3.1 Forest resources parameters
3.2 Projection parameters
3.3 The supply projection
The proposed definitions are consistent with the definition used in the FAO Global Fibre Supply Study (GFSS). Country forest resources figures are those of 1990. Production parameters are put all together in Table 8.
The areas (in ha):
· Total country land: total country land area excluding inland water. Figures are provided from FRA - 90 (Global synthesis - FAO Forestry Paper No. 124) and the FAO Yearbook of Forest Products.· Forest and other wooded lands (FOWL): include all types of forested areas being forests or wooded lands (see definition below). Figures are standardized and taken from FRA-90 (Global synthesis - no 124) and considered as a point of reference for all countries. FOWL are formed of:
· Forests: are ecological systems with a minimum crown coverage of land surface (here assumed as 10%) 1 and generally associated with wild flora, fauna and natural soil conditions. It is worthwhile pointing out that the definition used in the study has a minimum vegetation cover requirement and is often quite different from a legal definition of forest (such as in a Forest Act or Ordinance).1 FAO - Forest Resources Assessment - guidelines for Assessment 1990.· Wooded lands: include forest fallow and shrubs. Forest fallow refers to all complexes of woody vegetation deriving from the clearing of natural forest for shifting cultivation. Forest fallow is an intermediate class between forest and non forest land uses. Shrubs refer to vegetation types where the dominant woody elements are shrubs with more than 50 cm and less than 5 meters height on maturity.
· Natural exploitable forests: refer to natural or semi-natural forests composed of tree species known to be indigenous to the area. It includes bamboo forests. Natural exploitable forest (or commercial forests) means productive and economically accessible forests. It is the area available for timber wood supply. Forest areas having economic restrictions (environmental, health, access constraints) or legally protected (and having significant impact on wood supply) are not included. Figures are often based on information provided by Master plans, articles or documents from national forestry administrations or ministries and are in accordance with GFSS data.
· Plantation forests (or man-made forests): are forests established by afforestation or reforestation. Plantation forests include all types of forest tree plantations whether industrial, communal or individual covering at least an area of about half hectare. Trees on road side, canal banks and homesteads are not included; also rubber, coconut and oil-palm are excluded.
· Low productive/open forest areas: are all forests being considered as poorly stocked or partially exploited. This category of forests includes open forests, totally or partially protected forests and forested conservation areas. Protected forests of watersheds are included. That area is calculated and is the result of the difference between the total forest and wooded land and the natural exploitable forests plus plantation forests.
· Conservation areas: consist of national parks, reserves and protected natural areas which fall under IUCN categories. Figures are provided by the World Conservation Monitoring Centre (WCMC) 2. As it is presently not yet possible to separate forest areas from barren and other lands inside conservation areas, conservation figures are given for information. Conservation areas are included in the low productive/open forests areas and have no immediate implication on total forest area calculation.
2 See document APFSOS/WP/04 prepared by WCMC for this outlook study.· Arable lands: refers to arable land under temporary crops, homestead gardens (agro and urban forestry), and land temporarily fallow or lying idle (recent slash and burned areas). Range lands are not included in arable lands as it is assumed that range lands provide no or very limited wood supply. Arable lands may include trees on roads side and canal banks.
· Commercial tree crop lands: refers to land cultivated with tree crops that occupy the land for long periods. Commercial crop area is mainly related to rubber and coconut plantations that have an significant impact on wood production in some countries.
· Other/range/barren lands: are areas that do not contribute to wood supply. That means barren lands such as rocky lands and deserts. Range lands are included. Area figure is obtained by deducting forest and arable lands from the total land area.
Commercial Growing Stock (CGS)
The Commercial Growing Stock (CGS) means the volume that may actually be cut and removed from the natural exploitable forests and plantations forests. This volume of wood may include wood for industrial purposes (e.g. sawlogs, veneer logs, etc.) and for local domestic use (poles for construction). Use of wood for fuelwood is not included in this category.
