Introduction
Identification of Needs and Possibilities
Production and Management Systems
Selection of Sites, Species and Techniques
This part of the study attempts to bring together factors which are likely to be relevant to project specification. Many of the procedures involved in working out technical solutions are not peculiar to community forestry (site classification, socio-economic survey, etc.), and where these are adequately covered by standard manuals they are omitted or merely alluded to. Similarly there is little or no treatment of types of forest production that are already undertaken on a large scale by forest services (production of sawlogs, pulpwood, etc.). Nor has any attempt been made to prescribe special methods for the management of communally owned woodland, though this form of ownership may account for many millions of hectares which are in need of such attention.
Project Area Survey
Land-Use Planning
Estimating Local Needs for Wood and Fuel
Identifying Other Forest Products
Distribution and Marketing
Environmental Aspects of Forestry
The forestry problems of a community can seldom be solved in isolation. The purpose of a project area survey is to ascertain the needs, problems and possibilities of the community and to determine what priorities the community attaches to them. In many instances it will only be when priority problems have been solved that it will be possible to mobilize community support for forestry.
The formulation of a project should therefore be based on the available knowledge of all the interrelated parameters - physical, biological and human - and should take into account the needs, etc., and the priorities of the community. The investigation should cover the current situation and the various future options and possible trends arising from changes in land use, changes in the intensity of the use of the resources, the application of inputs for increased productivity, and the changing conditions and attitudes such as the purchasing capacity of the community, market conditions, etc.
Because there are many project survey manuals, no attempt is made here to provide an exhaustive check-list that may be applicable for all types of project situations. However, Appendix 1 includes guidelines on the most relevant topics to be considered in a project area survey. In practice, the availability of reliable and adequate information is usually a limiting factor, and time, funds, qualified personnel, rapidly changing conditions, etc., may impose constraints on data collection. However, this should not prevent project formulation; the latter should proceed making use of such information as can be obtained with the resources available.
It is desirable to consider small communities involving several hundred families, living in a physically very clearly defined area such as a watershed, a forest reserve, an irrigation district or a small administrative unit comprising a village or a group of villages. This territorial unit (taking into account spatial interrelationships, e.g., migration, marketing) should constitute the study area in which an inventory of all resources, physical and socio-economic, should be conducted as a basis for sound economic planning.
The depth of the investigation will vary in accordance with the records already available on the environment, its resources and their potential for production, and on the community. The information can be divided into three main groups:
a) the physical and biological environment (climate, soils, vegetation, land use, etc.) and the environmental impacts of current and future human activities, leading to a land capability classification;b) any existing forest and forest-related resources, use of and needs for forest products and the market prospects for forest products;
c) the community, both qualitative (special systems, land tenure, etc.) and quantitative (demography, areas, production, etc.), including survey data from a large sample at farm and family level.
The procedure to be adopted in conducting the survey in most cases will differ little from standard patterns. It is necessary, however, to lay great stress on the need for information to be collected, as much as possible, through members of the community. The aim is to complement the technical, ‘objective’ view of the situation with a picture of it as it is perceived by the inhabitants. The process of collecting information and opinion will also be the beginning of the building of relationships of mutual trust and respect between project sponsors and local people. As far as possible the survey should be carried out by those who are to assist or supervise work, so that enduring personal links may be formed.
For most items in the survey reference should be made to standard handbooks. Three topics which relate specifically to forestry at the community level are treated in detail below: land-use planning, assessment of local needs for wood and fuel, and assessment of existing or potential local or market demand for other forest products and services.
If land is to be used efficiently on a permanent basis, the distribution of uses must correspond with:
- its inherent capabilities, as determined through the appraisal of soil, topography and climate;
- its possibilities of improvement, through restoration, conservation, irrigation, etc.;
- other factors influencing the land-use pattern such as population pressure on land resources, population relocation, land tenure, watershed protection, road infrastructure, distance to market, etc.
The first step in land-use planning is the zoning of the project area into homogeneous physical units. There are several types of land capability classification methods, ranging from quite subjective empirical classifications based essentially on the current land use, to socio-economic classifications which consider dynamic factors in addition to the physical parameters. Simple classifications based on those factors which have a major influence on plant productivity are the most appropriate. The main factors to consider in this approach would be the physical and chemical nature of soil and the limitations, hazards and attributes of the various topographical features. Climate is likely to be important only if the range of altitudes is great, and may be treated as a function of topography.
One difficulty in this approach is the arbitrary rating of parameters. Classifications 1/ based on the land systems approach, which identify land forms and land patterns, considering the recurring characteristics of climate, geology, vegetation, soils, land use and topography as a whole, are a way to avoid this arbitrary rating. Another way is the examination of the land, through a screening process, considering the presence of limiting physical factors.
1/ References on the most common classification systems are provided in Appendix 6.
Potential land-use classes should be restricted in number, and should be recorded on a map indicating the series of uses, ranging from highly suitable to highly unsuitable. In practice the local inhabitants are unlikely to conform exactly to such a scheme, the classification map serving rather as a permanent basis for a negotiating process in which the limits of compromise are represented by the unsuitable uses indicated for each site class. The technical ideal would be to organize production in such a way as to obtain from each site class the most valuable product, without destroying or depleting the soil resources and without creating other environmental hazards in the area of influence (silting, floods, droughts, destruction of wildlife, etc.). Once the land-use pattern with its basic technical and sociological considerations has been agreed upon, it should be adhered to and not be altered at the whims of politicians or other people with local influence.
In land-use planning, particular attention should be given to areas which are currently considered as land still available for cultivation, since on further examination, their quality may indicate that they are not arable lands. On the other hand, lands which may be considered as non-arable, might be made productive for agriculture with a higher level of technology. Conversely, low labour costs and shortage of land make it possible, on certain sites, to terrace steep slopes which would be marginal in mechanized farming. The definition of arable land must take into account inherent fertility, responsiveness to management, the availability of the required technical and financial inputs, the possibility and the responsiveness of the community to adopt improved techniques, and the hazards which may result (e.g., structural deterioration of the soil or pollution of inland waters because of unbalanced application of fertilizers).
Distance to the nearest village and accessibility will be essential factors in deciding between various suitable uses and different intensities of cultivation and management. The areas in which forestry is the preferred use among suitable alternatives will often be those which are unworkable for agriculture, such as steep slopes, or areas remote from settlements. Nevertheless, trees may be planted on arable land if the value of the tree crop exceeds that of alternative crops and if the waiting period can be financed. Tree planting may also be envisaged for agricultural lands along roads, railroads, canals, boundaries, rivers and on the ridges of irrigated plots. The establishment of shelterbelts, the fixation of sand dunes and the protection of the quality of water resources should also be ensured whenever required.
An important component of the process of identification and design of projects intended to provide forest products required by the community must be assessment of the likely order of magnitude of the local need for these products. The starting point for such an assessment will be measurement or estimation of the quantities used at present. But it should also take into consideration how usage might change, or could be changed, in the future.
Fuelwood
The identification of fuelwood needs is likely to require information about four factors:
- the quantities of fuelwood, and other fuels, being used at present;
- the scope for using wood fuel more efficiently, and so reducing fuel requirements;
- the possible need to increase fuelwood usage, e.g., to improve availability of cooked food;
- the availability of fuelwood and of alternative fuels which could be substituted for fuelwood.
Current fuel usage may be known from recent surveys in the area. If not, then it must be measured. If the fuelwood used is purchased then it may be possible to assess the quantities involved somewhere along the distribution chain, i.e., by recording how much is sold by the fuelwood merchants, or how many lorry loads, donkey loads, etc., are brought in for sale over a particular period, and how much wood there is in such loads. In the more usual situation, where fuelwood is gathered rather than bought, it is unlikely that useful estimates of use can be obtained except by direct measurement at the household level, by means of a sample survey. If the population to be surveyed encompasses areas or groups which arc likely to exhibit markedly different usage patterns (hill and valley locations, groups with different income levels, etc.), then a stratified sample survey should be designed which will allow these differences to be identified, and taken into account.
