used as agricultural land.
Each of the 3 different ecosystems possesses specific conditions and types of wood, as follows:

Mixed Deciduous Forest
       Mixed deciduous forests cover most area in the National Park (810.03 square kilometers or 84.47%), found between 150 - 600 meters above sea level. This forest type canopy has 4 levels. The height of the top canopy is about 25-30 meters and home to plants such as Homalium Tomentosum, Terminalia Nigrovenulosa Pierre, Iron Wood, and White Myrtle. The second canopy layer, at a height of 20-25 meters is home to plants such as Velvet Tamarind (Dialium cochinchinense Pierre), Fernandoa adenophylla , Bombax anceps Pierre, Schleichera oleosa, Terminalia corticosa. The third canopy is at 15 - 20 meters and includes Pterocarpus macrocarpus Kurz, Croton persimilis Mull. Arg., Canarium Subulatum Guillaumin, Siphonodon celastrineus Griff., Cassia garrettiana, Lophopetalum Duperreanum Pierre , and Lagerstroemia Tomentosa C.Presl

     Important plants in the forests include Dalbergia cultrata,  Vitex peduncularis Wall.ex Schauer , Casearia grewiifolia Vent, Millettia leucantha Kurz, Zollingeria dongnaiensis Pierre, Rosewood, Javanese Cassia, Anogeissus acuminata (Roxb. ex DC.), Lagerstroemia duperreana Pierre ex Gagnep , Lagerstroemia duperreana Pierre, Cratoxylum formosum (Jacq.) Benth , Cratoxylum formosum, Bridelia retusa (L.) A.Juss, Indochinese Milla, Polyalthia viridis Craib, Paranephelium xestophylum Miq, Cananga latifolia (Hook.f. & Thomson) Finet & Gagnep, and Dillenia parviflora Griff. The lowest level at 10 - 15 meters high is home to important plants such as Millettia brandisiana Kurz, Blackwood, Lagerstroemia venusta Wall, Fernandoa adenophyla (Wall. ex G.Don) Steenis, Garuga pinnata Roxb, Cratoxylum formosum, Larus brunnicephalus, Alangium salviifolium (L.f.) Wangerin, Sterculia guttata Roxb, Star Gooseberry, Thyrsostachys siamensis Gamble, Melocalamus compactiflorus, Broken Bones Tree, Buchanania lanzan Spreng, Aporosa villosa (Wall. ex Lindl.) Baill, and Bauhinia glauca.
          The forest floor consists of the seedlings of the larger trees and other plant species such as Bandicoot Berry, Boesenbergia pandurata (Roxb.) Schltr., Pueraria candollei Graham ex Benth. var mirifica, Asiatic Bitter Yam Dioscorea myriantha Kunth, Harrisonia perforata (Blanco) Merr, Senegalia megaladena, Rauwenhoffia siamensis (Scheff) Ban, Elephant Yam, Peacock Ginger, Benghal Dayflower, Bauhinia involucellata Kurz, Siam Weed, and Crape Ginger.
          The survey of plant species in the mixed deciduous forest was carried out using 13 plots measuring 10 x 10 meters. It discovered that this forest covers about 50% of the forest area. About 73 species of trees were found in total, with an average cross-sectional area of 27.4278 square meters per hectare. It has an average density of 220 tons per hectare.

Dry Evergreen Forest
          Most of the dry evergreen forests in Sai Yok National Park are concentrated in the northern section in Thong Pha Phum and the western section next to Myanmar border, which is relatively humid, at an altitude of 450-600 meters above sea level covering about 28 square kilometers, or approximately 21% of the total area.
The structure of the vertical canopy is divided into 4 levels; the top canopy is about 30-35 meters high and home to Barking Deer's Mango, Dipterocarpus turbinatus C.F., and Jambolan Plum. The second canopy is at 25-30 meters in height and the important plants are Mesawa, Lagerstroemia calyculata Kurz, Dillenia aurea, Needle Wood, and Resin Tree. The third level, at 20 - 25 meters is home to plant  species such as Evergreen Chinkapin and Polyalthia viridis Craib. The canopy of the smaller trees (the forth level) at 15 - 20 meters includes Millettia brandisiana Kurz, Syzygium megacarpum (Craib) Rathakr. & N.C. Naire, Aporosa villosa., and Jambolan Plum.

