Both exotic and indigenous forest trees species that provide goods and services such as firewood, fruits, timber, poles, fodder, environmental protection, amenities in individual SADC countries were identified in the country reports.
Both indigenous and exotic tree species are used in agroforestry systems. The species are either deliberately planted or are managed within their natural habitat to improve their productivity. Among the most important indigenous tree species include the African acacias (Acacia erioloba, A. karroo, A. nilotica, A. senegal, A. tortilis), Dichrostachys cineria, Faidherbia albida and Sesbania sesban. Exotic agroforestry species that were identified as important species in some of the SADC countries include Acacia angustissima, Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala, L. pallida, L. diversifolia and Tephrosia vogelli.
Although, practically all tree species could be used for firewood, there is a group of species that is generally preferred. Such species usually burn without excessive smoke and unpleasant odours. The choice of species is however now very restricted in some localities due to unavailability of some of the preferred species in sufficient quantities. Among the indigenous species, the most widely used tree species in the different SADC countries were identified as Acacia erioloba, A. karroo, A. nilotica, B. plurijuga, Brachystegia spp., C. mopane, Combretum spp., Dialium schlehteri, F. albida, J. globiflora, and Terminalia spp. Exotic tree species that are being grown for provision of firewood include Eucalyptus spp., C. cunninghamiana and Acacia mearnsii. Pines and cypresses although often used in areas of high wood deficit are not preferred species. Where, A. mearnsii is commercially grown for its tannin bark, its wood is also used in the commercial production of charcoal particularly in South Africa and Zimbabwe.
In all the country reports, forest tree species were mentioned as important sources of food from their fruits, more so in times of food shortage. Forest tree species also directly provide other edible products such as seed and nuts, gums and resins, root tubers and leaves for vegetables. Indigenous fruits, for example are processed into a variety of products that store well and therefore readily available in periods of food shortage (Campbell, 1987; Maghembe et al., 1984). Some indigenous fruits such as B. discolor, Phoenix reclinata, S. birrea, U. kirkiana and Z. mauritiana are used in the production of alcoholic beverages. The Amarula cream, an alcoholic product developed from S. birrea fruit in South Africa is now marketed in about 50 countries (Ham and Van Eck, 1997). In Namibia, Hailwa (1999) estimated that fruits and beverages exploited annually are valued at N$4.8 million. Although there are more than a hundred indigenous tree species found in the SADC region that produce edible fruits the following species are regarded as the most important in this diverse region: A. digitata, Annona senegalensis, Artabotrys brachypetalus, Azanza garckeana, B. discolor, Cassia petersiana, Dialium schlehteri, Dictyosperma album, Diospyros mespiliformis, Encepharlatos goetzi, Englophton spp. Eugenia capensis, Faidherbia albida, Ficus sycomorus, Grewia spp. Hyphaene petersiana, Kiggelaria africana, Mimusops zeyheri, Parinari curatellifolia, Phoenix reclinata, S. tautenenii, Sclerocaryea birrea, Strychnos madagascariensis, S. cocculoides, S. spinosa, Syzygium cordatum, Tabernaemontana elegans, Tamarindus indica, Trichilia emetica, Uapaca kirkiana, Vangueria infausta, Ximenia spp. and Ziziphus species.
Other than products directly obtained from forest trees, both indigenous and exotic forests are important sources of other non-wood forest products such as edible worms and insects and mushrooms. The most widely exploited worms are those of the Imbrasia genus (I. belina, I. etali and I. zambeziana) commonly found on C. mopane, B. spiciformis and J. globiflora and D. mespiliformis species. Both indigenous woodlands, particularly the miombo and the exotic pine plantations are an important source of mushrooms (Masuka (2002).
In Zambia, 38 indigenous tree species are known to produce tannins, 19 produce dyes and 11 species produce resins and gums. In South Africa, species such as Rumohra adiantiformis and proteas are used in the florist trade. In Namibia non-wood forest products such as beverages are estimated to have an annual economic value of N$1.5 million (US$680 000). Masuka (2002) estimated that mushroom production in Zimbabwes pine plantations was about 807 tonnes annually although only 100 tonnes are harvested annually and exported bringing in some US$1.5 million. In Tanzania, 756 tonnes of bark of Cinchona spp. valued at US$258 000 was exported in 1991 (FAO, 2000). In Namibia, 600 tonnes of Harpagophytum spp. worth US$1.5 to 2 million in 1998 (Hailwa, 1999). In 1992, Zambia produced honey and beeswax amounting to 90 tonnes and 29 tonnes respectively which was valued at US$170 000 and US$74 000 (FAO, 2000).
