Vegetation :

The low population density of Laos (around 20 inhabitants per square kilometre) has enabled a large forest area to be preserved; covering around half the country. These forests, mostly tropical, are usually made up of trees that shed their leaves during the dry season. Less than a third of these forests are still primal forests.
However these forests are in danger because of excessive lumbering in a certain number of areas such as the South and the South-East.
Another danger comes in the form of traditional forest clearing using slash-and-burn methods by certain mountain ethnic tribes, mainly to grow hillside rice but also corn or poppy. Indeed, by more or less forcing these populations to settle in places close to new axes of communication, their farm plots have been reduced resulting in a much shorter fallow-break and therefore insufficient time for the land to regenerate. As an example, in certain resettled Sino-Tibetan minorities the time allowed for the land to lay fallow used to vary between 18 to 25 years in their former territories whereas in their new farmlands it is only between 5 to 9 years. The traditional slash-and-burn methods practised by the semi-nomadic populations over vast areas did not affect the environment in a big way. They do a lot of harm however on a ecological level when they are used by sedentary populations who, as a result of demographical pressures, do not have enough land to allow for a reasonable fallow-break.
The ends of valleys are mostly occupied by paddy fields.
After the rainy season the river banks, which have been fertilised by brought by flood waters, are invaded by farm plots which produce in abundance the vegetables used in Laos cooking.
There are few fruit trees in Laos, most fruits that can be found are imported. However various programmes are aiming to revive certain varieties such as pineapples.

Fauna :

The low population density mentioned earlier has also contributed to the development of a large number of animal species. As such certain species which were practically unknown have recently been sighted, such as the Quang Vu buffalo, or species which were thought to have disappeared such as the koupreys or Sumatra rhinoceros, or else rare species such as the Irrawaddy dolphin (fresh water dolphin) or the Malayan bear.
Of course there are the wild life common to the Indochina area : sambar, gaur, bateng, black bear, civet cat, various kinds of primates (pig-tailed macaques, small panda, douc langur, gibbon, pangolin, ….), reptiles (royal cobra, green snake, Malayan viper, black monitor lizard…) ….
In spite of the deforestation and especially the war along the Vietnamese border (bombings and chemical agents) there are still a number of wild elephants, particularly in the provinces of Attapeu, Champassak or Sayaburi. The leopard, tiger or panther are still present but are becoming extremely rare.
Bird wild life is very varied. Indeed there are still a large number of species (over 400) in isolated places but around inhabited areas intensive hunting (rudimentary gunpowder rifles or cross-bows for men and slings or traps for children) has wiped out the bird populations. It is noteworthy that the public authorities are making efforts to restrict this hunting and that birds are slowly returning to areas close to villages.
Each river or water hole is full of fish, small crustaceans and sundry amphibians. Certain catfish caught in the Mekong river can weigh over 100 kilos.