         The dry evergreen forest floor consists of the seedlings of the larger trees, such as Mesawa, Barking Deer's Mango, Resin Tree, Dipterocarpus turbinatus C.F., and others, such as Bandicoot Berry, Asiatic Bitter Yam, Ground Orchid, Actinoscirpus grossus (L.f.), Dioscorea myriantha Kunth, Harrisonia perforata (Blanco) Merr, Fever Vine, Hyacinth Bean, Peacock Ginger, Benghal Dayflower, Siam Weed, Orchid Tree, and ginger varieties. According to a survey of plant species in dry evergreen forests using 3 plots measuring 10 x 10 meters, it was found that this type of forest has its canopy covering about 65% of total area. A total of 31 species of wood were discovered, with the average cross-sectional area of 8.4 square meters per hectare. It has an average density of 207 tons per hectare.

Deciduous Dipterocarp Forest
           Deciduous Dipterocarp forests are scattered on the southern side of Sai Yok National Park at an altitude of 80 - 400 meters above sea level. They exist in shallow to medium depth soils, and on outcrops and high and steep slopes. They cover an area of about 24.18 square kilometers, which accounts for about 2.52% of the total area.

There are 3 levels, with the highest level at about 20-25 meters. The important plants in this class are Dipterocarpus tuberculatns Roxb, Dipterocarpus obtusifolius, Kenari, Flemingia sootepensis Craib and Bombax valetonii. The second level is at 10 to 15 meters in height, and is home to important plants such as Iron Wood, Indian Laurel, Haldu Wood, Quercus kerrii Craib, Lannea coromandelica (Houtt.) Mer, Great Elephant Apple, Monkey Jack, Croton oblongifolius Roxb, and Aporosa villosa (Wall. ex Lindl.) Baill.

          The forest floor consists mainly of the saplings of the larger trees and other species such as Buchanania lanzan Spreng, Ceylon Oak, Orchid Tree, Bauhinia saccocalyx, Milkey Tree, Palmyra Palm, Yellow Latan Palm, Star Gooseberry, Java Plum, Burma Padauk, Indochinese Milla, Terminalia pierrei, Lagerstroemia duperreana, Antidesma puncticulatum Miq, Dalbergia cultrata Graham ex Benth, and the Metocalamus compactiflorus. The survey in the deciduous dipterocarp forest used 5 plots of 10 x 10 m size. It was found that this type of forest has its canopy covering about 55% of total area, with a total of 33 species of trees, an average cross-sectional area of 11.16 square meters per hectare, and an average density of 434 tons per hectare. 

Wildlife Resources
          There are many wildlife species in the Sai Yok National Park, which were counted using direct count method, as well as indirect method such as photographic sampling and tracking using footprints, droppings, nests, burrows, debris, and other traces made by wild animals. Previous academic works were also examined.

          The survey showed there are at least 294 wildlife species, divided into 220 genera and 102 families, consisting of 58 mammals, 115 wild birds, 36 reptiles, 15 amphibians, and 70 freshwater fish.
The following information pertains to each type of wildlife.
Mammal
Sai Yok National Park contains a total of 58 species belonging to 45 genera and 28 families.

           According to this latest study, 27 species accounted for 46 percent of all mammals when species were counted. Despite the relatively large number of species, the number and likelihood of sightings are low due to encroachment by humans for farming and former timber concessions.

           Special mammals once found in the area include Schomburgk’s deer and Cervus eldi ( C.eidi). According to Guehler (1933), citing the testimony and photographic evidence of Mr. Luang Wisit, Kanchanaburi mayor, stated in 1932, that someone shot a male Schomburgk’s deer from a herd of Cervus eldi on the banks of Khwae Noi River near the Sai Yok National Park Headquarters, which was the last sighting report. However, Stockly (1933) refused to accept the Schomburgk’s deer photographic evidence of as a the genuinue hunt at the time.

      The area is also home to the world's smallest mammal, Kitti Hog-Nosed Bat (Craseonycteris thonglongyai). Its total body length is just 23-33 mm, with a wingspan of 22-26 millimeters and no tail. It weighs just 2 grams.

