Each September the tree in our garden presents an amazing spectacle. Within just two weeks its bare branches are transformed into a crown of bright green leaves and wine-coloured flowers.

This month the flowering coincided with having to house-train a puppy, which required several trips outside in the evening. That’s when I noticed the startlingly fresh night-time fragrance of the Sausage tree. It wasn’t sweet, but nor was it unpleasant. Scientists have a name for it: chiropterophilous, that is, attractive to bats. But here’s the odd thing: recent research states that while there’s published evidence for bat pollination of K. africana in West Africa, there’s none in southern Africa. It could be a “lost mutualism”.

My Dad recalls camping beneath a Sausage tree along the banks of the Zambezi during a canoeing trip in the 90s. All night long bats visited the tree, and the flowers plopped down among the campers. Looking back, my Dad says it’s unclear whether the bats were feeding on the flowers or just using the tree as a feeding site.  There is a difference.

Reay Smithers, in his book The Mammals of the Southern African Sub-region, says Peters’ Epauletted Fruit Bats, Epomophorus crypturus, are attracted to the Sausage tree because it has thin branches that can be easily clasped while they devour food gathered elsewhere. The tree’s thick foliage also gives them protective cover while they feed.

Bees visited the flowers too, but they didn’t touch the stigmas. Not a single bat was seen visiting the flowers, according to the team who published their paper last year in the journal Koedoe.

If birds have replaced bats as pollinators, seed dispersal — via that amazing sausage-shaped fruit — appears to be limited.

Hippos are known to eat the fruit, which might account for germination of Sausage trees alongside rivers. And Smithers says that black rhinos feed on them too, while baboons chew open the pods to get at the pith and the seeds.

But in the Kruger study, Sausage tree fruit placed beneath the trees and monitored by the scientists was left untouched, apart from the odd desultory sniff from a passing elephant.

“Dispersal limitation may be a part of the recruitment bottleneck,” the team wrote, noting a significant lack of young Sausage trees in their study area.

It’ll be a sad day if the only specimens that remain are the ones cultivated by man. After all, everyone has a story to tell about the tree.

Last year a Harare businessman I met told me how several years ago, on a visit to Mana Pools, he parked his brand new pick-up truck beneath a Sausage tree. During the night there was a loud clunk and in the morning he inspected the damage: a large dent in his shiny new bonnet.

He returned to Harare a wiser man having learned that falling sausage tree fruits, like falling coconuts, can be a serious hazard.

Ryan Truscott

Water was essential and there was a well, the area was cleared as it had been a field of tobacco, which had had a bad infection of nematodes. So there were no trees. I often remember my mother sadly saying how she would have loved some Msasas in the garden, but she never considered trying to grow them.

Now it was important to plant trees, so with advice from friends they planted fast growing exotics: Toona ciliata, Jacarandas, a Syringa, Melia azedarach, a Delonix regia, the Flamboyant, a Pride of India, a circle of Poinsettias, Euphorbia pulcherrima round the drive in the front which measured a fifth of a mile.

Not long before we left I planted a Calodendrum capense. Behind the tennis court we planted a Bridelia micrantha, the autumn leaves would have been spectacular in a few years.

We had some interesting trees just outside the fence, a grove of Burkea africana, a Pterocarpus rotundifolia which flowered profusely every January for a short week. The snake bean tree Swartzia madagascariensis, the horn-pod tree Diplorhynchus condylocarpon and Acacia  amythethophylla and Azanza garckeana the snot apple tree.

When Jim left the Forestry Commission as chairman he was given a Ginkgo biloba the maidenhair tree. This was very slow growing but may have done better on red soil where it was better watered.

Its pollination has been extensively researched in the Arabuko-Sokoke forest on the coast of Kenya some 110km north of Mombasa.  I am familiar with the forest because research work was conducted by my father. He was testing different tsetse fly attractants using traps. The forest with its diversity was a source of wonder and amazement.  The biodiversity of the forest is large and even has rare mammal species.

The forest is now protected and commercialised because local people are allowed to gather honey.  Bees are the main pollinators gathering either pollen in their pollen baskets or nectar.  The bees communicate the source of nectar or pollen to the other workers in the hive by a dance using direction from polarised light. Karl von Frisch found that bees perform a waggle dance on the hive to alert other worker bees to the direction and distance of a source of food. It has been recently discovered by researchers at Bristol University that bees use their ability to see polarized light when foraging. Light reflected from downward facing flowers contrast with the skylight polarization patterns helping the bee to identify a specific flower.

Not only do bees communicate the source of food they can navigate and pinpoint a specific flower or flowers. Polarized light is caused by air molecules from the atmosphere scattering protons. This is one way directional and creates a highway of light. With this superior ability bees must be the main pollinators of Brachystegia spiciformis. The evidence is that in many areas honey is collected in abundance from where these trees occur. This is predominantly Miombo Woodland. The literature has references to collecting honey from wild and traditional hives in the Nilsa National Reserve in Mozambique, in coastal forest conservation in Tanzania and Kenya. There are references to Zimbabwe and Zambia. Wherever Brachystegia occurs, bees are the primary producers of honey.

The bee is the African variety of honey bee Apis mellifera scutellate.  Stranger bees belonging to the Meliponini have also been recorded. Bee keeping also plays a role in the conservation of forests.

The main tree species of the Miombo Woodland are predominantly Brachystegia spiciformis, Julbernardia globiflora which are dominant. Other species are Pterocarpus angolensis and Albizia sp. The sequence of flowering amongst the trees and other flowering plants is staggered. Julbernardia flowers January and Brachystegia as late as August.

Bees with their communication, navigation and directional skills are well adapted for pollen and nectar collection. Butterflies are also pollinators. The main genus are the Charaxes recorded in Zimbabwe and Kenya in the Arabuko-Sokoke Forest.

Butterfly farming for the sale of pupae has generated income for families living in the area of the Arabuko-Sokoke Forest. As pollinators they too are considered to play an important role in the conservation of the forest.

After dark moths and bats play their role as pollinators and conservationists of the Miombo Woodland. Moths are attached to pale or white flowers. Brachystegia flowers are pale green with white stamens. The flowers are fragrant and have liquid nectar both prerequisite for the feeding of moths and bats. Moths especially hawk moths have a long proboscis for sucking up nectar.

Current research from Newcastle University has shown that moths pollinate a wide range of plants and that they work harder than their dayshift counterparts. They carry pollen on their furry bodies.