2. WOODFUEL PRODUCTION

From around the late 1980s, there have been no defined forest management prescriptions that are practically being implemented for woodfuel production. On paper, however, a number of management prescriptions have been suggested that are envisaged to increase productivity of both forests and woodlands in provision of products and services on a sustainable basis.

To have a comprehensive understanding of woodfuel production, this paper will define production systems to mean forest ecosystem types and their management for the production of biomass and/or biodiversity for provision of forest products and in this context woodfuel. The definition will go further to imply the various conversion methods used to transform trees into woodfuel and harvesting systems used. This section on production will borrow heavily from studies conducted in the miombo woodlands (which cover between 55% and 60% of total land area) by Professor E. N. Chidumayo and A. Marjokorpi (1996 - 97), M. Grunder (1995), P. L. W. Chitondo (1997) and the Forestry Department (1995 - 1999).

Ecosystem nomenclature in Zambia is based on vegetation types and Chidumayo and Marjokorpi (1997) have identified five forest types (Dry evergreen, Dry deciduous, Montane, Swamp and Riparian), five woodland types (Miombo, Kalahari, Mopane,

Munga and Termitaria) and Grasslands. In addition to the natural vegetation types, plantation forests of tropical pines and eucalyptus covering about 61,000 ha. have been established countrywide, with over 80% of these occurring on the Copperbelt Province. About 50,000 ha. of industrial plantations are found on the Copperbelt of which about 80% are pine and 20% eucalyptus. These are currently managed by a parastatal company, ZAFFICO Ltd. About 7,000 ha. of Local and Regional supply plantations in the Provinces are managed by the Forestry Department. The rest are plantations and woodlots managed by individuals at the semi-commercial and farm levels.

Dry evergreen forests occur in the high rainfall zone with over 1100mm, on deep freely draining soils with adequate underground water. The dominant genera are Marquesia, Parinari and Cryptosepalum.

Dry deciduous is a low rainfall (600 - 900mm) vegetation type on deep and usually sand soils which remain moist at depth during a greater part of the dry season. Dominant genera are Baikiaea and Guibourtia. The forest type covers parts of Western and Southern Provinces.

Swamp and Riparian forests occur in the high rainfall zones of North-Western, Luapula and Northern Provinces and parts of the Copperbelt Province. Swamp forests are characterised by dominant trees, which have buttresses and stilt roots to give stability on damp ground. Swamp and Riparian forests are also common at stream heads, streamsides, river estuaries and on wide flats besides rivers and lakes. Dominant genera are Ilex, Mitragyna and Syzygium.

Miombo woodland is the most extensive vegetation type in Zambia and is estimated to cover about 55% of the total land area and is dominated by tree species of Brachystegia, Julbernardia and Isoberlinia, which are very good woodfuel species. Soils are generally poor, shallow and slightly acidic, having quartz rubble or laterite underneath.

Kalahari woodland is a variant of miombo woodland that grows on Kalahari sand and is widespread on the sands of Western Province and of the western half of North-Western Province.

Mopane woodland occurs on alkaline soils of Central and parts of Lusaka Provinces. It is also found mixed with Miombo at the bottom of escarpments and with Munga woodland at dambo edges. The dominant and characteristic species is Colophospermum mopane.

Munga woodland is a park-like woodland with trees scattered or in groups. The dominant species are Acacia, Combretum and Terminalia and this vegetation type covers the greater part of Central and Southern Zambia. One prominent characteristic feature is presence of dense tall grass, flat ground and rich clayey soils.

Lake basin Chipya is a vegetation type that probably resulted from the destruction, usually by fire, of Parinari and Marquesia forests. It is three-storied with an open, evergreen or deciduous top canopy up to 25m, a broken understorey 6-12m and a 2-3m shrub layer. It occurs over an extensive area of Northern and Luapula Provinces around Lakes Bangweulu and Mweru and in the Chambeshi and Luapula valleys. The soils are pale, sandy and very acidic. It also occurs on the Copperbelt where it is called Copperbelt Chipya.

Kalahari sand Chipya is assumed to have been derived from Dry Evergreen forests that were destroyed by fire. It is open and composed of fire hardy species.

Anthill (Termitaria woodland) is a Savannah vegetation that is dominant in the transition between wetlands, grasslands and plateau forest or woodland. It has tree groves or termite mounds and grasslands on low ground. This woodland supports a community of plants, which is usually very different from surrounding forest or woodland. This is due to such factors as raised elevation, higher clay and mineral content of the soil, high pH, higher moisture content of the soil and a greater biological activity. Species of Boscia, Strychnos, Diospyros and Sterculia are common.