          Mr.Kitti Thonglongya observed the bat when collecting samples from Khang Khao Cave and Phra Cave in 1973. After conducting a research, he sent some samples to the Natural History Department of the British Museum, where it was found to be a new species. Mr. Kitti died in 1974. Mr.John E.Hill studied structure of the shape and found that special characteristics could not be classified within an existing bat family, so he named the bat after Mr Kitti. The Kitti Hog-Nosed Bat (Craseonycteris thonglongyai) was the first new family of bats in 66 years (Hill 1974) from the last naming of different families by Mr. G.S. Miller in 1907 (Lekagul and Mcneely, 1997).
         The exploration of limestone caves in Sai Yok National Park and adjacent areas totaling 8 limestone caves, only 3  small caves that the Kitti Hog-Nosed Bat (Craseonycteris thonglongyai) can be found from 10 to 62 individuals . The cave has a number of different chambers where bats are found resting, and they preferto hang from the ceiling of the cave or the walls of the small cave, usually in numbers of 1 - 3 bats although 52 bats are found in 1 particular cave. Other bat species that share the caves have different hanging locations. Species include Hipposideros bicolor, Horseshoe Bat (Rhinolophus spp.), and Tomb Bat (Tapozous sp.) 

          From the observation in April and July 1991, the Kitti Hog-Nosed Bat in Wang Phra Cave, which is located on the outer boundary on the southeast side of Sai Yok National Park area went out for food at 19.10 hrs. They fly alone which is different from Black-Bearded Tomb Bat, which departs in group from their resting places in Lo River between 18.35 - 19.50 hrs. The feeding area includes deciduous forests and teak forests. Duangkhae (1990) reported that the Kitti Hog-Nosed Bat emerges for 18 minutes in the morning and 30 minutes in the evening and does not travel more than  a kilometer from the cave, and will not come out at all in low temperatures or if there has been heavy rain. 

          Other mammal species found in the area include wild elephants (Elephas maximus), tapirs (Tapirus indicus), guar (Bos gaurus), and banteng (Bos javanicus ), which are particularly found in Ro Rae Valley, Huai Bong Ti Valley, and into the border mountain ranges. The conditions in the Sai Yok National Park are that of a complex hill forest similar those in Thung Yai Naresuan Wildlife Sanctuary in Kanchanaburi Province. It is mostly deciduous and dry evergreen forests, which are suitable for Asian Elephants and Guar rather than Banteng which they prefer the lower section of Sai Yok National Park and on the west bank of the Khwae Noi River within the Erawan National Park area.   

        The mammals found in the area are classified according to their protected status under the Wildlife Preservation Preservation Act B.E. 2503 (1960). At the moment, only one species of most protected wildlife catagory 1 resides in the park, which is the Serow (Capriconis sumatraensis).
        According to Ministerial Regulation No. 14 (1985) issued under the Wildlife Preservation Preservation Act, B.E. 2503 (1960), this area contains a total of 26 species or 45% of Endangered species including Clouded Leopard (Neofelis nebulosa), White-Handed Gibbon (Hylobates lar), Three Prebytis genera, and Asian Golden Cat (Felis temminckii). 

          There are 11 protected wildlife in category 2 which account for 19% of mammals found. They include  Burmese Hare (Lepus peguensis), Sun Bear (Helarctos malayanus), Asian Black Bear (Selenarctos thibetanus), Indo-Chinese Leopard (Panthera pardus),  Bengal Tiger (Panthera tigris), Lesser mouse-deer (Tragulus javanicus), Indian Muntjac (Muntiacus muntjak), Fea's muntjac (Muntiacus feae), Sambar Deer (Cervus unicolor), Gaur (Bos gaurus) and Banteng (Bos javanicus).
Wild birds
           The survey result and report review showed that birds found in Sai Yok National Park were not less than 115 species from 90 genera in 38 families, of which 103 were directly observed during operations in the area. Self-study nature trail survey (Wittaya, 1996) investigated the the area's characteristics, soil cover, and ecosystems, and found it to be similar to Thung Yai Naresuan Wildlife Sanctuary in Kanchanaburi Province. The actual number of species may be over 250 so further exploration is necessary. Several other important species may be found. The bird list is based primarily on Lekagul and Cronin (1974).

          The birds that appear in Sai Yok National Park area can be classified into 104 species of protected wildlife in Category 1 (90% of all birds). Important wild birds found were Kalij Pheasant (Lophura leucomelanos), White Peacock Pheasant (Polyplectron bicalcartum), Thai Peacock (Pavo mutrcis) (found In 1990 in mixed deciduous forests along the banks of Lo River branch of Noi River), Wreathed Hornbill (Rhyticeros undulatus), and Oriental Pied Hornbill (Anthracoceros albirostris).

      Among the birds listed as protected wildlife in Category 2, there are only four (accounting for 4% of the total number of birds found), including Green-Legged Partridge (Arborophila chloropus), Red Junglefowl (Gallus gallus), Hick-Billed Green Pigeon (Treron curvirostra) and Mountain Imperial Pigeon (Ducula badia). Additionally, seven species of birds were found (accounting for 6% of all birds that are not protected by law).