· CGS natural forest (in m3/ha): is the estimated over bark volume of all actually commercialised trees (over 10 cm diameter at breast height) living on one hectare in the natural exploitable forests. In tropical forests, only a small part of the total growing stock can be effectively used for commercial purposes. Figures on commercial growing stock in natural exploitable forests are often estimated or extrapolated from similar situations.· CGS plantations (in m3/ha): is the estimated over bark volume of all trees (over 10 cm at breast height) growing on one hectare of tree plantation. As almost no average figures exist (except for some countries, but to what extent are they valid?), the commercial growing stock is difficult to appraise as plantations are a mix of mature and young (in majority) stands with the age distribution not known.
Mean Annual Increment (MAI)
The MAI (Mean Annual Increment) is the volume of wood growing on one hectare of forest during one year (m3/ha/year) on average since the forest has been established. For a tree plantation, the MAI is the present total growing stock volume of one hectare divided by the total age. The total age of the natural forest is not known. In this study, MAI is related to the CGS.
· MAI natural exploitable forests (m3/ha/year): is the mean annual increment (per ha) of the commercial species growing stock in natural and semi-natural forests. Generally no precise figures are available, only guesstimates exist. Recent studies show that MAI of natural exploitable forest is very low and sometimes negative due to natural death. Figures used fall between 0 to 2 m3/ha/year.· MAI plantations (m3/ha/year): is the mean annual increment (per ha) of forest plantations. Good estimates exist in various situations. Plantations may include fast growing trees as well as low growing trees. Used figures are in the range 2-18 m3/ha/year depending on species, age and reported growth.
· MAI other forests (m3/ha/year): is the mean annual increment (per ha) of wood stock growing in all forests areas which are not classified as production forests such as low productive, protected and open forests. Figures are guesstimates. However, it is certain that large areas of low productive/open forests produce significant amounts of fuelwood and other products. A coefficient ranging from 0 to 1.5 m3/ha/year is used at least to show that these areas have some production potential which has to be taken into account.
· MAI commercial crop plantation (m3/ha/year): is the mean annual increment (per ha) of wood produced mainly from rubber and coconuts plantations. Good estimates exist in some countries. These estimates have been extrapolated and proposed figures range from 0 to 3.5 m3/ha/year.
· MAI arable lands (m3/ha/year): is the mean annual increment (per ha) of wood stock produced from agricultural lands including homestead production. Homestead production has been studied in various situations although national average figures are not precise. Average production is proposed between 1 and 2 m3/ha/year.
Fellings
Felling is the volume felled during a given period whether or not removed from forest or other felling sites; that includes silvicultural and pre-commercial thinnings and cleaning left in the forest. Normally volume is over bark. Removal is only what is exported from the forest and corresponds to fellings less harvesting residues.
· Industrial roundwood (m3/year): include all industrial wood in the rough (logs, sawlogs and veneerlogs, pulpwood and chips, poles, piling, pitprops, match blocks, etc...) but no fuelwood. Official figures are generally available.· Waste and residues (%): represents the felling residuals which are left in the forest after felling and not salvaged. This is a coefficient (%) attached to the industrial roundwood supply and should give the quantity of wood wasted during the harvesting operations. This coefficient varies according to the quality of forest logging and management methods. The coefficient may vary from 10 to 50%.
· Fuel and other wood consumption (m3/inh/year): is the wood in the rough to be used as fuel for cooking, heating and energy production. Other wood includes a certain amount of local timber (poles, piling and posts) which is not recorded in the formal sector but is used by farmers and rural communities. Figures are based on the population's consumption estimate (per inhabitant).
Population
· Population (inh): the total inhabitants living in the country in 1990. Estimations are from the UN document - "World Population prospects: the 1994 revision". The medium variant has been used.· Population increase (% per year): is the annual increment (in percentage) of the country population. Estimates and forecasts up to the year 2010 are taken from FRA - 90 or from UN - "World Population prospects: the 1994 revision" in the median variant tables.
