As with animals, each species of plant has its favourite conditions. External factors determine where each species thrives, and where it will perish. These include temperature, light, water, soil type, nutrients, and what other species of plants and animals live in the same area. Species with similar needs are often found together, in communities which are characteristic of that particular environment. Zambia has a number of different such communities, or typical 'vegetation types', within its borders – each of which is distinct from the others. The more common include:
Where they haven't been destroyed or degraded by people, woodlands cover the vast majority of Zambia, with miombo being especially common. Because the canopies of the trees in a woodland area don't interlock, you'll generally find them lighter and more open than the country's relatively few forested areas. The main types of woodland found here are:
The dominant tree here is the remarkably adaptable mopane, Colophospermum mopane
, which is sometimes known as the butterfly tree because of the shape of its leaves. It is very tolerant of poorly drained or alkaline soils, and those with a high clay content. This tolerance results in the mopane having a wide range of distribution throughout southern Africa; in Zambia it occurs mainly in the hotter, drier, lower parts of the country, including the Luangwa and Zambezi valleys.
Mopane trees can attain a height of 25m, especially if growing on rich, alluvial soils. These are often called cathedral mopane, for their height and the graceful arch of their branches. However, shorter trees are more common in areas that are poor in nutrients, or have suffered extensive fire damage. Stunted mopane will form a low scrub, perhaps only 5m tall. All mopane trees are deciduous, and the leaves turn beautiful shades of yellow and red before falling in September and October.
Ground cover in mopane woodland is usually sparse; just thin grasses, herbs and the occasional bush. The trees themselves are an important source of food for game, as the leaves have a high nutritional value – rich in protein and phosphorus – which is favoured by browsers and is retained even after they have fallen from the trees. Mopane forests support large populations of rodents, including tree squirrels, Peraxerus cepapi
, which are so typical of these areas that they are known as 'mopane squirrels'.
Without human intervention, the natural vegetation of most of Zambia (about 70%) is miombo woodland and its associated dambos. This exists on Zambia's main plateau and its adjacent escarpments, where the acid soils are not particularly fertile and have often been leached of minerals by the water run-off.
Miombo woodland consists of a mosaic of large wooded areas and smaller, more open spaces dotted with clumps of trees and shrubs. The woodland is broadleafed and deciduous (though just how deciduous depends on the available water), and the tree canopies generally don't interlock. The dominant trees are Brachystegia, Julbernardia
species – most of which are at least partially fire-resistant. There is more variation of species in miombo than in mopane woodland, but despite this it is often known simply as 'Brachystegia
woodland'. The ground cover is also generally less sparse here than in mopane areas.
The word 'munga' means thorn, and this is the thorny woodland which occurs when open grassland has been invaded by trees and shrubs – normally because of some disturbance like cultivation, fire or overgrazing. Acacia
(bearing single-winged seeds) and Combretum
(bearing seeds with four or five wings) are the dominant species, but many others can be present. Munga occurs mainly in the southern parts of Zambia.
In most equatorial areas further north in Africa, where rainfall is higher, forests are the norm. However, there are a few specific ecological niches in Zambia where you will find forests – distinguished from woodlands by their interlocking canopy. These are:
In a few areas of southwestern Zambia (including the southern part of Kafue National Park), the Zambezi teak, Baikaea plurijuga
, forms dry semi-evergreen forests on a base of Kalahari sand. This species is not fire-resistant, so these stands occur only where slash-and-burn type cultivation methods have never been used. Below the tall teak is normally a dense, deciduous thicket of vegetation usually referred to as 'mutemwa
', interspersed with sparse grasses and herbs in the shadier spots of the forest floor.
Moist evergreen forest
In the areas of higher rainfall (mostly in the north of Zambia), and near rivers, streams, lakes and swamps, where a tree's roots will have permanent access to water, dense evergreen forests are found. Many species occur, and this lush vegetation is characterised by having three levels: a canopy of tall trees, a sub-level of smaller trees and bushes, and a variety of ground-level vegetation. In effect, the environment is so good for plants that they have adapted to exploit the light from every sunbeam.
This type of forest is prevalent in the far north of the country, especially in the Mwinilunga area. However, three more localised environments can give rise to moist evergreen forests in other areas of the country.
Riparian forests (often called riverine forests) are very common. They line many of Zambia's major rivers and are found in most of the national parks. Typical trees and shrubs here include ebony (Diospyros mespiliformis
), mangosteen (Garcinia livingstonei
), wild gardenia (Gardenia volkensii
), sausage tree (Kigelia Africana
), Natal mahogany (Trichilia emetica
), and various species of figs. But walk away from the river, and you'll find riparian species thinning out rapidly.
Montane forests are found on the lower slopes of mountains, where the rainfall is high. The Zambian slopes of Nyika Plateau are probably the best example of this kind of vegetation.
Finally swamp forest occurs near to some of Zambia's permanent swamps. Kasanka National Park probably has the country's best, and most accessible, examples of this.