Grasslands are either edaphic or secondary and cover dambos, flood plains and margins of pans, swamps and lakes. They are found also in all land that is naturally without trees and in places with a permanently high water table. The dominant grasses belong to the genera Acroceras, Leersia, Oryza, Panicum, Paspalum, Sacciolepsis and Vossia.

Open areas outside conservation areas (i.e. Forest Reserves, National Parks and Game Management Areas) contain the highest proportion of each vegetation type. In fact, Swamp and Riparian forests are not represented in conservation areas. Plantation forests and Miombo woodlands are well represented in Forest Reserves as are Deciduous forests, Miombo, Kalahari and Termitaria in National Parks, while Kalahari, Mopane, Munga and Termitaria woodlands are well represented in Game Management Areas.

The Total area under forest cover in Zambia is estimated to be 44.6 million hectares, out of which Savannah woodlands account for about 71% of the total land area. Savannah woodlands are dominated by the Miombo, which covers between 41.2% and 55% of the country’s total area (Forestry Department, 1999).

In relative terms, the Forestry Department (1999) estimates the vegetation cover to be distributed as follows:

-Savannah woodlands - 65.49%

-Closed forests - 5.37%

-Grasslands - 29.04%

Within climatic limitations, composition and character of vegetation is governed by soil and drainage conditions which in turn are related to geomorphology (Chidumayo, 1997).

Both biotic and edaphic factors affect the dynamics of vegetation. The majority of indigenous trees and shrubs have a high potential to regenerate from seed, stumps and roots. However, regeneration can be adversely affected by over-browsing and uncontrolled late forest fires. Repeated browsing results in preferred species being depleted, while frequent late dry season fires eliminate fire tender species, thereby preventing adequate forest regeneration. Consequently, use of fire in shifting cultivation has resulted in widespread destruction of original tree cover in Zambia and its replacement by secondary vegetation.

The fact that Miombo woodlands regenerate unchanged after clearing, Chidumayo and Marjokorpi (1997) considered that Miombo woodland is mostly regrowth of variable ages as a result of fire, cultivation and exploitation. In contrast, Chipya forest, in which fire-tolerant species dominate over a tall herbaceous layer, represents a regressive stage after destruction of Dry Evergreen forest. Apparently, reversion to Dry evergreen forest is possible with protection from fire.

Of the total land area in Zambia, about 9.9% are gazetted Forest Reserves. Out of this Forest Estate area, 44% is set aside for Production, 30% for both production and protection, while the remaining 26% is specifically for protection (ZFAP, 1997).

Table 2.1 : Size of Forest Estate and Purpose of setting aside

Source: ZFAP, 1997

It is, however, unfortunate that no comprehensive forest inventories have been conducted in the last three decades. The 1984 - 86 Survey was only undertaken in a few locations and existing yield estimates are essentially based on assumptions of changes that have taken place during the last 30 years. This Survey estimated growing stock to vary from 40 to 154 m³/ha. by Province (ZFAP, 1997).

Table 2.2: Estimation of standing stock in 1996; FR = Forest Reserve FOA = Forests in open areas

Source: ZFAP, 1997

Note: Stocking of TOF = 5m³/ha, plantations are included in FR.

The above table gives the estimated standing stock in solid cordwood volume, in about 4,900 million m³. This figure could be converted to biomass using the above-mentioned estimate, resulting in a total of about 3,700 million tonnes.

Latest information compiled by the Forestry Department after the ZFAP and PFAP processes (1995 - 98) is as reflected in the table below:

Table 2.3: Growing stock and increment rate according to forest type.

Source: Forestry Department, 1999

The rate of growth of natural forests is rather low, ranging from 0.7m³ to 2m³/ha/annum. Hence, the indicative aggregate biomass volume of all forest types is about 3,700 million tonnes (Forestry Department, 1999).

Chidumayo (1997) has stated that plant productivity in the Miombo woodland primarily depends on:

1. Soil moisture; and

2. Soil available nutrients

Rainfall is seasonal and availability of soil nutrients is low. Consequently, productivity is low.

Grunder (1995) suggests that vegetation cover intercepts rain drops and reduces its dislodging capacity to the soil. He also notes that vegetation cover increases, through litter fall, the organic matter content of the soil, which plays an important role in making nutrients available and in particular, increases the soil water retention capacity. These factors support plant production and clearly show that good management of vegetation cover is important for the sustainable and increased production of woody and agricultural products.

Forests with closed canopy (and therefore optimal protection) are limited in extent in Zambia and cover only 6.5% of the total land area. Woodlands, with a reduced cover on the other hand, account for about 70% of the total land area (Grunder, 1995).

