Part II
COUNTRY BRIEFS (continued)

SUDAN (continued)

1.1.2 Present situation of the woody vegetation

Present areas

Areas of natural woody vegetation estimated at end 1980
(in thousand ha)

The figures are principally based on the areas per vegetation types elaborated in the late fifties (2) and updated to 1980 as no nationwide reconnaissance has been carried out since. They have been distributed over the categories used in this study, as indicated in the following table:

It must be emphasized that adequate and reliable data are not available at present and the figures in the previous tables are merely rough approximations. To interpret the latter in their correct dimensions, the following clarifications are necessary:

• the bulk of the northern and central parts of the Sudan are covered by desert shrubs with a small amount of forest in moister localities, e.g. along watercourses. The relatively negligible areas of Acacia nilotica stands have been classified as productive managed closed broadleaved forests (NHCf1m = ε);

• the semi-desert vegetation belt has solely scrub (60%), grassland vegetation (around 40%) with grazing potential and Acacia nilotica forest under working plan (NHCf1m); 60% of the total area covered by this species have been classified as closed forest intensively managed (NHCf1m), the remaining 40% are considered as plantations since it is assumed that they have been established on land which previously did not carry this type of stand (see also section 1.2.2);

• because of their vegetation, Acacia mellifera thornland, Acacia senegal savanna and Combretum cordofanum - Dalbergia - Albizia sericocephala savanna woodland are considered as scrub (nH);

• it is understood that in many cases the area indicated for this scrub covers also areas influenced by agriculture such as grazing (semi-desert), irrigated crops (flood region) etc.;

• shifting cultivation is practised to a variable extent in the woodland savanna and is estimated to occupy 15% of the respective areas, including areas under woody vegetation used for cattle grazing and breeding;

• the areas mentioned in (5) as productive forests in the woodland savanna, with exclusion of all scrub types, have been classified as productive “open broadleaved forests” (NHc/NHO1);

• the hills and catenas in the low rainfall savanna woodland bear little productive woody vegetation (10%) but the area of poor grassland mixed with thickets of trees is extensive (50%);

• due to climatic conditions, scrub (nH) is only sporadic in high rainfall woodland savanna, and unproductive woodlands (NHc/NHO2i) are less frequent because the forest vegetation is generally more developed;

• relics of tropical rain forests and gallery forests have been estimated to occupy 5% of the area under derived woodland and 15% of the latter should be considered as fallow forest;

• roughly 5% of the surface under flood regime - the parts situated on the higher lands - are assumed to be “productive” woodlands (NHc/NHO1). A subdivision of the remaining local vegetation has not been made because of lack of information. Therefore it has been classified as a pastoral area (5) with scrub vegetation (nH);

• existing forestry legislation never prohibits logging of closed forests (NHCf2r = 0), but consists of a set of controlling measures;

• the montane vegetation of the Jebel Marra range is restricted to scrub and patches of woodlands with human interference (18);

• the present total area of natural forests where conifers are predominant (Podocarpus milanjianus) or appear in pure stands (Juniperus procera) is estimated at 10 000 ha about half of it being productive (3);

• approximately 1 600 000 ha of unproductive woodlands are assumed to be included in the three national parks (NHc/NHO2r);

• according to existing maps, steep slopes above 1 800 m altitude cover some of the Imatong Central Forest Reserve. Of the remaining part (60%) on the lower slopes of the high plateau, about half is degraded secondary forest, owing to uncontrolled cutting, fire and shifting cultivation. Hence, it has been assumed that the vegetation of the montane zone, about 20% already taken up by Jebel Marra, consists of 50% of inaccessible forests on steep slopes (NHCf2i), of 20% of productive closed forest (N.f1) and for the rest of forest fallow (N.a) (17).

The area occupied by 'forest' vegetation not influenced by agriculture and with exclusion of the scrub type totals 47 750 000 ha (NHCf + NHc/NHO). Most of it is located in the southern region particularly in the Equatoria, Bahr el Ghazal and El Bucheyrat provinces. The area of scrub vegetation (nH) is very approximative and includes some agricultural and grazing lands.