Weighing is likely to be the most accurate form of measurement of fuelwood, but care must be taken to record the type of wood, and whether it is green or dry, in order to be able to translate this weight information into equivalent volumes of standing wood. In most areas fuelwood use varies markedly with the season: in mountains more is needed in the cold season than the hot season, in the tropics less tends to be used in the wet season than the dry, etc. The measurements of usage must therefore be repeated at sufficient intervals to establish the nature and magnitude of this seasonal fluctuation, in order to arrive at a realistic estimate for the year as a whole.
The survey should also incorporate measurements or estimates of such other information as will be needed in assessing future change and alternative solutions to the fuel requirement. Such information might include some or all of the following:
- what other fuels are used, and in what quantities;- to what extent is the fuelwood used for cooking, heating, and other uses;
- is the fuelwood used in an open fire or a stove;
- is the fuelwood burnt green or dry;
- is there evidence of increasing fuelwood scarcity: rising prices, more hours per day spent on gathering it, etc.;
- is fuelwood gathered for sale as well as for own use; if so, how much and what income does it generate?
A fuelwood survey of this kind could well be carried out in conjunction with a household budget survey. As should be the case with all such surveys, its actual form and dimensions need to be consistent with the importance of fuelwood to the community. If it is going to be possible to provide ample fuelwood supplies with little difficulty, then rough estimates of the quantities needed will probably suffice. On the other hand, if there are severe constraints on the development of fuelwood supplies, such as acute shortage of land for tree growing, then the situation is likely to have to be studied in some depth. The survey should therefore be preceded by a preliminary assessment to establish the dimension of the problem, the type of information needed, and the factors that should be taken into account in designing and carrying out the survey.
In assessing how much fuelwood the community is likely to need in the future, it is important to consider whether requirements per household could be reduced. Fuelwood is traditionally used very inefficiently and most of the heat is wasted. If it could be used more efficiently, a given level of requirement for heat, for cooking and warmth, could be achieved from substantially less quantities of fuelwood, or of other fuels. To reduce fuel requirements, the important points are:
- the wood or charcoal must be dry and the stove for burning the fuel must be correctly designed; this is especially important for woods- open wood fires should be avoided; they are very inefficient;
- cooking utensils should be closed, especially when food is prepared by boiling and the use of pressure cookers makes for great savings in fuel;
- fuel used in colder climates may be indirectly reduced by improved housing to reduce draughts and heat loss through walls, floor and roof, etc., and by better clothing.
At the same time, it is necessary to recognize that in situations where fuelwood is already scarce, current usage may be below what is needed or desirable to maintain adequate levels of warmth or to provide sufficient cooked food. In these circumstances, if the necessary improvements cannot be effected by improving the efficiency of fuel use, an increase in supplies per household might have to be planned for.
In assessing what share of the community’s fuel requirements might be met from fuelwood in the future, the following points should be kept in mind:
1) Use of commercial fuels will depend in the first place upon their availability: the existence of a distribution network which makes them available within the community. However, even where they are available, they will be used only where the population is able to afford the costs. Because of the cash outlays required for stoves, installation, etc., these fuels may not be a viable option for the rural poor.2) Charcoal can be made from any woody material but dense charcoal which can be transported and handled easily requires wood of medium to high density. Because of the need to dry wood before carbonizing, charcoal production is more successful in low humidity climates. Charcoal is favoured as a fuel over wood because it cannot deteriorate in storage, is convenient to use, produces no smoke or tar and requires a simple stove. Its combustion efficiency considered at this point is usually higher than wood. However, there is a great loss in the carbonization of the wood to produce charcoal. Thus, use of wood for fuel as an alternative to charcoal should always be seriously considered. An important factor in the choice between fuelwood and charcoal is that the latter can be transported economically over longer distances. It could be possible, therefore, to draw supplies of wood fuel in the form of charcoal from wood sources too far away to supply fuelwood economically.
3) Agricultural residues and animal dung are direct substitutes for fuelwood, commonly used either when fuelwood is in short supply or seasonally when the residues are widely available. A factor to be taken into account in assessing the balance between these fuels and fuelwood is the possible alternative value of the residues and dung in maintaining the fertility and structure of the soil. Increasing fuelwood supplies could be desirable to avoid the loss of agricultural productivity that diversion of these organic residues to fuel would bring about.
4) Biogasification converts agricultural residues and dung to a gas fuel, methane, through anaerobic fermentation, while the plant nutrient value of the organic material is retained in the residues, which can thus be used as a fertilizer. It is, therefore, an alternative to be considered where fuelwood is in short supply, leading to an undesirable diversion of residues and dung to fuel use. Factors that could influence the choice between biogas and fuelwood are: cost of the plant and associated equipment to store and use the gas, a minimum size more suitable for community than household use, the need for assured supplies of water, and the technical knowledge required to maintain a uniform temperature.
The appropriate solution in a given situation could well involve several elements. It is important to bear in mind that a situation of fuelwood scarcity might be as significantly, and as quickly, alleviated by reducing demand, in one or more of the ways outlined, as by embarking on an afforestation programme to increase supply.
Poles and timber
In assessing local needs for poles or for sawn or hewn timber, where these are used as building materials in the community, a similar investigation to that outlined for fuelwood will usually be necessary.
As in the case of fuelwood, it will be important to take into account likely future changes in usage. For example, in East Africa a common early stage in the process of upgrading rural housing as incomes rise is the substitution of corrugated iron roofing for thatched roofing. To provide a proper base for corrugated iron it is desirable to use sawn timber members for the roof structure instead of poles. Therefore this trend in housing development is accompanied by a faster growth in needs for sawn timber than for poles.
Where a need for sawn timber is foreseen, the investigation should be broadened to cover an assessment of how sawn timber could best be produced locally from roundwood. This could be by handsawing, which is simple and inexpensive. Alternatively it might be possible to establish a email sawmill, or at least a powered saw, within the community. Details of types of equipment which might be suitable are given in Appendix 5.
There remain to be considered the many forest products, other than wood, which are in the forests and which may or may not be utilized by the local community. If forestry is to provide the maximum benefit to the community, it is important that the people should be encouraged and assisted to make the widest possible use of the available products, and made aware of others which might be introduced if the environment is suitable and markets are available.
Table 3 summarizes some forest products, the species which produce them and the benefits they provide, while Appendix 3 gives examples of a wider range of species and products with some notes on their distribution, production and uses. The products are grouped in three categories indicating in what ways they are likely to be relevant to rural community needs: provision of food, income generation and increased land productivity.
Provision of food
The role of forests in providing food for the rural community either directly in the form of seeds and nuts, fruits, shoots and leaves which can be eaten raw or cooked, or indirectly as fodder for livestock, or by providing environmental conditions suitable for wildlife and fish, is well known. In planning a project, the extent to which the community has drawn on these food sources in the past would need to be evaluated and the following factors would require consideration:
- the abundance and frequency of the tree species yielding edible products;- the origin of the tree, whether natural or planted;
- the period of the year when the product is available and most abundant (This may be of particular importance if it coincides with the beginning of the normal cultivation cycle or with adverse climatic conditions when food reserves may be low. If the product is sold as a cash crop, the seasonal price fluctuations and the reason for these should be established);
- the traditional rights of usage observed within the community.
The impact of these ‘secondary food sources’ on the stability of the community should also be assessed. The presence of stable communities practising shifting cultivation may be partly explained by the fact that they preserve trees which provide food in the course of their usual slash and burn practice.