Chidumayo (1997), recognises two main aspects to Miombo woodland management for increasing plant productivity:

1. Sustainable utilisation of products

2. Sustainable regeneration of products and services

Sustainable Utilisation

Chitondo (1997) has suggested the following measures for the sustainable utilisation of Miombo woodlands:

--Instituting clear felling or coppice harvesting systems as the most appropriate for charcoal production.

Under such an arrangement, forest areas are divided into coupes which are laid out in blocks of five (5), with each block measuring 100m wide and the sixth being 110m wide and left uncut as a protection belt. This gives a beacon every 610m. Protection belts are also left at every end of coupes. Coupes have been found to be most applicable in areas that have been selectively thinned for sawlogs, in which merchantable commercial timber species have been removed. However, the system is at the moment just on paper and is not practised by charcoal burners.

Nkomeshya (1997) has listed the following tree species for firewood production:

*Julbernardia paniculata (Mutondo, B)

*Julbernardia globiflora (Sandwe, B)

*Brachystegia boehmii (Musamba, B)

*Brachystegia spiciformis (Muputu, B)

*Bauhinia thoningii (Musekese, B)

*Pericopsis angolensis (Mubanga, B)

*Parinari curatellifolia (Mupundu, B)

*Uapaca kirkiana (Musuku, B)

B = Bemba Language

The above tree species are preferred because of their high heat content value and that they last long in burning. Based on the same principle of heat value and durability in burning, preferred charcoal tree species are not so different from those used for firewood. Selectivity in woodfuel tree species has resulted in localised scarcities of the preferred species. However, due to continuously increasing demand for woodfuel and depletion of priority species, current-harvesting methods do not segregate on species and this situation has culminated in complete degradation of certain forest areas. Natural regeneration in these areas has become almost impossible (under current institutional arrangements and economic situation) because regrowths are rarely given a chance to develop into mature trees - some are cut immediately they start to show signs of stem rigidity and others are destroyed by late fires which are very common, especially in livestock areas and in areas under the slash and burn (Chitemene) system of agriculture.

Zambian charcoal and firewood are estimated to have heat content values of 32.60 and 15.50GJ/tonne respectively (Department of Energy, 1992). Charcoal is, therefore, the most preferred of the two by most urban markets because of its superior qualities over firewood e.g. cleaner combustion, easy transportation and handling and high heat value. Rural communities on the other hand prefer firewood because they can not compete for charcoal with urban customers whose high demand leads to increased prices which the income ‘stripped’ rural dwellers can not afford. Lack of alternative income generating ventures further alienates rural dwellers from use of charcoal because even those who are able to produce the commodity, would rather offer it for sale to fill the income gap and use firewood for their energy requirements.

The major problem that has been associated with charcoal production, however, is in the way it is produced and the kind of losses incurred in its production. The earth kilns used are mostly 10% efficient, implying that in the process of producing charcoal from wood, 90% by weight is lost. From 100 tonnes of wood, therefore, one only expects to get 10 tonnes of charcoal (Kapiyo, 1996). The charcoal production process should therefore be done in efficient kilns or better still, wood should be burnt directly without first transforming it into charcoal. This will serve to sustain the current available, but highly endangered wood stocks. Promotion of alternative and renewable energy sources should be intensified and implemented.

Sustainable Regeneration

Chidumayo (1997) states that natural regeneration of forests is through seed, stumps (coppices) and roots. He further states that there are five (5) factors that affect natural regeneration:

1. Canopy shading in selective felling systems;

2. Inter-shoot competition, whereby only the dominant shoots contribute to the next generation;

3. Capacity to regenerate (coppice) decreases with age and stem size;

4. Late forest fires which kill seedlings and coppices;

5. Cutting of seed bearers for woodfuel and sawlogs and clearing for agriculture. Seed bearers are usually cut because of their bigger diameters and hence are preferred for timber as sawlogs. This contributes to poor regeneration from seed.

The average establishment period for natural regeneration has been calculated at 8 years for both seedlings and coppices, but this varies between 2 and 11 years depending on species. Normal establishment period for new crop is best regarded at 10 years when stool mortality and different sources of regeneration are taken into account (Chitondo, 1997). The cutting cycle in selective cutting areas is 20 years and 60 years in clear-felled areas. 100 years are regarded as the period needed for a tree in a Miombo woodland, under natural conditions, to attain DBH of 30cm. Silvicultural treatments have proved to reduce this period to 60 years on average quality sites and 50 years on best quality sites (Chitondo, 1997).