Ownership

The whole present forest estate belongs to the state. It is regularly increasing through forest reservation. Certain forest reserves, however, are or will be incorporated within the Rahad Agricultural Projects and thus fall under the authority of the respective projects. There are also some forest reserves which belong to government corporations, such as the Gezira Board and the Khashm El Girba Scheme. Private and cooperative forest reserves do not exist at the moment (22).

Legal status and management

Natural forests are protected by the Forest Law edicted in 1932 and the provincial local forest standing orders issued within the terms and framework of the Law (22). The forest reserves are generally those areas where the cutting of trees is concentrated and replanting made immediately after felling (1). The fully constituted and gazetted forest reserves covered 1 280 000 ha at mid 1977 (0.51% of the total country area) distributed as follows among the vegetation zones: 1 690 000 ha in the semi-desert, 547 000 ha in the low rainfall woodland savanna and 564 000 ha in the high rainfall woodland savanna. The forest reserves surveyed, mapped but not yet gazetted totalled 554 000 ha at the same date (25). Decrease in reserved forest area by way of alienation to farming during the period up to 1980 was expected to be nil. On the other hand, an appreciable increase was expected during the same period. The 6-year development plan for forestry (1977–83) has set as an annual target an area of 210 000 ha to come under forest reserves for purposes of land protection, watershed management, farm forests, forest utilization and timber growing, playing the dual role of being protective as well as productive (22). Forestry legislation also controls tree cutting outside forest reserves directly and indirectly through leveying of royalties, with the major objective to concentrate felling inside forest reserves.

There are 3 national parks covering a total area of 2 350 000 ha: Dinder national park (640 000 ha), Southern national park (1 685 000 ha), Nimule national park (26 000 ha) (25). A fourth one, Radom national park, covering a total area of 1 250 000 ha is under establishment (25). The present Wild Animals Ordinance, established in 1935, protects animals by prohibiting illegal methods of hunting in the area and also provides details of hunting licences and fees. Game reserves total 3 537 000 ha (14).

The area of natural forest presently under intensive management is relatively small and belongs partly of the Northern Fung Working plan, which encompasses a total area of about 50 000 ha. The silvicultural system prescribed is that of clearfelling followed by regeneration by sowing (22). The total area under working plans, including man-made forests, is 78 119 ha of forest reserve estate and is composed of the Northern Fung Forest Circle, the irrigated forests at Qoz en Naga, the irrigated forests of Fawar and Turis, Khartoum Sunt Acacia nilotica forest, the Rahad Sunt Acacia nilotica forests, the middle part of the Khartoum Green Belt irrigated plantations, the Sunt Acacia nilotica riverain forest reserves of the Gezira Forest Circle and the Tewfikia forest in the Upper Nile province (25).

Forest utilization

Log harvesting

Logging for the production of industrial timber is done under the supervision of sawmill and industry managers who are directly responsible to the assistant commissioner of forestry within their respective provinces. The logging operations are usually done by contractors. The main exception is that of the two match factories in the northern part which are using the species Sclerocarya birrea. They usually handle the felling and transportation of logs themselves and pay royalties according to the size of the logs to the forest authorities of the province concerned (16).

The axe is still the main tool used for felling, while powered chainsaws are being introduced. Felling saws are used for the necessary back cuts. Extraction and loading of the logs is partially manual. The Forest Department generally supplies felling and extraction equipment. Losses due to these two operations do not exceed 5%. Royalties are agreed upon by contract on the basis of volume felled. Private enterprises have the greater share in loading, transport and unloading but loss occurred is great and exceeds 20%. This is mainly due to the inadequacy of loading and transporting methods for the big, heavy and badly cut logs which are often left behind in the forest (22).

