THE QUIVER TREE FOREST ON GANNABOS
The biggest quiver tree forest in the southern hemisphere is been found here, on the farm Gannbos. The quiver tree or "Kokerboom is one of the most interesting and characteristic plants. The plants are usually found growing single but in some areas the plants grow in larger groups, and giving the effect of a forest, like on the farm Gannabos.
Actually it is no tree, but an aloe plant. The botanical name is ALOE DICHOTOMA. Aloe dichotoma is one of three quiver tree species, the other being Aloe pillansii (Giant quiver tree) and Aloe ramosissima (Maiden quiver tree).
The plant is called a "Kokerboom" because some Bushmen and Hottentot tribes used the tough, pliable bark and branches to make quivers for their arrows.
Dichotoma refers to the forked branches of the plant.
Because the quiver tree is an aloe, it has fibrous wood. Like all succulents it has developed specialized way of living in areas of erratic and little rainfall. The quiver tree soaks up water and stores it in its succulent leaves.
Quiver trees prefer rocky, well drained soil habitats and occur in summer and winter rainfall regions. The common quiver tree has a broad distribution through the Northern Cape and Namibia, whereas the sister species are restricted to the Richtersveld in Namaqualand.
People cut the trunks into squares and used them to construct walls. Water was then fed into the fibrous wood from a tank placed at the top.
The trees in the forest are natural. No trees have been planted by humans.
Dating quiver tree age through trunk growth rings as with other trees are impossible due to the soft, fibrous center. Age estimates from growth rates range between 150-250 years for the common quiver tree and more than 380 years for the Giant quiver tree. With only periodic successful recruitment events we as humans only have a very small window during our lifetimes to view quiver tree life cycles. The potential impacts of climate change, such as reduced rainfall or more erratic rainfall events on populations are therefore difficult to assess. Scientists are attempting to circumvent this problem through computer modelling, growth rate monitoring and age estimates.
Various factors that can affect the health of quiver trees. Some are natural, for example porcupines stripping bark from the main stem, baboons breaking branches in the canopy, pest infestation, trees uprooted during strong winds or under their own weight when soil is moist and soft. It is thought that quiver trees can amputate some of their own branches when stressed, for example under long drought conditions, thereby sacrificing a portion of itself in order to survive.
The species Aloe dichotoma has been known to scientists since 1685, when it was discovered during Governor Simon van der Stel's expedition to Namaqualand in search of copper.
The quiver tree is a stout tree up to 9 meters high with a smooth trunk which can be up to one meter in diameter at ground level. The leaves are greyish-green and the flowers are bright yellow.
Quiver trees, like many other plants adapted to arid environments, are dependent on moisture. Population responses to historic and future rainfall will be investigated. Although pests such as aphids and utilisation by porcupines and other large mammals may affect a tree, land management practices may also be influential. It is therefore important to understand all the pressures the quiver trees are exposed to for a proper understanding of the species.
It is often encountered growing at the most precarious positions, such as on the edges of canyons, possibly relishing the cool updrafts of wind. The rocks anchor the plants which have a spread-root-system.
They have their first flowers when they are about 15 to 25 years old. The flowering-season is in the winter during May, June and July.
Swarms of birds and locusts are drawn by the sweet nectar of the quiver tree's flowers, and baboons have been known to strip off the blossoms in search of the liquid.
Sunset in the forest.