Chitondo (1997) has also indicated that stumps of almost all Miombo species have the ability to coppice. Many shoots may be produced on one stump, but this reduces due to inter-shoot competition and therefore, as stated earlier in this paper, only dominant shoots contribute to the next generation. On stumps for valuable species, singling may be applied to leave only one dominant shoot. However, stump trimming is rarely done and hence the rate of stump rot is high and regeneration through stumps is reduced. This problem has also been compounded by inadequate supervision and control by the Forestry Department.

Root or vegetative regeneration is most prevalent in stumped, uprooted and machinery-logged areas. Unless damaged by fire, such regeneration produces straight poles in the medium-term and timber in the long-term. In recent times, such poles have been used for firewood in wood deficit areas. Artificial regeneration has been used to ensure complete regeneration in areas where no seed trees exist or where they are widely scattered.

Chitondo (1997) has identified the following as the main failures in the implementation of natural regeneration:

1. Institutional failures by the Forestry Department to supervise felling;

2. Lack of training for loggers;

3. Death of suckers from late forest fires as a result of lack of early burning;

4. Seed bearing trees are not reserved.

Artificial regeneration is also not practised in natural forests and cutting cycles are not followed due to non-existent of management plans.

Chidumayo (1997), has gone further to suggest that the provision of wood products by the Miombo woodland is limited by:

1. Productivity; and

2. Quality of the wood resource

Wood production is also affected by the response of miombo trees to harvesting. The response depends on:

*Phenological state of trees at the time of harvesting;

*Degree of tolerance to fire;

*Ability to resprout;

*Seeding patterns;

*Seed germination characteristics;

*Seed development; and

*Tree growth rate.

In addition to the above factors, Chidumayo (1997) also states that the rate of regeneration in the miombo woodlands is affected by human activities.

To further enhance the productivity and quality of the wood resource, the following arguments have been proposed:

That since tree regeneration in the miombo is through seed and/or vegetative regrowth and because tree seedlings possess the following characteristics:

*Slow initial growth during root development and growth (up to 15 years);

*Shade induced growth suppression during post root development and growth (indefinite period),

Seeds produced immediately before woodland clearing do not contribute to the succeeding regrowth stand. Seedlings and/or suppressed saplings accumulate in the herb layer over time and consequently predominate the woody plant population in old growth miombo.

The majority of miombo trees will respond to cutting by resprouting and within a stand or species class, resprouting will depend on:

*Vigour of dormant buds and/or the bark thickness which are also related to the age/size of a tree;

*Phenological or health status of a tree at the time of cutting;

*Health status of a stump after cutting.

Because the tree density increases with each succeeding generation of regrowth, the contribution of stump coppice to regeneration increases with each succeeding regrowth miombo.

The tree cutting height has also been found to affect the nature and rate of regeneration and the quality of wood products e.g. pollarding, stumping and uprooting will all lead to regeneration with specific wood qualities. The time of cutting affects wood production, especially during the first year after cutting, depending on the phenological phase in which a tree is at during the time of cutting.

Table 2.4 : Broad phenological calendar of miombo trees

Phase	Period	Resources Used
Leaf flush	Sept. - Oct.	stored resources, especially from roots
Shoot elongation	Sept. - Dec.	stored resources plus photosynthates
Stem expansion	Sept. - March	stored resources plus photosynthates

Source: Chidumayo, 1997

Cutting down trees after stored resources have been used during leaf flush reduces growth during the first growing season and the duration of the growing season is reduced.

Fires also affect the active regeneration of miombo woodlands depending on:

*Size/height of stem;

*Species tolerance to fire;

*Fuel biomass/fire intensity;

*Time of burning - early or late in the dry season;

*Phenological phase at the time of burning (before or after leaf flush);

*Bark thickness;

*Wood moisture content; and

*Capacity to resprout after damage by fire.

Generally, fires that occur in miombo woodlands reduce stem density, productivity and annual biomass increment and the quality of poles. Fierce and damaging fires occur late in the dry season, especially after leaf flush due to high leaf biomass. Tree species that flush early are, therefore, more susceptible to fire damage.

Early burning has consequently been suggested to be less destructive, but in recently cut-over areas, as Chidumayo (1997) states, the amount of wood debris, if not removed, is usually very high and in such instances, even an early burning exercise would be fierce and damaging to young coppices. Under such conditions, complete fire protection may be necessary to promote forest production, but is not practical because of:

1. The high risk of destructive accidental fires due to the building up of fuel biomass

2. Cultural applications of fire by communities inhabiting miombo woodlands

Fire management in miombo woodlands should therefore take into account:

1. The age of the woodland;

2. Size of stems;

3. Phenology of dominant and/or desirable species;

4. Type of land use;

5. Management objectives of an area (especially forest production versus grazing).