South of the main road, the park is long and thin; and stretches about 190km southwards, although it is only about 85km wide at its broadest point. On the park's eastern boundary is the Kafue River and the Itezhi-Tezhi Dam: 300km2 of water. Itezhi-Tezhi differs from many dams as, apparently, it is not made of continuous concrete but instead is filled with earth, in order to render it less vulnerable to tremors and minor earthquakes.
The vegetation and geography of the southern side are similar to the north though there's more Kalahari sand in the south, and it's notable for a few really beautiful teak forests.
The demise of the teak forests
Between two junctions, (GPS: J07 and GPS: J08), is a fairly clearly signposted track that is seldom driven. This is a shame, as it weaves its way through the beautiful and intriguing Ngoma Forest. This is a dense stand of mature trees which are largely Zambezi teak, Baikiaea plurijuga
(previously called Rhodesian teak) – a tree that occurs only in undisturbed areas of Kalahari sand in northern Botswana, northern Namibia, southern Angola and southwest Zambia.
These reach up to 20m in height, with a dense, spreading crown of leaves, and smooth, grey-brown bark. The trees flower from December to March, bearing lovely pinky-mauve flowers. Seedpods follow, from June to September, cracking open explosively to catapult their seeds a distance to the ground.
The tree's wood is dense and hard, but also very even-grained and strong. It's never had many traditional uses, as it was too hard to cut, but was a sought-after timber that was (and sadly is) commercially very valuable. It's been widely used for bridge-building and railway sleepers, and Palgrave reports that 'when the London corn exchange was rebuilt in 1952 a special grooved floor was designed to take the grain thrown down by the merchants, and B. plurijuga
was selected for the parquet blocks because of its ability to withstand abrasion without splintering'.
Stands of this forest probably covered fairly large areas of the Kalahari, and certainly of southwestern Zambia. Now it's severely threatened, and its demise is typical of that of several other hardwood species that were once common here, like mukwa, Pterocarpus angolensis
, and rosewood, Guibourtia coleosperma
has been commercially logged in Zambia since around the start of the 20th century. Zambian timber production probably peaked in the 1930s, but by the 1960s huge tracts of teak forest had been lost. Now the export of Baikiaea logs is banned. However, licences are still being given out to sawmills to export Baikiaea timber, predicated on (difficult to enforce) promises to leave a minimum number of the trees, and then not log the same area for 20 years.
Meanwhile, experts suggest that a 300-year cycle would be needed to allow the forests to regenerate. They note that fire is often used as a tool by loggers, to open up the dense under-storey of vegetation (known as mutemwa) in B. plurijuga
forests, and that the debris left behind after logging will often lead to fires. Baikiaea plurijuga
is particularly sensitive because its thin bark renders it very susceptible to fire; once burnt, these forests degrade forever and don't recover.
In recent years the poverty in the area, combined with major commercial pressures, has led to many of Zambia's remaining 'forest reserves' being degazetted, which then opens them up for commercial logging. So, sadly, a beautiful teak forest like Ngoma is an increasingly rare sight.