TABLE 3
SOME OTHER FOREST PRODUCTS AND THE BENEFITS THEY
PROVIDE
|
Nature of product |
Type of product or species |
Time lapse between planting and harvesting |
Life span benefit |
Kind of benefits |
|
|
|
|
|
|
Main |
Secondary |
|
Food
|
Nuts - cashew, chestnut, Macadamia, Pistachia |
Short to medium |
Very long if protected |
Nut |
Fuelwood, poles, shade, fodder |
|
Nuts - brazil, pine, hazel, Canarium |
Medium |
Very long if protected |
Wood, fuelwood, shade |
Nut |
|
|
Fruits - jakfruit, mango, Durio, Garcinia, Ficus,
Tamarindus |
Medium |
Very long if protected |
Fruit |
Wood, shade, fodder |
|
|
Palm |
Medium if cultivated |
Very long for fruit and oil |
Fruit, oil, edible heart |
Leaves for fuel and roofing |
|
|
Fungi |
Short |
Renewable source if cultivated |
Mushroom |
|
|
|
Animal protein |
- |
Renewable if protected and managed |
Meat and fish |
|
|
|
Fodder |
Acacia, Prosopis, Albizia |
Short |
Medium |
Fodder |
Poles, fuelwood, bee forage |
|
Forest products providing employment or cash
|
Bamboo |
Very short |
Renewable by planting and good management |
Raw material for industries, handicrafts, handmade paper |
Shoots for food, forage |
|
Resin tapping |
Medium to long |
Sufficiently long if resources renewed after timber exploitation |
Employment |
Further employment if rosin and turpentine industry follows |
|
|
Tasar silk |
Short |
Forever if vegetation protected |
Income by harvesting silk |
Fuelwood, employment if silk industry follows |
|
|
Acacia senegal |
Short |
Renewable by planting and good management |
Gum arabic |
Fodder, fuelwood, poles, soil improvement |
|
|
Medicinal and other economic plants |
Short if planted |
Very long if protected |
Income and employment |
Impact on health (medicinal) |
|
|
Forest products which increase land productivity by diversification
|
All species which provide bee forage as well as wood, nuts or fruits |
|
|
Income and employment, honey |
Impact on nutrition |
|
Thea oleosa |
Medium |
Very long |
Oil, oilcake for animal feed |
Bee forage, wood for handicrafts |
|
Note: The species and products mentioned above are examples only.
Any programme for community forestry should therefore take into account:
- the food habits of the local people and their preferences;
- the conservation and development of all trees which yield edible products;
- the planting and management of fodder species;
- ensuring suitable environmental conditions for fish and wildlife.
Income generation
The natural resources available to the community might be able to support production of saleable outputs thereby providing cash income which will contribute to greater food security and a better standard of living. Some examples of such activities are:
- resin tapping of some pine and dipterocarp species which can lead to a local industry for the production of turpentine and rosin;- gum cultivation in combination with foodcrops and fuelwood products;
- use of natural shrub species for tasar silk culture which can lead to a local industry in silk handicrafts;
- beekeeping to take advantage of the nectar and pollen yield of plants to provide honey and beeswax.
Several non-wood products have great economic importance and can provide a fair share of the farmer’s income. Gum arabic in the Kordofan Province of Sudan is a good example, not only providing considerable income to the farmers but also having a significant impact on the national economy through its export earnings. Anacardium occidentale is another cash crop very suitable at the farmer or community level. The export prospects for the cashew nut are good with increasing markets in developed countries and also increasing world prices for both the nut and the oil. Other examples are palm hearts and bamboo shoot which already have an international market and for which, at present, the demand in developed western countries is greater than the supply.
In estimating the potential which could be created by this type of activity, consideration would need to be given to the manpower available and whether it would be full-time or seasonal, the resources available for each type of activity envisaged, the potential for the development of the resource and the availability of markets for the sale of the product.
If the activity selected depends on existing resources it will be essential to ensure proper management for maximum and long-lasting benefit. If new resources have to be developed, quick establishment providing a minimum time lag from planting to resource use would be desirable.
Increased land productivity
The needs for food, employment and income can best be met from resources which can provide a range of uses thereby increasing land productivity. Some examples of such multipurpose species are the many plants which produce nectar and pollen for honey production; bamboo, which is used as a simple building material, for handicrafts, for fodder, for the production of handmade paper and to provide shoots for human consumption; and such species as Acacia senegal and Thea oleosa which have a wide range of uses (Appendix 3). Other examples of multipurpose species, of which there are many, are given in Appendix 3. Rural communities could benefit considerably by the introduction of such species if they do not occur naturally and if conditions permit.
Many of the products that have been discussed are items that could or would be produced partly or wholly for sale rather than for local consumption within the community. There will be many situations where even fuelwood or other wood products might also be produced for Bale. It is very important that if the small producer is to be encouraged to engage in such production he be assured that he will be able to market the product, and market it at a profit.
A number of issues arise in this respect. The first is the need to be able to identify markets, to be able to match markets to the range of products that the farmer might produce and be able to assess the likely financial profitability to the producer through analysis of the value in the marketplace and the costs of producing the goods and placing them in the market. In short, the forest service, or whichever agency is encouraging new or expanded production, must base this on sound market intelligence. As some of the crops likely to be grown in community forestry projects have a lengthy production period, it may be necessary to assess what is likely to happen in the market some years ahead.
A second factor is the need to ensure that the producer benefits to the fullest extent possible. All too often, a disproportionately large part of the market value accrues to intermediaries. The latter also tend to encourage the producer in negative practices: for example, encouraging production of commercial products at the expense of essential protective practices.
One solution to this problem can be to encourage and assist cooperatives and other forms of producer grouping. It is to be noted that cooperatives, to be effective, usually need to be vertically integrated through to the marketing stage, and the maximum benefits will often only be achieved if they also engage in processing. Alternatively the forestry authority or a state forest corporation might undertake the marketing of their production on behalf of small producers. However, to be effective and efficient this calls for commercial and management skills which a forest authority may not possess. One way of overcoming this could be for the authority to set up a joint enterprise with industry for this purpose.
A related issue is that of ensuring stability of prices in order to avoid fluctuations in the income of the producer. Price controls, price commissions and buffer stocks are devices which might be appropriate in particular situations. However, with a few notable examples such as gum arabic in Sudan, the proportion of the production of a commodity which is generated through community forestry projects is seldom likely to be so large as to warrant a separate price control mechanism, and price stabilization measures would normally have to take place as a part of the machinery for stabilization of prices of agricultural products in general.
Other distribution and marketing issues include availability of credit, which has been discussed on page 23, and access to markets. Community forestry projects often involve populations in remote areas which lack even physical access to markets. The forest authority may have to accept the responsibility to provide such access through the building or upgrading of feeder roads to link the community with the existing transport network.
The following sections consider the services rendered by forestry which are frequently insufficiently known to the local population, and comprise such benefits as erosion control, soil conservation, watershed protection, stream flow regulation, dune fixation and local modification of wind, temperature and humidity. These are immense topics of enormous complexity, the treatment of which is covered by numerous publications some of which are listed in Appendix 6. Of particular relevance are two papers (FAO 1977 (a)(P) and FAO 1977 (b)(P)).
Erosion control, soil conservation and land reclamation
In areas with a high erosion hazard, because of the type of soil, steep slopes or because of the distribution and intensity of rainfall, both the establishment of annual and permanent crops and the establishment of tree plantations require the adoption of suitable conservation techniques. On very steep slopes, where intensive conservation farming techniques, including bench terraces, cannot be established, only perennial plant cover can ensure protection. Rural communities are only likely to undertake protective measures if they see disadvantages to themselves in failing to do so (for example where torrents from above deposit debris on arable land), or when they anticipate benefits in the form of production. Incentives, such as subsidies or soft credit, may be necessary for the introduction of conservation practices in most cases.
In the protection of public facilities, the involvement of the community should be encouraged but the total economic burden should be the responsibility of the government. Such would be the case with mountain roads which are affected by landslides and gully erosion, the prevention of silting in canals and reservoirs, and the protection of human settlements against floods through river training.
Land reclamation and erosion control schemes may secure unemployed or underemployed people with a regular income during the periods in which agricultural or forestry activities cannot provide full employment. Some of the possibilities to be considered are sand dune fixation, establishment of shelterbelts, road protection, desiccation of swamps and reclamation in arid zones, saline soils, lateritic plains or badly eroded areas.
Effects on local climate and hydrology
Trees affect the climate in their vicinity by reducing wind speeds at ground level, and by shading the ground, which causes heating to be raised to canopy level. Where forest maintains a deep soil that otherwise would be unexploited by roots or eroded away, the resulting retention of water for local evaporation makes for lower temperature and higher relative humidity than would prevail if the forest was absent. Shade and shelter have been known and appreciated from time immemorial, but some of the effects on the cycles of water and energy are only now beginning to be realized, even by specialists. Villagers are unlikely to wish to plant trees only for their climatic effects, but these may constitute a useful subsidiary argument.
Amenity aspects
Restoration of an area to scenic beauty will contribute, in addition to the psychological, esthetic and physical benefits on the community involved, to making it more attractive to tourists through the improvement of landscapes and the establishment of recreational possibilities. The implementation of recreational facilities will provide additional employment and cash income to the local community. A pleasing landscape, in the place of eroded slopes and a wildlife-depleted habitat, will certainly give the community an outlook that will be very different from the attitude of resignation, poverty and disease that is characteristic of communities where the natural resources have been misused and abused.
