While we often think of orchids as growing in rainforest canopies, there are thousands of terrestrial orchid species that grow in the ground. Many of these produce edible tubers that have been harvested for hundreds of years.
In Turkey, these orchid tubers are used to make salep, which is used in the ice cream and beverage industry, and in Zambia tubers are used in a food called chikanda.
However, most of these tuberous orchids normally produce only one tuber each year which means that they are rarely cultivated to feed the commercial trade for these products. This means that most are collected instead from the wild.
Many tuberous orchids are now under threat of extinction despite the national and international treaties in place to protect them. This pushes the need for sustainable production of these terrestrial orchids, but is this possible?
Tuberous orchids are often harvested in the eastern Mediterranean, including Turkey which hosts one of the Mediterranean's richest orchid flora--in Turkey alone you will find 24 different orchid genera and 187 species and sub-species of the orchid family. Despite the ban on collecting wild orchids, an estimated 500-600 tons of fresh salep tubers (equivalent to 120,000,000 orchids) are used in Turkish markets each year. The lack of alternatives for producing salep in a more sustainable way means illegal collection and trade of these orchids is likely to continue.
There has been long debate about the environmental and commercial sustainability of this ancient trade. A recent study by Caliskan et al. (2019) experimented with a new propagation method for one of the species affected by commercial salep trade--Ophrys. sphegodes subsp. mammosa--to see if sustainable production is possible.
Plants were collected from the wild populations along the Turkish coast line. Normally, this species develop a single new tuber each year while the old tuber is gradually depleted, so the researchers did trials in experimental fields to see if they could encourage plants to develop a second tuber each year. They found that many orchids do, in fact, have the ability to develop second tubers, even reaching normal size at flowering. Plants harvested at the beginning and middle of the flowering period had much more success than those harvested at the end. In fact, 96% of these plants did not develop a new tuber when re-planted, likely because these were close to the end of the growth season.
For the first time, these researchers managed to successfully show a new approach to propagation of tuberous orchid, and a possible approach to reduce the impacts of wild harvest. In particular, they advise farmers and harvesters to collect one tuber when the plants first start to flower, and then re-plant the remaining tuber so that they can produce new ones by the end of the season. This may help to make production more viable, and reduce over-collection from natural populations in the longer term. However, until such methods are widely adopted, illegal collection and destruction of these orchids populations is likely to continue.
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