In pictures: Zanzibar's clove harvest

The archipelago of Zanzibar in Tanzania, sometimes known as the Spice Islands, was once the world's largest producer of cloves. It is still an important industry for farmers on the island of Pemba as the BBC's Ruth Nesoba found out during the harvesting of the flower buds which when dried are used as a spice in cooking, to flavour drinks like mulled wine and in medicine.

The months of September, October and November are the crucial time of year for clove farmers on Pemba. It is the period of the short seasonal rains when the cloves are harvested by hand. Bunches on lower branches can be pulled off or shaken free.

Harvesting is strenuous work. The bunches of cloves can be tucked away in dense foliage where they are difficult to get at.

Clove trees can grow up to 15m (49ft) high. Farmers are often skilled climbers, scaling the trees to pull bunches off higher branches. Many people on the island depend on cloves for their livelihood. That has been the case since the trees were introduced from Indonesia around the turn of the 19th Century.

Here at Konde village, as in much of Pemba, every family member is expected to help. Men, women and even young children get up early to help pick the cloves. Scaling the trees is generally left to the men, while women and children gather the cloves that fall to the ground.

The picked flower buds and leaves are carried in a gunny sack from the farmers' land to the villages. The crop is then sorted to separate the leaves from the buds. Both are left to dry in the sun. The dried leaves are crushed and can be used in perfumes and fragrances. They are also used in an oil which can have sanitary applications and is sometimes used in dentistry.

The buds are dried on mats in the sun. At this time of year one often sees mats covered with drying cloves lying by the roadsides. The cloves are left out for about three days. As they dry, they release a sweet, heady aroma, which wafts throughout the island.

The cloves are then carried to the collection centre. There are three government-run collection centres in Pemba. Farmers from Konde take their crop to Chake Chake.

Here the cloves are sifted by hand to remove dirt and other unwanted particles. It is a thorough procedure intended to ensure that the final product is of high quality.

The sifted cloves are then laid out where they can be checked for quality and tested.

The final crop of dried cloves is then weighed. Each farmer is paid immediately. For every 90kg (198lb) sack a farmer receives $720 (£460). A 1kg bag fetches $8.

The heaviness, dryness and smell of the cloves are checked. Indonesia is the biggest grower, importer and consumer of cloves, producing between 60,000 and 80,000 tonnes a year. But Zanzibar cloves from Pemba are in great demand, says Suleiman Jongo the deputy director of Zanzibar State Trade Centre.

"The cloves have a very strong aroma and the majority of the flower buds are large and intact, making them among the best in the world," Mr Jongo says.

The cloves are put in sacks and taken to the warehouse awaiting transportation to the packaging centre from which they will either be sold locally or exported for use in cooking, medicines, cosmetics, or clove cigarettes which are popular in Indonesia.