Tree plantations may also be established in waste and sewage disposal areas, thus making better use of the land, preventing wind- and water-borne diseases from affecting neighbouring areas and promoting the recycling of water and nutrients.
Wildlife management
Wildlife can also contribute to the development of local communities, either by providing food or other products or by becoming a source of attraction for tourists and for gamehunters. Crocodile-rearing in village pens and the management of deer for the production of antlers are two of the many possibilities which are discussed in more detail in Appendix 3.
Introduction
Multiple-Product Forestry
Small-Scale Forestry (‘Village Woodlots’)
Agrisilviculture
Silvipasture
Integrated Watershed Management
To satisfy existing and potential needs, once these have been identified, production systems must be set up. These will rarely be as simple as the systems of classical silviculture if the associated products mentioned previously are to be integrated into them. Where the need for land for food production is very great, forestry may only be acceptable if it is combined with agriculture or grazing in an integrated system.
It is convenient to treat the many possible combinations of productive systems under a few main headings, comparable with the silvicultural systems of classical large-scale forestry. There is a problem of terminology, several terms being used in some cases for a single system and a single term in others for several. For example, ‘agri-silviculture’ is sometimes used to mean any combination of annual crops with trees and sometimes to mean the particular method of plantation known as ‘taungya’ (i.e., planting of forest trees by farmers who are paid partly or wholly by being allowed to grow foodcrops between the trees in the initial years). More recently the term ‘agro-forestry’ has been introduced to signify any system that includes both tree cultivation and food production. In the present document an attempt is made to use terms that are precise and unambiguous and that lend themselves to translation.
All the systems described below have in common the feature of yielding products that can either be directly consumed or easily harvested and marketed by the local community. At one extreme (small-scale forestry or ‘village woodlots’) this result is assured simply by scaling-down and adapting classical silviculture. At the other extreme stand complicated systems that combine two or more simultaneous or consecutive productive sub-systems.
The main categories are as follows:
- multiple-product forestry,
- small-scale forestry (village woodlots),
- arboriculture (tree farming),
- agrisilviculture,
- silvipasture.
This study has taken into account the experiences of 18 projects, which are summarized in Appendix 2. 1/ Twelve of these were examined in detail in the Desk Study presented at the Second Expert Consultation in June 1977 and six were individually tested as case studies by participants in that meeting.
1/ Two of the projects have been summarized jointly.
Fourteen of the projects fell into the category of ‘small-scale’, two into agrisilvicultural/taungya, one arboricultural and one into silvipastoral. The major objectives of the projects were as follows:
1 pulpwood production
1 gum arabic production
2 fodder production
5 fuelwood production
9 timber, poles and fuelwood production.
Eight of the projects were strongly motivated by environmental protection and improvement, five by social considerations and one envisaged integrated multi-product forestry.
This term is used to cover all cases in which a forest ecosystem is made to yield other material products in addition to wood (but net including annual crops, forage for forest grazing, nor such products as water that would be produced under any system). At one extreme this may mean no extra management provisions other than perhaps facilitating access, as with honey production amongst eucalypts. At the other extreme complex manipulation of the ecosystem may be necessary. In between lie a range of possibilities in which the forester treats the requirements of subsidiary production as constraints on silviculture.
Multiple-product systems are particularly indicated where the local inhabitants are forest communities with a tradition of obtaining a variety of products from the forest, and where past management has aimed exclusively at timber production to the detriment of the people’s livelihood. In the case of plantation forestry it seems likely that only the simplest provision of secondary products can be catered for, at least in the first rotation.
This is silviculture on the scale dictated by local demand for forest products and local availability of suitable land. There is a single main product, normally firewood, and the techniques of cultivation are simple. Skilled advice is likely to be necessary only on establishment and harvesting. The loss of the land for other uses will be felt during the more or less lengthy period before production starts, and some form of compensation is called for. Because of its simplicity this system is the most suitable for peoples with little tradition of cultivation, notably the grazing communities of relatively arid lands, and for farming communities that rely on a single main-crop plant.
An important sub-class is constituted by line or group plantations, in which the trees are dispersed in small groups or lines wherever suitable patches or bands of land are available. The purpose nay be to provide wood or shelter or both. Management of a set of such groups as a single wood-production unit is clearly more difficult than the case of a single block, and protection of the young trees against damage requires greater awareness and discipline. This type of plantation is therefore suitable for communities with a strong tradition of cultivation and crop protection.
It is also convenient to treat under this heading the intensive plantation of fast-growing trees for wood production by private owners, though this category merges into that of arboriculture (see below). Quick-growing species such as Gmelina arborea and Albizia falcataria can be regarded as cash crops. A plantation of Gmelina after 8 years can yield 200 m3/ha which may give a return which is as much as the return from several agricultural crops. The additional advantages are threefold: (i) earnings become regular, (ii) cropping may continue for a long time under a coppicing system, and (iii) soil fertility is maintained.
Other cases of trees as cash crops using Casuarina spp. on sand dunes, various species of bamboo, or cashew (Anacardium occidentale), can be found in many countries.
Arboriculture
This term is used to signify the intensive cultivation of trees individually or in small groups or orchards for whatever purpose. 1/ Arboriculture is a bone of contention between foresters and agriculturists. Where the crop is edible the latter have usually succeeded in taking charge, though there are many cases of forest services planting fruit or nut trees, particularly if there is novelty (for example, carob trees). Where the crop is not food, the allocation to foresters or agriculturists has been arbitrary. For example the former has kept cork oak while the latter has had rubber.
1/ The English-language usage in industrialized countries, restricting the sense to the tending of ornamental trees, often in an urban context, is derived from this original meaning.
Rules for allocation do not seem to be possible or useful. Foresters should adopt a pragmatic approach and be ready to help to introduce or improve arboriculture wherever no one else is acting. All the trees of agriculture initially came out of the forest, and if the forester can get promising new species out into fields and orchards he should do so.
Arboriculture is skilled work and is unlikely to be successfully undertaken except by farming or forest communities with a tradition of planting, grafting, pruning and tending trees.
General
This term is used here to cover all systems in which land is used to produce both forest trees and agricultural crops, either simultaneously or alternately. Where the agricultural component comprises food trees this category merges into multiple-product forestry, the distinction depending on the ownership and the intensity of cultivation. Their complexity makes these systems fragile, and they tend to simplify themselves either into plain agriculture or to plain forestry. And for the same reason they are more likely to succeed with communities that have a tradition of cultivating both trees and annual crops, Several major systems may be distinguished.
Agriculture with tree fallow
This is simply an improved version of that most ancient system, shifting cultivation, the trees of the fallow being valuable species, planted or sown instead of being allowed to spring up spontaneously. As with the shifting cultivation, the problem is that increasing demand for food may lead to the fallow period being shortened or eliminated altogether. The solution, to be adopted wherever the forest fallow is necessary for the maintenance of the soil, is to increase the productivity of one or other or both phases and to inform the farmer of the hazards of soil degradation. This system is most likely to be appropriate for forest communities but where a particularly valuable forest product is available it may also be proposed to farming communities. In southern Iraq a system is practised which can be counted in this category: tamarix trees are planted on land which was once used for growing vegetables and was later abandoned after the well water had become very saline.
Agricultural afforestation
This system consists of intercropping a forest plantation with agricultural crops in the initial years, until the canopy of the forest trees closes. In principle this system may be used on any suitable land, irrespective of ownership, and with labour provided by paid workers. In practice, however, it has been used mainly as a method of afforesting publicly owned land, using the labour of land-hungry farmers who are paid wholly or partly by being given the use of the land: this is the well-known taungya system, first used in Burma in 1856 and since adopted in various forms in many countries. It is important to note that taungya is only one possible method of agricultural afforestation. This system should not be used in hilly areas with steep slopes, unless special management is introduced.