Industrial logs are then transformed in one of the 17 circular sawmills owned by the state or in one of the 3 privately owned sawmills (24). Waste is important and exceeds 70% in most sawmills. Considering an estimated production of 15 000 m³ annually in government sawmills and 700 m³ in privately owned sawmills and taking into account 25% losses during felling, extraction and transport and 70% waste in sawmilling, an annual production of about 70 000 m³ of sawlogs originating from natural forests can be assumed (22). The match factories are reported to require 3 500 m³ of solid wood per year (5), corresponding roughly to 5 000 m³ of logs (logging losses being estimated slightly higher). The total annual output of the natural forests can thus be estimated at 75 000 m³. The bent-wood chairs factory in Khartoum and the particle-board factory are known to be supplied with wood from plantations (Balanites aegyptiaca, Eucalyptus spp.) (23) and some Boswellia papyrifera (7).

The forest areas suitable for industrial timber production are almost entirely confined to the southern region and to limited areas along the riverbeds in the rest of the country. The desert, semi-desert and flood regions do not have importance in this respect, while the low rainfall woodland savanna is producing mainly fuelwood and building poles for housing (7).

In the systematically exploited stands of Acacia nilotica, the average yield of the final cut is about 55 m³ per ha of which about 4 m³ are suitable for sawnwood production.

Nine major species are utilized for sawn timber: Isoberlina doka, Khaya grandifoliola, Acacia nilotica, Olea hochstetteri, Podocarpus milanjianus, Chlorophora excelsa, Afzelia africana, Daniellia oliveri and Khaya senegalensis. Boswellia papyrifera has been used for the manufacture of particle board and for match boxes (7).

Other forest products

Other roundwood

Sudan timber is used extensively in the form of poles and posts. Apart from village housing which is made of saplings and poles of species resistant to decay and insects, the towns use large quantities of building and telecommunication poles. Quantities of round timber and bamboo (Oxytenanthera abyssinica) are needed locally by citizens in rural areas. The per capita roundwood consumption of the country can be estimated at 0.085 m³ (5), which amounts to a total for 1980 of about 1.7 million m³. Official statistics mention a departmental registered production of 1 million pieces a year (19), including plantation products. Figures on rural production/consumption are not available. Other local uses for industrial roundwood include artisanal production of boats, bowls, saddles, carts, oil presses, water wheels and a host of others. The timber quantity used annually for these uses are unknown and difficult to estimate (1).

Fuelwood and charcoal

The fuel used by most of the inhabitants, except a few in the main cities, is confined to wood and charcoal. (23) mentions a registered production of 260 000 m³ of firewood and 188 000 tons of charcoal for the fiscal year 1974/75. The actual figures for commercial production of firewood and charcoal, however, are expected to be much higher than the quoted ones, which are figures derived from royalties collected on these two commodities. With a per capita consumption of about 1.9 m³ (5), the estimated total fuelwood requirement in 1980 is 40 million m³ although the 1978 FAO Yearbook of Forest Products indicates a total production of 27.5 million m³ only. Logging for charcoal production is done by private enterprise usually directed to areas set for agricultural clearing but in many cases also to zones inside forest reserves to be transformed in plantations.

Minor forest products

Gum arabic is the most important minor forest produce. The annual crop exported is about 45 000 tons (19) (24). Kordofan Province in the western Sudan is the main production centre. The grey barked Acacia senegal produces hashab gum and the usually red barked Acacia seyal talh gum. The latter is inferior in quality. Most gum gardens are still natural (1). The dom nut, an important vegetable ivory is obtained from the palm Hyphaena thebaica. The dom nuts are sliced and exported as button blanks for making buttons. An average of 1 500 tons is exported annually (1) (19). Other minor products are bee honey and bees wax, the latter being exported at a rate of 80 tons per year, palm oil (Elaeis guineensis), garad tanning pods obtained from Acacia nilotica, lulu oil from the Butyrospermum nilcticum and chillies, fruits of a shrub species Capsicum frutescens (1).

1.1.3 Present situation of the growing stock

Present information and statistics on the forest resources of the Sudan are very scanty and cover only a small part of the whole country. The few available statistics on volumes are admittedly not based on adequate methods of sampling and therefore the quoted figures are mere estimates. Where data, specific for the Sudan, have not been found (for NHCf1uc and NHCf2), the estimates on growing stock per ha made for Kenya, country on the south-eastern border with similar ecological conditions and vegetation cover, have been applied.