Several exotic and indigenous tree species are regarded as important fodder tree species. The indigenous tree species cited as being widely used for fodder include the African acacias (A. erioloba, A. karroo, A. nilotica, A. robusta) Atriplex nummularia, Cassia petersiana, C. mopane, D. cineria, F. albida, Julbernadia paniculata, P. reclinata, Piliostigma thonningii, Swartizia madagascariensis and Trema orientalis. Exotic tree species used as fodder include A. angustissima, C. calothyrsus, Ceratonia siliqua, Chamaecytisus palmensis, L. leucocephala, L. pallida, L. diversifolia, Gliricidia sepium, Prosopsis glandiflora, and T. vogelli.
Both indigenous and exotic species provide poles, which are mainly used in building huts, cattle pens, fencing and general farm construction. The most widely used species are Androstachys johnsonii, B. plurijuga, Bivinia jalbertii, Brachystegia spp. C. mopane, Dalbegia melanoxylon, Dialium schlehteri, Hypaene crihata, Syzygium caudatum, Terminalia sericea. The most durable and termite resistant species are the most preferred. Among the exotic species, the mostly widely used species for making poles are C. cunninghamiana, E. camaldulensis, E. citriodora, E. cloeziana, E. grandis, E. nitens, E. stellulata, E. rubita and E. tereticornis. In Namibia, Hailwa (1999) estimated the value of poles used for construction of kraals, hut, fencing, etc at about N$595.6 million (US$59.6 million).
Both indigenous and exotic tree species are used as shade trees. The indigenous species cited as being used for shade are A. erioloba, A. quanzensis, Albizia versicolor, Celtis africana, Olea europaea, F. albida, Halleria lucida, K. anthotheca, Kigelia Africana, S. birrea, Schinus molle and Trichlia emetica. The exotic tree species used for shade and shelter are Toona ciliata, C. cunninghamiana, Eucalyptus spp., J. mimosifolia, Pinus spp. and Thuya orientalis
With the exception of Malawi, which has small areas of exploitable conifers such as W. nodiflora, most of the countries in the region do not have naturally occurring fast growing tree species that could be exploited to meet the regions growing demand for timber, pulp and tannins. The major exotic timber species are C. lusitanica, C. tolurosa, P. elliottii, P. kesiya, P. patula, P. taeda, P. tecunumanii, P. radiata, E. tereticornis, Eucalyptus spp and A. mearnsii. The commercially exploited indigenous timber species include A. quanzensis, Allanblackia stuhlmanii, Amblygonocarpus andongensis, A. johnsonii, B. plurijuga, Balanites maughamii, Cephalosphaera usambarensis, D. melanoxylon, Diospyros spp., E. caudatum, Erythrophloleum suaveolens, G. coleosperma, Juniperus spp., K. anthotheca, Milletia stulmannii, Ocotea spp., Olea capensis, P. angolensis, Spirostachys africana and Swartzia madagascariensis.
There are many tree species that are used in the treatment of a range of ailments. These species vary from country to country. The most commonly used species are Cassipourea malosana, Cassia abbreviata, Dioscorea sylvatica, Diplorrynchus condylocarpon, Erythrophleum lasianthum, E. suavoelens, Erythrina abysinica, Harpagophyton procumbens, Ocotea bullata, Warbugia salutaris. The value of medicinal plants in Namibia is estimated at US$3.2 million (Hailwa, 1999). In Mauritius, over 90 indigenous trees and shrubs are used for medicinal purposes. The traditional medicine industry in South Africa is estimated at between US$50 million and $100 million annually (DWAF, 1997).
Both indigenous and exotic species are being used as amenity trees. Among the commonly used indigenous species are Acacia xanthophloea, Anthocleista grandiflora, Bauhinia galpinii, B. petersiana, Celtis africana, Dodonea viscosa, Juniperus procera, K. anthotheca, Schinus molle, Senna siamea, Trochetia boutoniana and Trichlia emetica. Exotic tree species that were identified as being used as amenity trees in the SADC countries were C. cunninghamiana, C. tolurosa, C. lusitanica, Gmelina arborea, Jacaranda mimosifolia, Pinus spp., Melia azedarach and Salix babylonica. Most of these amenity tree species are either planted in gardens, along avenues in urban centres or as hedges.
Both indigenous and exotic forest trees are used for environmental protection such as gully reclamation, restoration of degraded sites, fixing shifting dunes, etc. The commonly used indigenous tree species include African acacias (Acacia erioloba, A. nolotica and A. tortillis), Atriplex nummularia, Burtt davyanyasica, Celtis africana, Euclea natalensis, F. albida, Hyphaene coriacea, Salix fragilis and Trema orientalis. The exotic species used in environmental protection include Acacia dealbata C. cunninghamiana and Populus canescens. Some of the species like P. canescens are now known to be highly invasive in other countries such as South Africa and Zimbabwe were the species chokes waterways.