It is logical to assume that if agricultural crops are to be grown in conjunction with forest crops, and if forestry is to be the dominant land use from the inception of the plantation, the tree species that are used should preferably be chosen because they display silvicultural characteristics that would permit them to compete effectively with the agricultural crops, namely:
- they should be fast-growing light demanders so that they may quickly over-top the foodcrops;- they should either be capable of closing canopy early or should be capable of being planted at close spacements to allow early crown closure;
- their root system should not be superficial thus making them liable to root damage from the cultivators;
- they should have the overall ability to withstand short periods of competition for light, water and nutrients.
By the same token, the agricultural crops should also possess certain features:
- they ought not to cast too much shade;
- they should not be climbers unless the farmers provide supporting sticks for climbing plants;
- their nutrient requirements should not be such that they rapidly exhaust the soil;
- if rhizomes, they should not have the propensity to spread rapidly;
- their period of gestation, and continued production, should not be so long that competition from them is prolonged.
If possible, the agricultural crops should also display certain qualities, advantageous to the tree crop, such as those of soil improvement (through the fixation of nitrogen, for example) and water conservation.
These general propositions are based on the assumption that the main goal is to establish a tree crop as soon as possible. However, because of socio-economic reasons, it may be desirable to assist the farmer as long as possible, making a compromise between the agricultural and the forestry objectives. In such cases the tree species should be amenable to early wide spacement, should possibly possess self-pruning properties, should not cast a dense shade and should themselves be tolerant of side-shade, if not full overhead shade, in the early stages. (King, 1968 (S)).
The system begins with the clear-felling and burning of either the remains of a recently exploited forest or of the secondary growth. However, some valuable tree species may be marked for retention, as is done in some parts of Sierra Leone. In most cases the first agricultural crops are planted before the tree crop, but they may be planted after the tree crop, or simultaneously. The actual time of planting of both types of crops is regulated by the rainfall regime of the area concerned. Where agricultural planting precedes forest planting the objectives are to provide an incentive to the farmer to clear the land, to give the farmer a period of use during which he is not burdened by the necessity of caring for the forest crop, and to ensure that the land is properly cleared before the forest crop is introduced. But it is also true that when the two crops are planted simultaneously or the agricultural crop is planted first, the trees will receive an initial boost in growth from the burnt vegetable matter and the farmer will be more careful in his tending of the trees when his own crops are giving returns, since his interest in the tree crop will be related to the yields of his agricultural crops.
A few examples of particular agricultural afforestation systems are given in Appendix 4, together with a list of agricultural crops most commonly grown in the geographic regions where taungya is most frequently practised.
Perennial crops under forestry
In many countries the cultivation of tree crops or other perennial crops other than timber species are proscribed in forest reserves for various reasons: they suppress the forest crops; they encourage the farmers to stay on after the forest trees have grown up; they compete with the forest species for water, nutrients and crown space; in the event of forest trees being found to be hosts for pests which attack the agricultural crops, there will be irresistible pressure on the Forest Service to destroy the timber crop; and they may lead to claims for ownership or rights and other claims against the Forest Service. The agricultural tree species which are sometimes grown with forest species include cocoa, coffee, oil palm, citrus, papaya, rubber and tea.
This term covers systems in which controlled grazing of forest vegetation takes place during part of the rotation. It does not extend to destructive overgrazing such as is currently practised in large areas of the world’s forests. Nor does it include the growing of fodder crops that are harvested and fed to stalled animals: this is classified as agrisilviculture even though animal husbandry is involved, since only plant production takes place in the forest. The transition from unmanaged grazing to silvipasture is one of the roost difficult tasks facing rural authorities in grazing communities, but the only alternative is to watch further losses of biological capital. The principle considerations which must be the basis for all grazing management programmes are the following:
Proper intensity of use - Plants thrive when the degree of use is moderate, Enough of the herbage and browse production mist be left to permit the plants to keep their food factory productive and to provide for ground cover, and the return of organic matter to the soil. A general estimate is to utilize 50 percent and leave 50 percent.Proper season of use - Grazing during rapid periods of growth is especially damaging. The most critical period is soon after growth starts on a given range and the animals must be kept off at this time.
Uniform livestock use over the range - Livestock tends to use some areas more heavily than others especially near water, along level bottomlands, ridges and certain range sites. To attain uniform livestock use would require well-planned water development, establishment of division fences and construction of trails in rough and bush country. Salt may also be used to some extent to attract livestock to areas which would otherwise be little used. Assigning the class of stock to any given locality according to forage preferences of the animals is also very important. Goats for example can do well on leaves and twigs of brush and dwarf timber species. Horses need grass. Sheep sometimes do well on weeds. Cattle will take a certain amount of browse from brush species in addition to grass which they prefer.
Periodic rest from grazing - Year-long use of ranges places the range plants at a tremendous disadvantage since they have little opportunity to make root growth, replenish carbohydrate reserves, initiate new shoot or to meet a combination of these growth requirements which could not be met under a yearlong grazing period Rest during any part of the year is therefore important but it is especially essential during early stages of growth. Many systems of deferred and rotation grazing have been developed to permit the plants to rest during part of the year. However, any successful system must fit the local conditions if it is to be of any value.
Good livestock husbandry - A correct grazing management programme should not be an end in itself. Any grazing management programme should aim at increasing meat production. This requires that special consideration be given to the improvement of the methods of herding, removal of marketable stock, to avoid shrinkage in weight, to improvement of the strains of grazing animals and the eradication of insects and plant pests.
Where range lands have been completely depleted as a result of overgrazing, conservation and improvement action should be undertaken. To this end the programme should include the following steps, in this order; 1) reducing the number of animals grazing in the particular range; 2) preventing farther erosion and repairing erosion damage; 3) improving fodder production by reseeding or replanting the range where necessary; 4) adopting a set of good management practices, which may include such requirements as provision of water, rotating stock on range sub-divisions by means of fences, eradication of unpalatable species and careful observance of grazing seasons.
Major work has been done on fodder improvement in forest plantations in Papua New Guinea, including studies on grazing rotations, carrying capacity, economies of integration, etc. In the Araucaria forest pastures in Bulolo about 2 000 head of cattle are grazed in some 4 000 ha of forest plantations. While cattle are now introduced in open plantations of above seven to eight years of age, it is expected that this can be done even in plantations over three or four years old. Fencing would be required to prevent cattle straying into younger plantations.
In Indonesia, the State Forest Corporation (Perum Perhutani) has been investigating since 1973 the productivity of elephant grass (Pennisetum purpureum) under teak and mahogany plantations in the National Forests. Also, on private land in the Upper Solo watershed, with technical advice from UNDP/FAO, underplanting of elephant grass is carried out at 0.3 × 0.8 metres (m). Trees are planted at 2 × 2 m spacing, the choice of species varying with climate: Pinus merkusii, Albizia falcatari, Eucalyptus alba, Acacia auriculiformis and Calliandra calothyrus. The elephant grass density is increased by the farmer by planting cuttings during the first two years and full production of 60 tons/ha/year is attained in year three, but yields of 140 tons/ha/year have been reached. The Pinus/Albizia/grass system would employ two men on a full-time basis on a 1 ha holding. The Eucalyptus/grass system would employ one man per hectare continuously, but in the area where this system could be used, holdings are often 2 ha in extent.
In Nepal, fodder plantations are generally multi-purpose, the main species being Ficus cunia, F. lacos, Albizia spp, Litsea polyantha, Morus spp, Caetanopsis spp, and Leucaena glauca. Seven hundred to fifteen hundred trees per hectare are planted and harvesting commences some five years after planting, full production being obtained in the tenth year. Tree foliage is harvested all year, but particularly after the monsoon season. A farmer’s estimate is that one mature fodder tree will provide supplementary feed for a cow or a buffalo for one month. A buffalo will eat up to seven tons of leaves per year, which comprises 41 percent of its feed, and a cow will eat up to 2.5 metric tons, comprising 27 percent of annual feed. Other estimates of annual yield are 5.7 metric tons of starch equivalent or 26 metric tons of dry matter per hectare and 5-12.5 metric tone of leaves per hectare.
In the Sahelian zone, an effort is being made to regenerate and enrich the savanna for grazing purposes. In Senegal, in the Cap Vert area (annual rainfall about 350 millimetres (mm)), Acacia albida is planted at a 10 × 10 m spacing. Felling is prohibited and there is no specific fencing against cattle. Guards or watchmen are used to protect recent plantings.