Growing stock estimated at end 1980
(totals in million m³)

Areas of vegetation types used to calculate total volumes over bark are those mentioned under 1.1.2. The intensively managed Acacia nilotica forests are managed on a rotation of 35 years, corresponding to an annual allowable cut of 1.6 m³/ha. (3) quotes a yield of 53.8 m³/ha in some areas without irrigation. Therefore, a medium standing stock of 55 m³/ha seems plausible for all such stands. The commercial volume (VAC) in the productive woodlands is estimated at 3 m³/ha, mostly Isoberlinia. The growing stock of Podocarpus milanjianus in the coniferous productive forests has been evaluated at 160 000 m³ in total (3). In addition, the Juniperus stands of the Red Sea Hills represent also, to a lesser extent, an industrial potential. The growing stock per ha has been estimated at 90 m³ for the productive parts and at 60 m³ for the inaccessible (because of their rough mountainous character) zones.

Increment

(12) gives an estimate of the potential annual yield of sawn timber for Sudan (1960) based on fragmentary information.

These annual yield figures are probably overestimates under the present prevailing conditions. Over-mature trees represent the main bulk of the southernmost forestry belt and gallery forests, with few younger trees, poles and saplings of commercial species as regeneration. Moreover, there has been a decrease or degradation of the forests and woodlands. Foothill galleries and montane forests have very low potential and the main volume of the available wood potential is made up of Isoberlina spp. If the figures for southern region production in the seventies are correct, there must have been an over-exploitation of the Acacia forests of the north for the production of sleepers. It should also be noted that most of the potential production is suitable as sleepers, but not so much for other types of sawn wood (12)(20).

1.2 Plantations

1.2.1 Introduction

A plantation programme was started in the early thirties throughout the country, mostly with teak as well as other hardwood species for production of sawlogs, fuelwood and poles. Softwood plantations did not start until the forties on the Imatong mountains around Gilo. Afforestation is now carried out in all parts of the country mainly in the southern, western and central Sudan. Small-scale irrigated plantations have been established in the northern part of the country. Plantation for protection in the form of shelterbelts, against desert encroachment in the vicinity of fertile agricultural lands, are established in the most susceptible areas of the different provinces. All plantations are publicly owned, although some are located outside forest reserves. However, 60% of the Acacia senegal plantations established after 1977 should be in private holdings according to the present “6-year plan of economic and social development” (1977/78–1982/83). Free seed and technical advice are provided by the Forestry Department to interested farmers (21). About 50 000 ha of plantations in the woodland areas have been established under the “taungya” system, as indicated in the FAO publication “Savanna afforestation in Africa” (1977).

1.2.2 Areas of established plantations

Plantations should cover at the end of 1980 slightly over 185 000 ha. Detailed statistics up to 1969 are provided by (10), from 1970 to 1973 by (23), and after 1973 by (21) and (25).

Industrial plantations

Areas of established industrial plantations estimated at end 1980
(in thousand ha)

¹ Areas planted by species were available only from 1948 onwards.

It has been assumed that the annual planting rate for the period 1978–80 equals the one of the two previous years.

“Mixed plantations” include indigenous as well as exotic species. The term ‘others’ covers the following species, each of them with a total area of less than 500 ha: Afzelia africana, Albizia alymeri, Balanites aegyptiaca, Boswellia papyrifera, Bombax malabaricum, Ceiba pentandra, Chlorophora excelsa, Daniellia oliveri and Maesopsis eminii as broadleaved species (PHL1), Pinus spp. and Podocarpus spp. as coniferous species (PS.1).

Of the estimated total area of man-made forest established before 1948 (4 200 ha), one quarter is assumed to be for industrial purposes. Although the stands of Acacia nilotica are merely important for the production of firewood, they are also a source of sawn timber, especially sleepers, for the northern Sudan. They have therefore been classified as industrial plantations.

