Collecting and preparing a wood energy database is a complex process due to a number of reasons: diversity in consumption patterns, variation in heat contents in different species of fuelwood, differences in measurement of volume and weight, lack of regular surveys on wood energy supply and consumption, and divergence in the way wood energy data are presented. Because of this wood energy figures are likely to be different in different databases. Thus, when wood energy data are gathered either for national planning and policy purpose or for some analytical studies, confusion sets in regarding the reliability of data and statistics available from different wood energy database or statistics. It is therefore, mandatory, to explore the existing database, evaluate their reliability and consistency and to identify the most appropriate database for above mentioned purposes.

This chapter discusses the existing situation of wood energy database for 16 Asian countries which are also the members of FAO’s Regional Wood Energy Development Programme in Asia (RWEDP). It tries to present an overview of wood energy database at a regional level. There exists only very few databases that includes wood energy figures for Asia. The known wood energy databases on Asia are FAO Forest Products Yearbooks, UN Energy Statistics Yearbooks and CEERD/AIT Energy-Environment Database. At the national level, some countries (e.g., Bangladesh, Myanmar, Nepal, Sri Lanka, Thailand) do have statistics on wood energy.

The word "fuelwood" in this part of the study represents the combination of primary fuelwood and its main derivative� charcoal. Fuelwood from FAO and UN databases corresponds to the fuelwood originated only from the forests (does not include wood wastes or recycled wood), whereas fuelwood from CEERD/AIT databases also includes fuelwood from other sources such as trees in home garden and agricultural land and wood wastes. The main sources of CEERD/AIT database are national statistics, which include these other sources of fuelwood.

1. FAO forest product Yearbook [FAO 1996]
2. UN energy statistics [UN 1996]
3. CEERD/AIT energy and environmental database.

1. Data on wood energy Consumption in physical unit (Table A.z.1)

These tables consist of total wood energy data expressed it terms of volumetric unit (thousand cubic meter). The data for these tables compiled as follows:

FAO Forests Products Yearbook (FAO, 1994) provides domestic production, import and export of fuelwood and charcoal in volumetric unit (thousand cubic meter). Since we need wood energy consumption data, we can not directly copy the production figures as presented in the statistics. Hence, we first calculated wood energy supply data from the following relationships:

Wood energy supply = Domestic production + imports - Exports

With an assumption that there is no transportation and distribution losses of wood energy, wood energy supply equals to wood energy consumption.

In contrast, UN energy statistics presents fuelwood and charcoal consumption data in different units. Fuelwood consumption is presented in cubic meter, while charcoal is presented in tonne. However, domestic production and export of charcoal are already included into the domestic fuelwood production. Imported charcoal is converted into equivalent fuelwood and presented in cubic meter. Hence, total fuelwood consumption is given as:

Fuelwood_total (cubic meter) = Fuelwood (cubic meter) + Imported charcoal (in tonne)/(eff * d)³

where,

eff = Factor converting fuelwood to charcoal or charcoal kiln efficiency; the value taken here is 0.225⁴.

d = Factor converting volume to weight of fuelwood or density of fuelwood on dry basis, the value
      taken here is 0.72⁵.

Only a few Asian countries import charcoal, and the imported amount is very small compared to the domestic production.

In the case of the AIT database, both fuel wood and charcoal are presented in mass unit (thousand tonne). They are converted into volume unit as follows:

Fuelwood_total (cubic meter) = Fuelwood (tonne)/d + imported charcoal (in tonne) )/(eff * d)

where "eff" and "d" have the same values as in the UN statistics.

2. Data on wood energy share in total forest removals (Table A.z.2)

These tables present the share (in percent) of wood energy in total forest removals. Wood energy share in total forests removals represents the ratio between the amount of fuelwood production and total round wood production (both presented in volumetric units) within the country. However, round wood production data is available only in FAO forest products yearbook. Hence, the same data are used for calculating this indicator for the other two databases.

3. Total wood energy consumption in energy unit (Table A.z.3)

Data in these tables are presented in terms of energy unit (peta joule). Conversion factor from volumetric unit to energy unit for different countries and in the cases of different databases are given in Table 2.1.

4. Share of biomass energy consumption in total energy consumption

These tables present the share of biomass energy (in percent) in total energy consumption. However, biomass energy consumption data are not available from the FAO database, so these indicators are not calculated for the FAO database. Total energy consumption data for calculating these indicators in the case of the UN and AIT databases were taken from the respective databases.

5. Share of wood energy consumption in total biomass energy consumption

These tables present the share of wood energy (in percent) in total biomass energy consumption. It represents the ratio of total wood energy consumption to the total biomass energy consumption. However, as the biomass energy consumption data are not available for the FAO database, this indicator has not been calculated for the FAO database.

6. Share of wood energy consumption in total energy consumption

These tables gives the ratio of total wood energy consumption to total energy consumption. The calculation of these indicators for the FAO database uses the total energy consumption figure from UN sources.

Source: UN and AIT.

8. Consumption of wood energy in various sector in energy unit

These tables present wood energy consumption data at the sectoral level in energy unit (peta joule).

Data of FAO statistics are collected by means of questionnaires send to concerned departments of all countries in the world. However, in the absence of official replies of the questionnaires, data are either estimated by FAO or obtained from other sources. The data for all countries under this study are estimated data (not the real data) and are subjected to change in the next issues of FAO Forest Product Yearbook if suggested officially by the governments or new information were available from any other sources. The estimates of fuelwood production data in this statistics based on the per capita fuelwood production and population growth rate.