Comprehensive watershed management is in fact a complex of systems which is geared toward four main objectives:
- the rationalization of the land-use pattern, according to the land-use capability and other environmental criteria;- the optimization of the use of natural renewable resources, within the concepts of multiple purpose use and continuous yield of goods and services;
- the protection of water resources quality, quantity and timing and the conservation of the soil’s productivity;
- the improvement of quality of life, both for the benefit of local communities as for other human settlements which are dependent on the watershed’s resources and on the stability of the tributary area.
Therefore, integrated watershed management requires the combined input of all pertinent rural development actions plus a series of specific actions which may involve the application of one or more of the following measures and techniques:
- preventive regulations,
- manipulation of the vegetation cover,
- mountain road stabilization,
- afforestation and revegetation,
- torrent control,
- conservation farming,
- range management.
Intensive erosion control works for improved upland agriculture can be justified in areas with a high pressure for agricultural lands, as has been demonstrated in a UNDP/FAO pilot watershed project in Smithfield, Jamaica. The steep slopes were systematically terraced and fruit and forest trees were introduced, with excellent returns, particularly from harvests of lucea yam and yellow yam (Dioscorea spp). Net returns of US$ 1 875/ha were obtained, the annual cost of bench-terracing being US$ 200/ha with soil improvement practices. At the same tine, the amount of soil loss, as compared with the traditional cropping systems, is greatly reduced with terraces. In the same project a comparison was made of the two methods during four years on a 17° slope (annual rainfall 3 250 mm), which showed that the average of dry soil loss per hectare per year from the check plot was 135 tons, while the loss from the bench terrace plots was 17.5 tons. Plots with hillside ditches with continuous mounds lost 27.5 tons (FAO, 1977 (S)).
In the Mae Sa Integrated Watershed and Forest Land Use Project in Northern Thailand, the objectives of soil and water conservation and also important social objectives are being attained by an integrated effort comprising:
- stabilization of shifting cultivators as settled farmers through incentives, demonstration and extension;- improvement of the living standards by adjusting the population/natural resources ratio and by introducing new crops, new cultivation practices, education and health measures, market promotion, security of land tenure according to the availability of land, etc.;
- employment for the landless and those leaving the rural areas, training of local staff, introduction of labour intensive activities and improvement of the physical and institutional infrastructure.
Small farmers practising subsistence agriculture in steep upland areas, who progress uphill as the soil is depleted, are generally reluctant to establish conservation farming systems, for in establishing bench terraces, for instance, they would initially lose a crop. In the case of the Upper Solo project in Indonesia, food aid from the World Food Programme enabled the farmers to establish bench terraces. In Tunisia, credit from the Government and food aid enabled the farmers to do likewise.
Subsidies may be a convenient incentive for integrated watershed management projects, as has been shown by 20 years’ experience in Venezuela, particularly in the Andes, through a successful conservation subsidy programme. Afforestation, contour ditches, check-dams and other erosion control practices are encouraged through payment in kind of fertilizers, seeds, livestock, sprinkler irrigation equipment, construction material and other inputs which rapidly allow the small landholders to increase productivity and to improve their standard of living.
The integrated approach is particularly pertinent in the case of watersheds. The upper watershed and the downstream area should be complementary and a socio-economic balance should be maintained. Since the community is unlikely to take the initiative in this type of effort, the government should take steps to establish the necessary authority for interagency cooperation but involving the community as much as possible.
Introduction
Silvicultural Considerations
Utilization Considerations
Environmental Considerations
Implementing the chosen production system requires detailed choice of site, species and technique, though to treat one decision as subsequent to the other is merely a didactic convenience: normally the system will have been chosen with the available options in mind and these will have been selected in the course of the survey on needs and possibilities. It is therefore not necessary to reiterate considerations that have already emerged. Thus the issues that arise in ensuring that production is economically sound, that were discussed on pages 38 and 39 are not repeated here. Nor will the following outline include much of the detail that is to be found in standard handbooks (see Appendix 6). Table 4 shows, in simplified form, the various considerations which need to be taken into account in the selection process, and this is followed by sections which describe the principle of selection giving some examples.
The choice of species is dependent on local conditions for growth. Local environmental conditions nay, for convenience, be divided into:
Site - That part of the local environment which it is difficult, or impossible, for man to alter, e.g., climate, soil depth, topography. In the present context ‘site’ is considered to include climatic as well as soil factors.Cultural treatment - Techniques used by man which can alter the local environment significantly, e.g., soil preparation, fertilization, weeding. Such techniques may have only a temporary effect, but they are usually applied at that stage in the life of the trees when it is most effective, i.e., the establishment stage, when the trees are young and most responsive to man’s intervention.
Because the choice of species should never be made without considering the characteristics of the site to be planted and the cultural techniques to be used, these are dealt with first.
Site
The effects of extreme differences in site are self-evident but even within a restricted area where a species is capable of surviving and growing, local differences in climate and soil can have considerable effect on its rate of growth and yield of produce. An example is Pinus radiata in South Australia, where volume production on the best site planted (S.Q.I.) is nearly four times that on the poorest (S.W. VII).
In slower growing species in north temperate conditions the ratio lies between two and three (e.g., Scots pine and Sitka spruce in U.K.).
The better the site (adequate rainfall, warm temperature, deep and fertile soil), the wider the range of species which will flourish and the greater the difference between the inherently fast-growing and the inherently slow-growing species. As conditions approach the limits of tree growth, for instance because of increasing aridity or increasingly low temperature, the number of successful species becomes fewer and their rates of growth and yield are reduced.
TABLE 4
CONSIDERATIONS IN SELECTION OF SITES, SPECIES AND
TECHNIQUES
|
|
|
|
Remarks |
|
SILVICULTURE |
Site |
Climate |
|
|
Cultural treatment |
Weeding |
|
|
|
Species |
Adaptability |
Local experience and research |
|
|
UTILIZATION |
Fuelwood |
Heating value |
|
|
Poles and posts |
Straightness |
|
|
|
Sawlogs, plywood, etc. |
Long rotation |
In general not suitable for community efforts but could be exceptions
(See Appendix 5) |
|
|
Pulpwood |
Short rotation |
See PICOP, page 54 |
|
|
Multipurpose species |
Producing several products simultaneously |
See Appendix 3 |
|
|
ENVIRONMENT
|
Shelterbelts |
Adaptability |
|
|
Sand dune fixation |
Adaptability to macro and microclimate |
|
|
|
Watershed management |
Good survival on impoverished sites |
Pioneer species better adapted to harsh sites |
|
|
Riverbank/Road-side protection |
Strong, dense and widespread root system |
|
Climate: temperature, rainfall, relative humidity, wind, elevation aspect, exposure. Seasonal and annual variations in temperature and rainfall are more important than totals or means. Length of dry season and its relation to temperature (‘summer’ or ‘winter’ rainfall regimes), mean daily minimum temperature in the coldest month and maximum in the hottest month are factors which may be limiting for certain species.
Soil: depth, texture, parent material, fertility, pH, salinity, degree of compaction or permeability, aeration, water relations and drainage. Of these, soil depth is usually the most important for tree growth, followed by soil texture.
Topography: important because it may have a considerable effect on both local climate and local soil development or soil erosion.
Biotic factors: influence of man, fire, domestic and wild animals, pests and diseases and competing vegetation. The effects of these may be modified by cultural or protective treatments.
Plant indicators: the existing vegetation, being itself the result of the interacting factors of climate, soil, topography, historical and biotic factors, may give valuable indications as to the characteristics of the site.
Accessibility: Planting sites close to the community have big advantages in the saving of transport costs and in facilitating planting and tending. In some cases a relatively poor quality site close to the community may be preferred to a higher quality, but more distant, site.
Within rural communities the scope for site selection for forest plantations is limited because the best sites are often reserved for agriculture. Within the forestry area, however, the assessment of the above factors should assist in selecting species adapted both to the general climate of the area and to the local soil variants, such as ridge tops and valley bottoms.
Cultural treatment
The intensity of cultural and protective treatment of planted trees affects both survival and growth. In some cases treatment may make the difference between success and failure, e.g., the exclusion of stock from newly planted palatable species, the addition of zinc to pine plantations in Australia or of boron to eucalypt and pine plantations in Africa. Species differ in their response to treatment: for example, eucalypts respond to weeding much more strikingly than do pines, to such an extent that weeding may make the difference between success and failure in eucalypt plantations.