The particle-board factory is supplied by wood from the “green belt” which has been established south of Khartoum and is irrigated by its sewage effluent. Eucalyptus camaldulensis is used by the factory and is felled and transported by the factory authorities under the supervision of the Forestry Department. However, all eucalypt plantations have been classified as “non-industrial” (PHL2), because of the relatively small amount of wood used by this mill compared to the production of poles and fuelwood (11).

The total area indicated for Acacia nilotica corresponds to the stands of this species which have been established on land not carrying the same type of forest before. They cover approximately 40% of the total area of Acacia nilotica stands.

Other plantations

Areas of established non-industrial plantations estimated at end 1980
(in thousand ha)

Acacia senegal is chiefly grown for the production of gum arabic but its wood serves also for charcoal production and as firewood, such as the other Acacia, Cassia siamea and Hyphaene thebaica. Azadirachta indica is mainly planted as shade tree and Prosopis chilensis proved to be excellent in the establishment of shelterbelts. ‘Others’ include the following species: Ailanthus excelsa, Callitris spp., Conocarpus lancifolius, Dalbergia sissoo, Gmelina arborea, Tamarix spp. and the bamboos Bambusa vulgaris, Dendrocalamus strictus, and Oxytenanthera abyssinica.

The indicated totals per age class are the sum of the annually planted areas as shown in the annual reports of the forest administration. They include failed plantations and partially destroyed stands. It is worth nothing also that recent annual plantings are estimated by pacing and in most cases also by the number of plants provided by the nurseries. Most tending programmes have been discontinued over the last 15 years (20). For all these reasons present plantation data do not reflect exactly the situation.

All plantations

A global overview of the actual situation of the man-made forests is represented in the following table:

Areas of established plantations at end 1980
(in thousand ha)

1.2.3 Plantation characteristics

The following table summarizes the main stand characteristics. More detailed information per species is given underneath.

Plantation characteristics

* in “Savanna Afforestation in Africa” (Document FAO/FOR TF-RAF 95 (DEN))

Acacia nilotica

The establishment techniques described below apply mainly to the Acacia nilotica plantations along the river banks in the north of the country in the seasonally inundated areas, the most important ones being situated along the Blue Nile south of Sennar and along the Rahad and Dinder rivers. The proposed plantation site is cleared of all felled slack and burned off just before the rains commence. As the river flood recedes, seed is either broadcasted or dubbled in at specified intervals in pits, the latter system being used to a quarter extent nowadays (6). A fully stocked pit sown crop starts with 2 500 stems per ha, broadcast crops usually have a higher density. A preliminary brashing to remove all wolf and badly formed trees is carried out during the fifth or sixth year and the crop is reduced to 1 200–1 400 stems per ha. The second thinning is carried out three years later, taking about 50% by number of stems. The suppressed and subdominant trees are removed. The third thinning is executed when the stand is 12 years old, taking out another 30%. The fourth and fifth thinnings are carried out at the ages of 15 and 18 years when growth is at its maximum. Each time 20% by number of stems is taken out reducing these to 330 and 260 individuals per ha respectively. All suppressed, subdominants and some co-dominants are removed. Further thinnings (21st, 24th and 27th year) gradually reduce the crop to about 120 to 190 stems, depending on the site quality class. The rotation is determined in order to produce a large proportion of logs suitable for railway sleepers (25).

Eucalyptus microtheca

This species is raised in irrigated plantations with the purpose of producing firewood and building poles. When grown as coppice, one thinning reduces the number of shoots per stump to 3 or 4.

Tectona grandis

The first plantations were carried out in 1919. Since then, teak has become the most important species planted for the production of sawnwood. However, the species is said to have been used often on unsuitable sites and under improper plantation techniques (3). Mean annual increments in diameter of observed teak plantations in Bahr el Gazal Province (stands of 20, 30 and 48 years of age) amount to 0.6 cm or less, and only a few isolated roadside trees of some thinned stands show an annual increment of 0.8 cm (20).

Softwood plantations

Many of the older stands of cypress and pines (Pinus patula, P. radiata) have never been thinned. The thinning scheme as indicated in the previous table for cypress could be applied when possible (18). There are very few small areas of other conifers which are considered as research planting (18).