The likely development of forest resources and wood supply by 2010 is shown by five year period. It is based on the following parameters or assumptions:
· deforestation factor (%): is the annual deforestation percentage on FOWL provided by FRA 90 and related to the country. It applies to natural exploitable forests and to low productive/open forests and is constant for the whole period. The deforestation factor varies from 0 to 2.5% per year. Assumption is made that deforested lands are turned into arable land (keeping some potential for wood production) and rangelands (see range conversion factor).· Plantation forests programme (ha per year): is a prevision for the annual planting programme for man-made forests. Estimates are based on the country planning objectives and the country capacity to realise the programme. The prevision is constant for the whole period except for some specific cases where prevision is done by five year period.
· removals - industrial roundwood (in m3/year): is an annual estimate of the domestic industrial roundwood supply. Figures are generally from country official sources. A constant waste and residues coefficient is applied to get fellings estimates.
· conservation area (in ha): shows the possible increase of the total protected areas.
· commercial tree crops (in ha): gives the possible evolution of the area under rubber, coconut crops which could produce wood as raw material.
· Range lands conversion factor (%) is the estimated percentage of deforested lands converted into cultivated lands. Deforested lands are not always turned into arable and cultivated lands but part of them are turned into rang and barren lands. Assumption is made that range lands do not produce significant amount of wood.
· other/range/barren lands area (in ha): shows the increase of area of the non wood producing land area under the assumed percentage of range conversion factor.
Formulas
The column 1990 uses the forest resources parameters when applicable. For each five year period, the following formulas have been applied:
Production forests
Area total = natural exploitable forests + plantation forests
· Natural exploitable forests = exploit. for. - 5 years x (exploit. for. x deforestation factor).· Tree plantations = tree plantations + 5 years x annual tree planting programme.
Commercial Growing stock (CGS)
a) for 1990 = baseline information = CGS nat. exploit. forest + CGS plantation forests.b) For 1991 - to date = CGS nat. exploit. forests + CGS plantation forests + 5 years x (SI total - fellings total) of the preceding period.
· Nat. exploit. forests = nat. exploit. forest area x CGS/ha for nat. exploit. forest.
· Plantation forests
a) for 1990 = baseline information = plantation forests area x CGS/ha plantation forestb) for 1991 - to date = CGS of the former period + 5 years stock increase (plantation forest area x MAI/ha/year).
Annual wood Stock Increment (SI), {Total SI = SI natural forest + SI plantations}.
· SI - Natural exploitable forest = nat. exploit. forest area x MAI natural exploitable forest.
· SI - Plantations = plantation forests areas x MAI plantation forests.
Fellings industrial roundwood, total = ind. roundwood removals + waste and residues.
· Industrial roundwood removals = see projection parameters.
· Waste and residues = industrial roundwood removals x percentage of waste and residues.
Other forests and wooded lands
Conservation areas = see scenario parameters
Low productive/open forests = low prod./open forests area - 5 years x (low prod./open for. x deforestation factor).
Wood stock increment (SI), total = low productive/open forests area x MAI (other forests).
Non forest lands
Commercial tree crop lands = see scenario parameter.
Arable lands = total country land - total forest and wooded lands - other/range/barren lands - commercial tree crops lands.
Wood stock increment (SI), total = commercial tree crops lands area x MAI (commercial tree crops) + arable lands area x MAI (arable lands).
Fellings fuelwood, total = fuelwood consumption per inhabitant x country population + 5 years x (total fuelwood consumption x percentage annual population increase).
Results
- Wood Stock Increment (SI), all sources: is the Total Annual Increment of wood produced from all productive areas: production forests, other forests and wooded lands and non forest lands.
= SI production forests + SI other forests and wooded lands + SI non forests lands.
- Felling, all sources: is the total volume of all trees that are felled either for industrial or fuelwood purposes.
= industrial roundwood fellings + fuelwood fellings.
- Total forest and wooded lands: is the evolution of the total forested area taking into account deforestation effects and plantations programmes.
= total production forests area + low productive/open forests.
- Percentage of total land: gives the possible evolution of the proportion of land covered with forests and wooded lands.
= total forests and wooded lands area/total land area x 100.
