mysterious-african-mistletoes

Mysterious African Mistletoes


Mistletoes are semi-parasites that attach onto trees and shrubs but still retain the ability to produce their own food through photosynthesis. A woodrose is a gall-like outgrowth of host tissue that grows in response to the mistletoe “root” or rather haustorium penetrating through the hosts bark to tap into water and minerals.


Location and description

In the north east of South Africa, in Mozambique and in Swaziland woodroses have been commercialised by rural people. The infected branch is cut from the main tree and the mistletoe parasite is removed. What remains is an attractive flower-shaped woody outgrowth. This may be mounted on a stand, sanded and perhaps varnished and sold as an ornament to tourists. In southern Africa, two mistletoe species (Erianthemum dregei and Pedistylis galpinii), both in the family Loranthaceae are known to produce woodroses. Both mistletoes produce long tube-like flowers that are rich in nectar and feed butterflies and sunbirds. Sclerocarya birrea, the famous marula tree from which traditional African beer is made, is the principal host tree for both mistletoes (Dzerefos et al. 2003).

Impact of harvesting

A survey was conducted in Bushbuckridge, South Africa to examine the harvesting levels and ecology of woodrose-producing mistletoes. Information was collected from harvesters and traders by means of standardised interview schedules and field observations. It was found that harvesting techniques are not detrimental to hosts as only branches supporting mistletoes are cut. Over half the harvesters interviewed reported harvesting both live and dead mistletoes while 20% used only dead ones (Dzerefos et al. 1999).

Prices ranged from US$ 0.40 to 0.45 per woodrose, with higher prices being paid for large or unusually shaped woodroses (Dzerefos et al. 1999) . Each woodrose has a unique form and can be as large as two feet. The larger woodroses are sought after as they fetch higher prices and are produced almost exclusively by P. galpinii. The density of large woodroses could be quickly depleted as it has been calculated that it takes between 40 to 56 years for woodroses to reach medium size (Dzerefos et al. 1999) .

For every two living E. dregei and 1.5 living P. galpinii a dead woodrose is available in nature (Dzerefos et al. 1999) . In fact there are sufficient dead mistletoes in unharvested and harvested areas to satisfy present market demand and this could represent an exciting job creation opportunity in state and privately owned protected areas. Although removal of dead woodroses could reduce the availability of microhabitats for invertebrate species such as woodborers, this would be insignificant as mistletoes that have started to decompose cannot be used to make ornaments and are hence left untouched. Nutrient loss from the ecosystem would also be minimal, as unwanted parts such as bark and mistletoe branches are removed at source.

Recommendations

At present, small scale harvesting is restricted to community areas around settlements. At the levels of utilization monitored the harvesting of only dead mistletoes from community areas and allowing access to previously unharvested protected areas, utilisation of woodroses is sustainable. However, if harvesting levels increase, then to sustain the “industry” into the future, sustainable harvesting quotas need to be determined, especially for P. galpinii. The sustainable use of woodroses can be developed into a win-win model whereby traditional conservation, science and use by people can work together.