2. Present trends

2.1 Natural woody vegetation

2.1.1 Deforestation

Traditional shifting cultivation is the main source of deforestation in the dense forests of the Sudan, situated mostly in the southern part. The following rough estimates represent the annual deforestation rates

Average annual deforestation
(in thousand ha)

Periods

Almost everywhere, there is some shifting cultivation going on, although the forest authorities in the different provinces apply rigorous local forest standing orders to limit and organize this activity, which generally occurs in small patches close to settlements. Because of these controlling measures, deforestation rates are estimated to be 20% lower between 1981 and 1985. Deforestation takes place mostly in the unmanaged productive closed forests (NHCf1u) of the southern zone and to a very small extent in the predominantly coniferous forests (NSf1) and in the montane region (NHCf2i).

The total area of savanna woodlands is continuously decreasing due to expansion of irrigated agriculture or rainfed mechanized crop production zones, to fires, traditional shifting cultivation and increasing removals of fuelwood. An annual loss of 20 million cubic metres is estimated (20).

One of the most significant developments of the last 15 years has been the continued expansion of mechanized crop production schemes with large-scale tree clearance operations in the eastern part of the Sudan. This has largely reduced the area of unreserved savanna woodlands in this zone and equally local supplies of wood for charcoal. However, in some cases (16) areas of old mechanized crop production schemes are handed over to the Forest Department and put forthwith under regeneration by mechanical sowing of Acacia senegal in particular. In the savanna woodland of central Sudan, the rural population is largely semi-nomadic and pastoral. Shifting cultivation is practised mainly on small patches for production of crops such as dura and sesame, or on large patches cultivated under the traditional ‘harig’ system. This consists of burning of the mat of dead grass, the result of several years growth, after the first showers of the rainy season, to fertilise the soil and to provide a clean seed bed for the agricultural crop of that rainy season (11).

A controlled form of shifting cultivation is practised in the gum arabic producing zones in the west of the country. At any one time, only a small portion of the holding, be it individual or tribal, is under an agricultural crop, the remaining part being under fallow, with Acacia senegal trees for the production of gum arabic and grass. Thus, the cultivation shifts around within the holding on a long rotation of some 25 years (8).

In the Blue Nile Province, the control of rainfed shifting cultivation consists in technical supervision for the clearing operation in order to leave mother trees to reseed the area after its abandonment (23).

2.1.2 Degradation

Reasons for deterioration of tree cover in the White Nile Province include intensive grazing, frequent fires, illicit tree cutting, expanded rainfed and irrigated agricultural schemes, shifting cultivation and inadequate rainfall in some years. In the Darfur and Kordofan Provinces, the migration of drought-stricken communities from north to south, resulting in an increased pressure on land for rainfed cultivation, and fires are the two main factors leading to the degradation of the vegetation cover. Sand encroachment aggravates the situation in the northern region (23).

2.1.3 Trends in forest utilization

The “six-year plan of economic and social development 1977/78 – 1982/83” foresees an increase of the production of sawn timber from 14 200 m³ to 32 200 m³ through the establishment of new sawmills and the improvement of the existing ones, a target which may be difficult to reach under the actual constraints of the national economy, in particular fuel shortage. Modernization of logging and transport systems is going on. Power saws are being used increasingly for felling, especially in the Acacia nilotica forests of the Blue Nile Province. The work capacity and output rates of Government sawmills are expected to increase gradually. However, production will remain relatively low mainly for fuel shortage in the southern provinces. Timber resources are also getting less accessible and less abundant in the north.

Other targets of the six-year plan are an increase of the annual production of gum arabic to about 60 000 tons by 1983, a doubling of Forestry Department production of roundwood and firewood and a considerable expansion of the public charcoal industry (21). The per capita fuelwood consumption for 1985 is estimated at 2 m³ requiring a production of about 50 million m³, while a per capita consumption of 0.1 m³ of industrial roundwood would result in a total production of 2.5 million m³ (24).