For tree-planting in rural communities reliance should be placed, as far as possible, on relatively simple techniques, since it may be impossible to ensure the close technical supervision demanded by more sophisticated techniques. However, certain minimum standards are obligatory if it is to be worth planting at all. Adequate pitting is necessary whenever potted stock is to be used and it is essential to protect young trees from browsing by goats and cattle, and from fire, which can be a serious hazard, particularly if weeding is neglected.
Species vary in their silvicultural demands and detailed information is available in the various references listed in Appendix 6. Certain techniques which succeed with some species can result in failure with others, for example Cassia siamea is often established successfully by direct sowing, a technique which is entirely unsuited to the smaller-seeded eucalypts. The local possibilities for cultivation and protection will exert a considerable influence on the choice of species. Where the necessary technical advice is available, it should be possible to introduce immediately species which need intensive culture but which, given it, will produce large yields of products or services.. If conditions are very difficult or technical advice is not readily available, it may be necessary to select a ‘tougher’ but somewhat slower-growing species, at least in the early stages.
Selection of species
A species selected for planting should possess the following silvicultural characteristics:
1) Ability to survive and remain healthy under the given conditions of site and cultural treatment. Adaptability to local climate including annual variation in climate, and to a range of local soil variation.2) Resistance to local hazards, including pests, diseases, fire, browsing and trampling.
3) Ease of seed procurement, handling and storage.
4) Ease of handling in the nursery and establishment stages.
5) Ease of regeneration for later rotations, e.g., the advantages of coppicing or prolific seeding species.
6) Absence of undesirable biological side-effects such as the harbouring of agricultural pests or competition with agricultural crops by surface-rooting species.
7) For production planting, biological productivity under the given conditions of site and cultural treatment. In the case of wood production, yield data are commonly expressed in terms of volume.
8) For rural communities, productivity in the early years is more important than later productivity, since it allows short rotations and early returns on the initial investment in planting. ‘Quick starters’ are preferable for this and most of these are ecological pioneer species, rather than members of climax communities.
9) For protective planting, special characteristics may be required: e.g., crown shape for shelterbelts; rooting system for soil stabilization.
In deciding on the species best suited for planting in rural communities, as much use as possible should be made of local experience and research within the country. Rural communities seldom have the facilities to conduct their own research, but often it is possible to make use of research carried out by the national forest service, universities, etc. Where additional applied research does prove necessary in order to identify appropriate species and techniques, it should be carried out in conjunction with the local people.
In the case of exotics, which play an increasingly important role in plantations, useful guidance may be obtained by matching local climate and soil with those of other areas where a given species has performed well as an exotic. Comparison with site conditions within the natural range of the species is also useful, but gives less Indication of its adaptability to new environments than does its performance as an exotic.
There is much evidence that, for certain species, the provenance or geographic location from which seed was collected may be as important a factor in adaptability and rate of growth as the taxonomic species itself. A good example is Eucalyptus camaldulensis, of which the Lake Albacutva provenance in Victoria has given outstanding results in the Mediterranean region, while the Petford and Katherine provenances have performed excellently in savanna conditions south of the Sahara. Where such knowledge is available, it may be as important to select the right provenance as the right species.
The function of rural plantations is to provide either products such as food, fodder and wood, or services such as soil stabilization, shelter and shade. Any successful species can fulfil at least two purposes because 1) all trees produce wood and all wood can be burnt as fuel, 2) all trees produce roots and all roots are beneficial in reducing soil erosion and improving percolation of water. The versatility of a species in fulfilling more than one function simultaneously should always be assessed and, other things being equal, multipurpose species should be preferred to the single or dual-purpose species. It is, nevertheless, necessary to attempt quantitative comparison of the different functions separately. In some cases it may be more efficient to plant several species, each performing a separate function. A range of species may be less prone to pest and disease hazards than monocultures of a single multipurpose species.
Fuelwood
Fuel is likely to be the most important and the most universal of wood products obtained from rural community plantations. Even where a plantation is intended to provide other products such as poles or pulp, inferior material, suitable only for fuelwood, will make up a significant proportion of the total yield.
In addition to the silvicultural characteristics listed previously, such as high yields and quick growth, the following utilization characteristics are important in choosing species for fuelwood production.
1) Heating value. The heat produced by unit volumes of wood of different species is determined by the factors of specific gravity, moisture content and extractives. Of these, differences in specific gravity are likely to be the most important in modifying any choice of species based on volume yield per hectare. Moisture content and extractives are lees important, although the former may have a significant effect on handling and transport. Further details of these factors are:a) Specific gravity (S.G.). For wood at a given moisture content, heating value is directly related to specific gravity. Comparisons may be made at different moisture contents, of which ‘oven-dry’ (0 percent) and ‘air-dry’ (12-20 percent) are those most commonly used. Although air-dry specific gravity varies by a factor of eight between the lightest (Ochroma) and the heaviest (Piratinera) species in the world, the ratio between alternative species likely to be grown for fuelwood on the same site is unlikely to exceed two. It should be noted that specific gravity in fast-grown short rotation crops may differ considerably from that in mature natural stands. An example is Eucalyptus grandis, which has an air-dry S.G. of 0.82 in natural Australian stands but only averages 0.55 in plantations in South Africa.b) Moisture content (m.c.). Freshly felled wood usually has a m.c. of between 50 percent and over 100 percent. A given volume of average density species (S.G., 0.5) if dried from the ‘green’ (100 percent m.c.) to the ‘air-dry’ (20 percent m.c.), loses 40 percent of its weight and gains 16 percent in heating value (the 16 percent would be needed to evaporate the additional moisture if burnt green). The gain in heating value is less important than the saving in weight, an important factor if much handling or long transport hauls are involved.2) Ease of harvesting: e.g., disadvantages of crooked or thorny species. Harvesting costs per m3 are inversely related to volume per hectare. Thus a more productive species will not only need less land for a given yield than a less productive species, but will also be cheaper to harvest.The moisture content of green wood tends to be higher in the lighter woods, in which there are plenty of air spaces, than in the denser woods. As a general rule, therefore, a species which would be preferred for its higher S.G. air-dry, is likely to be even more superior if used green.
c) Extractives. The higher the percentage of extractives (oleo-resins, etc.) by weight, the higher the available heat per unit weight of wood. Differences rarely exceed 10-20 percent, even between the most resinous coniferous species and the more resin-free hardwoods.
3) Durability. Where it is necessary to dry fuelwood before use, its natural durability may be important in reducing losses from termites, borers or fungi.
4) Special characteristics. Certain characteristics of a potential fuelwood species may become limiting for particular uses. Emission of sparks is a disadvantage in an open domestic fireplace or when burned in proximity to inflammable buildings. Odour from combustion may rule out the use of certain species for cooking, fish drying and tobacco curing. Neither characteristic would matter if the wood was used in a furnace for production of mechanical or electrical power.
The following example illustrates the sort of evaluation which may be made when considering alternative species for fuelwood species. Both Eucalyptus grandis and E. paniculata thrive in similar conditions in Africa on warm, moist, frost-free sites. Published data (Wattle Research Institute, 1972) indicate that the volume yield of E. grandis is about 2.1 times that of E. Paniculata. But the specific gravity of E. grandis at 10 percent m.c. is only 0.6 that of E. paniculata, the m.c. when green is twice as much and the heating value per m3 green, is only 0.57. The net advantage for fuelwood is with E. grandis, but only by 20 percent. E. paniculata is much more durable than E. grandis (less loss in drying) and is in considerable demand for durable poles. Both species coppice well, are resistant to the snout-beetle Gonipterus and produce excellent honey. E. grandis, being a quick starter, closes canopy and shades out weeds more quickly and is thus easier to manage in the establishment stage. In this case, it is probable that E. paniculata would be favoured where there is a demand for durable poles, E. grandis where there is not. As an insurance against unforeseen hazards, it would be wise to plant a proportion of the area with each.
Poles and posts
These products are usually for local use. Straightness, strength and natural durability, or suitability for impregnation by one of the cheaper methods such as the hot and cold tank are the main desirable characteristics. Where there is a local demand for telephone poles, suitable species may provide a valuable cash crop with excessive rotation length. If there is demand for a variety of sizes of pole and post, this may simplify management. For example, thinnings of coppice snoots may be used for small posts or poles, leaving one shoot per stool to be grown on for telegraph poles.
