This post will provide some information to understand Vietnam land, it’s good to know before starting a birding trip in Vietnam [update – 10/2022].

Vietnam Satellite Map

Vietnam occupies a total area of 331,699 square kilometers (128,070 sq mi). In comparison, it’s larger than Malaysia but smaller than Japan. Within the Indochinese Peninsula (comprising Vietnam, Laos, and Cambodia), Vietnam’s coastline stretches for 3,260 kilometers (2,030 mi).

Near its coastline, it contains several islands like Phu Quoc, Con Dao, Cham, and Tho Chu Islands. Whereas its disputed islands are the Paracel Islands (Hoang Sa) administered by China as well as the Spratly Islands (Truong Sa) are disputed by China (PRC) and Taiwan (ROC). Overall, the country is a mix of different landscapes like waterfalls, sand dunes, tropical rainforests, sandy beaches, and caves. In fact, it’s home to the world’s largest cave, Hang Son Doong.

Relief

Vietnam’s principal physiographic features are the Annamese Cordillera (French: Chaîne Annamitique; Vietnamese: Nui Truong Son), extending generally from northwest to southeast in central Vietnam and dominating the interior, and two extensive alluvial deltas formed by the Red (Hong) River in the north and the Mekong (Cuu Long) River in the south. Between these two deltas is a long, relatively narrow coastal plain.

From north to south the uplands of northern Vietnam can be divided into two distinct regions—the area north of the Red River and the massif that extends south of the Red River into neighboring Laos. The Red River forms a deep, relatively wide valley that runs in a straight northwest-southeast direction for much of its course from the Chinese border to the edge of its delta.

North of the Red River the relief is moderate, with the highest elevations occurring between the Red and Lo (Clear) rivers; there is a marked depression from Cao Bang to the sea. In the Red River delta and in the valleys of the region’s other major rivers are found wide limestone terraces, extensive alluvial plains, and low hills. The northeast coast is dotted with hundreds of islands composed mostly of limestone.

Compared with the area north of the Red River, the vast massif extending southwest across Laos to the Mekong River is of considerably higher elevation. Among its outstanding topographic features is Fan Si Peak, which at 10,312 feet (3,143 meters) is the highest point in Vietnam. South of the Black (Da) River is the Ta P’ing, Son La, and Moc Chau plateaus, which are separated by deep valleys.

In central Vietnam, the Annamese Cordillera runs parallel to the coast, with several peaks rising to elevations above 6,000 feet (1,800 meters). Several spurs jut into the South China Sea, forming sections of the coast isolated from one another. Communication across the central ranges is difficult. The southern portion of the Annamese Cordillera has two identifiable regions.

One consists of plateaus of approximately 1,700 feet (520 meters) in elevation that have experienced little erosion, as in the Dac Lac Plateau near Buon Me Thuot. The second region is characterized by heavily eroded plateaus: in the vicinity of Pleiku, the Kontum Plateau is about 2,500 feet (760 meters) above sea level; and in the Da Lat area, the Di Linh Plateau is about 4,900 feet (1,500 meters).

Drainage

Roughly triangular in shape, with its northeast and southwest sides bounded by the northern uplands, the Red River delta extends inland some 150 miles (240 km) and runs some 75 miles (120 km) along the Gulf of Tonkin. The delta can be divided into four subregions. The northwestern section has the highest and most broken terrain, and its extensive natural levees invite settlement despite frequent flooding.

The low-lying eastern portion is less than seven feet (two meters) above sea level in the vicinity of Bac Ninh. Rivers there form small valleys only slightly lower than the general surface level, and they are subject to flooding by the area’s unusually high tides. The third and fourth subregions consist, respectively, of the poorly drained lowlands in the west and the coastal area, which is marked by the remains of former beach ridges left as the delta expanded.

The Annamese Cordillera forms a drainage divide, with rivers to the east flowing to the South China Sea and those to the west to the Mekong River. South of the mountain range there is an identifiable terrace region that gives way to the Mekong delta. The terrace region includes the alluvial plains along the Saigon and Dong Nai rivers. The lowlands of southern Vietnam are dominated by alluvial plains, the most extensive of which is the Mekong delta, covering an area of 15,400 square miles (39,900 square km) in Vietnam. Smaller deltaic plains also occur along the south-central coast facing the South China Sea.

Soils

In northern Vietnam the heavy monsoonal rains wash away rich humus from the highlands, leaving slow-dissolving alumina and iron oxides that give the soil its characteristic reddish color. The soils of the Red River delta vary: some are fertile and suitable for intense cultivation, while others lack soluble bases. Nonetheless, the delta soils are easily worked. The diking of the Red River to prevent flooding has deprived the delta’s rice fields of enriching silts they once received, and it has been necessary to apply chemical fertilizers.

There are some two dozen soil associations, but certain soil types predominate. Among these are red and yellow podzolic soils (i.e., soils that are heavily leached in their upper layers, with a resulting accumulation of materials in the lower layers), which occupy nearly half of the land area, and lateritic soils (reddish brown, leached tropical soils), which constitute another one-tenth more. These soil types dominate the central highlands.

