The Tree Of Life - IELTS Reading Answers & Explanations

You should spend about 20 minutes on Questions30-40, which are based on Reading Passage 3 below.

The Tree of Life

A. The baobab tree has a very distinctive appearance, with a large, round trunk and branches that look like roots reaching into the air. The latter gained it the name of the 'upside-down tree' but it is also known by other names. The origin of the word 'baobab' is not clear; it may come from the Arabic bu hibab, referring to a fruit with many seeds, or from the medieval Latin bahobab, apparently from a central African language. It grows in arid regions of the southern hemisphere and has evolved unique ways of surviving in water-scarce environments. The tree is common throughout sub-Saharan Africa, Madagascar and north-western Australia. It is impressive, not just because of its appearance and ability to survive in harsh climates, but also because of its size. In Zimbabwe, one baobab grew so big that 40 adults could fit inside it. A baobab can grow 25 metres high and as it gets older, the middle of the trunk becomes hollowed out. The hollow trunk is used as shelter by animals, and humans too have used it for a variety of purposes; one tree was even used as a prison cell. Indeed, the baobab is one of the biggest flowering plants in the world and produces fruits that are prized by people and animals alike for food.

B. Baobabs are long lived but unlike other trees, it is very difficult, if not impossible, to discover their age by counting annual growth rings in the trunk because their growth rings are very faint. Instead, researchers use radiocarbon dating to analyse samples from trees. The oldest specimen found so far was 2,500 years old. The trees have a staged growth pattern that was observed by the naturalist Von Breitenbach, who described four phases. The first is the young or sapling phase, which lasts until the tree is 15 years old. During this phase, it reaches a height of about six metres. The second phase is the cone phase, which lasts until the tree is 60-70 years old. This is the period when growth is the fastest and the tree reaches about 15 metres in height. In the third phase, the bottle phase, the trunk broadens out to produce the tree's iconic shape, and at 200-300 years old, it gains a height of about 20 metres. During the old age phase, the trunk expands further and becomes hollow. The tree eventually dies aged 500-800 years, although some individuals survive much longer.

C. A master of water management, the baobab can hold up to 120,000 litres of water in its trunk, which is incredibly useful for animals and humans in times of drought. Both are able to pierce the tree to access the water, and this is probably why many trees can be found along trade routes in Africa. The trunk is not a single structure but is composed of many stems fused together. This creates gaps in the trunk to capture precious water, which can be absorbed later by the tree - unless people or animals find it first.

D. The tree first flowers after 20 years of age and the flowering period can be up to 6 weeks. The flowers appear in early summer (October to December in the southern hemisphere) and they are extraordinary. White in colour, heavy and large, they open during the evening simultaneously and survive for just 24 hours. When they open, they have a sweet smell but the scent becomes unpleasant later on as they turn brown and then fall. The flowers are pollinated mainly by fruit bats, which are attracted by the strong smell, and to a lesser extent by bushbabies as well as various insects. After flowering, the baobab produces large fruit pods about 20 centimetres long, which hang down from the tree. The pods take six months to ripen before falling to the ground, from where they can be harvested. Inside are small black seeds that are covered with a white powdery substance that tastes lemony and delicious and is a valuable food source. The fruit has many uses: it can be made into a drink that is high in vitamins C and B2, and it has been used to treat fevers; the seeds are pressed into oil or roasted as snacks; and the shell can be made into a musical percussion instrument.

E. Like many giant trees, an old baobab creates its own ecosystem. It supports the life of thousands of creatures, from the largest mammals to insects and other small animals that shelter in its crevices. Birds nest in its branches; baboons eat its fruit; bushbabies and fruit bats drink the nectar. Little wonder the baobab is sometimes called the 'tree of life'. However, like all living things, the baobab does eventually die and when this happens, it collapses quickly and disintegrates into fibres. Perhaps this has given rise to another of its names, the 'magic tree'; its disintegration is so fast that the tree simply seems to disappear.