Pine and eucalypt species have proved successful in plantations for producing poles and posts. Teak and Acacia spp, particularly A. mearnsii, are also used. Preservative treatment is necessary in each case, because the wood of plantation grown trees is rarely durable in the ground. In wet tropical areas preservative treated hardwoods, especially eucalypts, have given serious decay problems due to soft rot. Experience is now favouring softwoods, especially pine, in these situations.
Sawlogs, plywood, etc.
These products can be produced best from comparatively large, and therefore old, trees. Rotations usually need to be long, of the order of 23 to 30 years or more, and returns on investment are delayed. In addition, the management of the plantations may call for considerable skill, since provision must be made for operations such as pruning and thinning. Rural community plantations will therefore seldom be planted for these purposes. However, under good climatic and soil conditions, sawlogs suitable for milling with simple equipment to provide sawnwood for local joinery and furniture could be produced in about 10 years. Suitable equipment is comparatively low in cost, cheap to maintain and requires a low level of skills and could function at the community level. Appendix 5 gives details of the type of equipment which could be used under these conditions.
Pulpwood
A pulp project based solely on rural community plantations is unlikely, but a pulpmill obtaining part of its intake from large-scale industrial plantations and part from rural community plantations may be an attractive proposition for both sides. A good example is the PICOP project in Mindanao, Philippines, using Albizia falcataria. On the one hand high quality nursery stock and advice on technical matters such as spacing and pruning can be made available by foresters of the industrial forestry enterprise. On the other the production from the rural community plantations can contribute a significant proportion of the pulpmill intake without an equivalent input in labour, management, etc., from the enterprise. Such a symbiotic arrangement confers mutual advantages and should be encouraged wherever the conditions are suitable.
Multipurpose species
The benefits which multipurpose species can bring to communities have already been discussed on page 38. Further examples are given in Appendix 3, particularly in section III.
Environmental Considerations
Shelterbelts
To be successful in shelterbelts, trees must have the following specifications:
Adaptability: the environment of arid regions in need of shelterbelts will generally test the hardiest of species. Trees with the ability to withstand persistent winds, drought and extreme temperatures must be used.Growth rate: this is expressed in terms of the rate and uniformity of height growth. Height is important because it determines the size of the area protected. The taller the tree the greater is the area protected and the minimum the area occupied by the shelterbelt.
Crown formation: characteristics of crown such as height, width, length, shape and density determine the effectiveness of the shelterbelt. Trees with dense foliage from top to bottom, good live branch retention, uniform and dense crown should be used. Sometimes a combination of species that provide a uniform vertical density for the shelterbelt can be used (eucalypts and acacia for instance).
Sand dune fixation
Trees for dune fixation must meet two major requirements. First and most important they must be adapted to the macro and the micro environment of the site. In general this means that in addition to their adaptation to the macro climate, they can be established and grown well on the various catenary variations of the dune sites, wherever possible species used for dune fixation should be capable of producing firewood, poles and posts and perhaps even timber.
Trees that have been successfully used for dune fixation in arid areas are Acacia spp (A. cyanophylla, A. cyclopis), Pinus spp (especially P. pinea, P. halipluris, P. maritima), Casuarina spp (C. equisetifolia, C. cunninghamiana), Haloxylon aphyllum and H. ammodendron, Calligonum spp, Eucalyptus gomphocephala in combination with Acacia cyanophylla.
Watershed management, protection and rehabilitation
The following general criteria would be applicable in most cases for the choice of species, when watershed protection is the primary objective, the direct economic return being a subsidiary goal (FAO, in press (I)):
- good survival and fast growth on impoverished sites;- ability to produce a large amount of litter;
- strong and wide-spreading root system with numerous fibrous roots (In landslide zones deep roots are usually essential);
- ease of establishment and need for little maintenance (The ability to establish readily from vegetative material is an advantage);
- capacity to form a dense crown and to retain foliage all the year round, or at least during the rainy season(s);
- resistance to insects, disease and browsing by game, stock and smaller animals;
- soil improvement, such as nitrification by legumes;
- provision of an economic return.
The logical starting point is to consider the local species. Suitable species should be examined from the natural vegetation, looking into the temporary successional stages, rather than those of climax vegetation, since pioneer species are better adapted to exposure and harsh sites. Some sites may be too severely degraded to support a tree cover, without preparatory treatment. This might consist of the introduction of a pioneer species (which may be a herbaceous species), or by subsoiling, discing, ploughing, terracing, infiltration trenches, ‘gradoni’, check dams for gully stabilization, contour wattling and Staking. In some areas trees should not be planted at all where preparatory site treatment would be too costly to be justified, or on areas where regeneration of the natural vegetation would secure the same protective function. There are areas where trees would be inefficient or even harmful such as very steep slopes subject to slippage or slopes that may be subject to deep landslides. Tree root systems would not be able to provide anchorage, and the increased weight of the tree mass could induce solifluxion.
The establishment of mixed plantations of two or more species allows for a better use of the site if both deep and shallow rooted species are planted and if shade tolerant species are established under light demanding species. Interplanting of cover crops between the trees may also be considered. Where tree species that produce little litter are chosen, the inducement and management of a well-developed understory may be necessary for effective erosion control. The main goal, protection, is not in conflict with the possibility of obtaining a direct economic return from the plantation, except in very steep or very erodable soils. This possibility of a multipurpose use of the watershed is illustrated by the Rio Blanco watershed, which secures the water-supply of the city of Manizales, in Colombia. The watershed has been treated with a combination of Alnus jorullensis and Pennisetum clandestinum (kikuyu grass) at 2 200 m altitude. Nitrogen fixation by the roots of the alder enhances sufficient grass growth for the grazing of three calves per hectare. Telephone poles are obtained from the alders at 12 years of age. Similar successful combinations of Albizia falcataria and Pennisetum purpureum (elephant grass) are reported in nutrient-deficient latosols in Indonesia.
Riverbank and roadside protection
Because of the diversity of situations that may be faced in practice, general criteria cannot be used for the choice of species for the stabilization of river banks, channel banks and road cuts and fills. The only common requirement is a very strong, dense and widespread root system capable of building a natural defense that will resist scouring, undercutting and overland flow, in the case of riparian plantations, and that will hold in steep slopes and unsteady cuts and fills in the case of roadside stabilization.
Except in arid and semiarid zones, where pheatophytes are undesirable because of reduction in water-yield, riparian vegetation should be encouraged as long as it does not impede the normal flow. Plantations may be introduced over the seasonal variation level (extraordinary flood strip of the riverbed).
Species of Eucalyptus, Alnus and Populus are frequently planted in riparian zones, with very high yields, due to the permanent access of the roots to the water table.
For the stabilization of river levees and dikes, and for riverbank protection, cuttings of species of Salix, Alnus and Populus are frequently used, often combined with the physical stabilization of plants by shoring and groins. Bamboo and sago palm are other species which provide a compact rooting system which resists the undercutting action of water and prevents collapse of the bank due to rapid soil moisture variations and changes in the water level.
For the stabilization of road fills, shrubs and herbaceous vegetation are more adequate, although small trees such as Robinia pseudoacacia are also very effective. The planting of slopes in cuts and fills is combined with mechanical treatment, including mulching, in order to secure soil stability for the establishment of vegetation cover.
Wildlife and fisheries habitat
Wildlife, particularly mammalian forms that contribute significantly to the diet of rural communities in forested areas, is generally more varied and prolific where habitats are varied. Thus management of forests that ensures a series of stages of the vegetation is particularly appropriate and produces conditions that provide food and shelter, the basic requirements of all wildlife species.
In many tropical areas, secondary growth of vegetation following timber harvesting or shifting agricultural practices is especially attractive to certain mammal and bird species. Indeed the distribution of some is virtually confined to areas where they have access to such disturbed conditions. Fire also contributes in this respect and can be a powerful tool in the manipulation of habitat for optimal wildlife productivity.
Fish are of course dependent on the presence of aquatic habitats that in forested areas usually take the form of rivers, pools and swamps. The rise and fall of water levels with the seasons are important to the life cycle of fish in tropical waters.