Reptiles
         Reptiles often live in forests and water sources within Sai Yok National Park. There were at least 36 species from 31 genera in 12 families, 21 of which were directly identified during the study (58 percent of all reptiles found), and 15 were documented by Smits (1916,1965,1970). An interesting species of reptile that was once observed in Kwai Noi River near Sai Yok is Siamese Crocodile (Crocodylus siamensis), which was more common in the past (Smits,1919). During the year 1971, residents of the Kwae Noi river frequently ecncountered freshwater crocodiles at Pralom Beach, Wang Phra Cave, and in Noi River to Phra Pu Cave entrance. Later, crocodiles were hunted and their numbers have reduced to the point where they may be extinct in the area.

         A total of 17 important and legally protected wildlife are in Category 1, representing 19 percent of the total reptiles found, including Big Headed Tortoise (Platysternon megacephalus), which was described by Taylor in 1970. The tortoises are found near bodies of water, streams, and in hillside forests.
There are two protected  wildlife in Category 2 (6% of all reptiles) both of which are pythons. The northeastern, northern and western Sai Yok National Park sites are considered the southern end of the scatter. The Asian Forest Tortoise (Teatude emys) and Elongated Tortoise (Tetragnatha elongata) are the most common in this area but other reptiles include Draco blanfordi, D.verssicolor, and Red Tailed Green Ratsnake (Gonyosoma oxycephalum )

          Additionally, another 27 species (representing 75% of the reptiles) were found. A rare and interesting species includes Siamese Narrow-Headed Softshell Turtle (Chitra indica), which is one of the largest turtle species in Thailand. It can be found in Khwae Noi, Khwae Yai, and Mae Klong rivers. Occasionally, fishermen in this area see them, mainly during the spawning season on the sandy shores.

Amphibians
         This animal is another cold-blooded vertebrate, of which there are no less than 15 species in, 6 genera, 4 families. Ten species (67% of total amphibians found) were seen during the research and sampling period. The others are known from the paper by Taylor in 1962. 

         Amphibians found in the area are mainly from the Ramidae family, such as Puddle Frog (Occidozyga lima), Green Paddy Frog (Rana erythiaea), Asian Grass Frog (Rana limnocharis), Dark-Sided Chorus Frog (Rana nigrovittata), and Giant Asian River Frog (Rhinophis blythii), which is the only amphibian in the protected wildlife in Category 2. 

         Protected wildlife Category 1 includes members of Toad family, including 3 types of Bufonidae, whichs account for 20% of all amphibians found, namely Asian Small Toad (Bufo parvus), Grey Cave Toad (Bufo macrotis) and Giant Jungle Toad (Bufo asper). Members of the Rhacophoridae Family also reside there, including Malayan Flying Frog (Rhacophorus leucomystex), Microhylidae Family Striped Sticky Frog (M.ornate), and Asian Painted Frog (Raloula pulchrs), which are found quite easily during rainy season. 

Freshwater Fish
      The Mae Klong River,Khwae Noi, and Khwae Yai River contain over 130 types of freshwate fish species according to a 1980 report by the Inland Fisheries Research Insitute.
Except Mae Klong river, the freshwater fish species are most found here, while Chao Phraya River has 127 species, Mun River has 116 species, Bung Boraphet has 103 species, Ubolratana Dam reservoir has 94 species, and Phayao Lake has 57 species.

          The Sai Yok National Park receives significant amounts of water from the Khwae Noi River and various other waterways , such as the Khwae Noi River  Sai Yok Creek,  Bong Ti Creek, and others. The Khwae Noi River is home to at least 70 fish species belonging to 48 genera and 20 families. The area's sample contained 17 species, accounting for 24% of the total known, with the others known from the Johnsen report (1963, 1964 a,b) and from the Smith paper (1945).

          Most of the fish are found to belong to the Cyprinidae family, which was 37 species , accounting for more than half of the fish species in the hKwae Noi River. These include Celtrops, Oxygaster, Paralaubuca, Rasbora, Danio, Soldier River Barb (Amblyrhyn chinchthy truncates), Hampala Barb (Hampala macrolepidota), Sultan Fish (Leptobarbus hoevenii), and other bards. Another family of fish found is Dusky-Hairfin Anchovy (Setipinna mela), Yellow Mystus (Mystus nemurus ), and Banded Leafish (Pristolepis fasciayu).