Alluvial soils account for about one-fourth of the land in the south and are concentrated in the Mekong delta, as are peat and muck soils. Gray podzolic soils are found in parts of the central highlands and in old terraces along the Mekong, while regulars (rich black loams) and lateritic soils occur in both the central highlands and the terrace zone. Along the coast of central Vietnam are regosols (soft, undeveloped soils) and noncalcic brown soils.

Climate of Vietnam

The northern part of Vietnam is on the edge of the tropical climatic zone. During January, the coldest month of the year, Hanoi has a mean temperature of 63 °F (17 °C), while the annual average temperature is 74 °F (23 °C). Farther south, the average annual temperature in Hue is 77 °F (25 °C) and in Ho Chi Minh City is 81 °F (27 °C); in the highland city of Da Lat, it drops to 70 °F (21 °C).

The winter season in northern Vietnam lasts from November to April; from early February to the end of March there is a persistent drizzle, and March and April are sometimes considered to be transitional periods. The summer in northern Vietnam lasts from April or May to October and is characterized by heat, heavy rainfall, and occasional typhoons. In central and southern Vietnam the southwest monsoon winds between June and November bring rains and typhoons to the eastern slopes of the mountains and the lowland plains. The period between December and April is drier and is characterized by the winds of the northeast monsoon and, in the south, by high temperatures.

Plant and animal life

Vietnam’s vegetation is rich and diversified, reflecting the country’s great range of climate, topography, and soils and the varying effects of human habitation. The forests of Vietnam can be divided into two broad categories: evergreen forests, which include conifers, and deciduous forests. There are more than 1,500 species of woody plants in the country, ranging from commercially important hardwoods, such as ebony and teak, to palms, mangroves, and bamboos. There also are numerous species of woody vines (lianas) and herbaceous plants. In the aggregate, the dense and open forests, savannas, brushland, and bamboo cover approximately half of the country’s total area.

In most areas, the forests are mixed, containing a great variety of species within a given area. Rainforests are relatively limited, and pure stands are few. The nearest to pure forest types are the pines—the three-needled Pinus khasya and the two-needled P. merkusii found in the uplands—and the mangrove forests of the coastal areas.

In the mountainous regions are subtropical species from such genera as Quercus (oak), Castanopsis, Pinus (pine), and Podocarpus. Brushwood, bamboo, weeds, and tall grasses invade logged areas and grow around settlements and along arterial highways and railroads. Between the logged areas and the upland forests are other mixtures of forest types.

A large part of the forest in the central highlands is dense and rich in broad-leaved evergreens and semi-evergreens, some of which yield valuable timbers. Some of this region is still composed of undisturbed (primary) forests. Other types of forests there include secondary forests; open forests, which typically have trees of the family Dipterocarpaceae and species from the genus Lagerstroemia (crape myrtle); mangrove forests; and barren lands of sand dunes with eucalyptus and small, thorny deciduous trees and species from the Casuarina genus of flowering plants. 

Cogon grass (Imperata cylindrica) is commonly found in open forests, and savanna vegetation occupies large areas formerly covered by forests. Grass and sedge swamps are characteristic of the Thap Muoi Plain (Plain of Reeds), a depression in the Mekong delta.

During the Vietnam War, herbicides were used by the U.S. Army to defoliate large areas of forest in southern Vietnam. Most of these forests have been regenerating, but resettlement programs and illegal logging appear to have created longer-lasting damage.

The most common domesticated animals in Vietnam are water buffalo, cattle, dogs, cats, pigs, goats, ducks, and chickens. Wild game in the central highlands includes elephants and tapirs; Sumatran rhinoceroses, believed to have become extinct by the 1960s, were sighted in the 1990s. Also found in the forests are large cats, including tigers, leopards, and ounces (snow leopards); several kinds of wild oxen, including gaurs and koupreys; and various types of bears, among them black bears and sun bears (honey bears).

Deer are plentiful and include the small musk deer and muntjac (barking deer). Other common wild animals are wild pigs, porcupines, jackals, otters, mongooses, hares, skunks, and squirrels, including flying squirrels.

There are also small wild cats, binturongs, and palm civets. Primates such as langurs, macaques, gibbons, and rhesus monkeys live in the forests. Three species of hoofed mammals—the saola, giant muntjac, and Truong Son muntjac—were discovered in the 1990s. Crocodiles are found on the edges of some lakes and along riverbanks; other reptiles include several kinds of lizards, pythons, and cobras. Of the wide variety of land and water birds, some 600 species have been identified in southern Vietnam alone.

References:

Turley, William S., Buttinger, Joseph, Osborne, Milton Edgeworth, Duiker, William J., Hickey, Gerald C. and Jamieson, Neil L.. “Vietnam”. Encyclopedia Britannica, 16 Aug. 2022, https://www.britannica.com/place/Vietnam. Accessed 25 October 2022.