The definitions of forest products follow the classification and definitions of forest products, FAO, Rome, 1982. However, there is no explicit definitions of fuelwood. This study also follows the definitions of fuelwood as stated in van den Broek (1997). However, Broek (1997) is not clear whether the fuelwood corresponds only for the fuelwood from natural forests or from both natural and on-farm forests (e.g., trees in home garden, agricultural land etc.). This study assumes that fuelwood data from FAO statistics refers to the fuelwood from all types of forests i.e., natural, private, social or community forests. The statistics however, defines charcoal. According to which, charcoal is "wood in the rough (from trunks and branches of trees) to be used as fuel for purposes such as cooking, heating or power production. Wood for charcoal, pit kilns and portable ovens is included." But, it is amazing! this in fact, is the definition of fuelwood not of charcoal.

2.3.2. Energy Statistics Yearbook--the data source for UN wood energy database

Energy Statistics Yearbook is an annual publication of the United Nations, published by Department of Economic and Social Information and Policy Analysis. This statistics presents time series (for the past 4 years) data on production, trade and consumption of various types of energy commodities for the countries all over the world. Since this statistics presents data for past four years and the data of the earlier issues are always revised in the new issues, this study uses various issues of this statistics. For example, Energy Statistics Yearbook, 1983 (published in 1985) which presents data for years 1980-1983, was used for data for year 1980. Similarly subsequent issues were used for the data till 1991. Since the latest available issue is "Energy Statistics Yearbook, 1994 (published in 1996), data for the 1992-1994 period were also taken from this issue.

This statistics includes both conventional and biomass energy commodities. The conventional commodities included in the statistics are coal (hard coal, lignite, coke, peat, hard coal briquettes and lignite and peat briquettes), petroleum (crude petroleum, LPG, aviation gasoline, motor gasoline, kerosene, jet fuels, gas-diesel oils, residual fuel oil), gas (natural gas, other gas) and electricity (hydro, thermal, nuclear). The biomass fuels included in the statistics are fuelwood, charcoal and Bagasse. Data for each type of fuel and aggregate data for the total mix of conventional fuels are provided for individual countries as well as summarized into regional and world tables. There are altogether 38 tables in the statistics, of which Table 13 provides production and trade of biomass energy.

The data in this statistics are compiled primarily from annual questionnaires distributed by the United Nations Statistical Division and supplemented by official national statistical publications. Where the official data are not available or are inconsistent, estimates are made by the Statistical Division based on governmental, professional or conventional materials. Estimates include, but are not limited to, extrapolated data based on partial year information, use of annual trends.

Fuelwood in this statistics is defined as "all wood in the rough used for fuel purpose. Fuelwood production data include the portion used for charcoal production, using a factor of 6 to convert from a weight basis to the volumetric equivalent (metric tons or cubic meters) of charcoal". Similarly, charcoal is defined as "solid residue consisting mainly of carbon obtained by the destructive distillation of wood in the absence of air". Biomass fuel in this statistics refer to fuelwood, charcoal, Bagasse, animal, vegetal and other wastes.

2.3.3. CEERD/AIT Energy-Environment Database

What is the "best" estimate for wood energy use? This is a not a very easy question to answer. However, it is necessary to choose a particular database when making an analysis as mixing data from various databases would not only distort the result but would also give wrong signals to policy makers. Before answering the question on the best estimate for wood energy use, it is necessary to identify the strong and weak points of the three databases described in this study.

• Provides time series on wood energy consumption data for all countries.

• Data are more consistent than the UN and AIT base.

• Data are regularly updated and improved.

• Wood energy consumption data are all estimated for the countries under study. Furthermore, the estimation is based only on population growth, which is not the only driving factor for wood energy demand. (In the long run, income becomes a very important determining factor.)

• Wood energy consumption data refers only to fuelwood supply from forest, and thus do not take into account fuelwood supply from non-forest lands, which can be very significant for at least some countries.

• Data are highly aggregated. For example, wood energy consumption by sector is not available.

• No information is given on total energy consumption; hence, the importance of wood energy cannot be interpreted in terms of its contribution to total energy requirement.

• No definition of "fuelwood" is provided and the definition of "charcoal" is misleading.

2.5.2 UN Database

• Time series on wood energy data for all countries is available.

• It gives the whole picture of energy consumption including both conventional and biomass energy sources. This facilitates analysis of the role of wood energy in meeting total energy requirement from one database.

• The definition of fuelwood is very clear; it includes fuelwood and charcoal.

• Since UN database takes fuelwood energy consumption from FAO statistics for most of the countries and there is no data available for total energy consumption in FAO statistics, these two databases will complement each other for an overall wood energy consumption analysis.

• UN energy statistics uses FAO statistics as its data sources for more than 50% of countries selected under this study. The other half comes from other sources. In this regard, the FAO database provides more consistent set of data.

• Time series data on fuelwood consumption shows "spikes" in some years for a number of countries. No explanation is available for the big discrepancies.

• UN statistics encounters with several topological errors. For example, in the case of Bangladesh, several issues of UN Energy Statistics Yearbook (1981 to 1989 editions) show the total energy consumption (the sum of biomass and conventional energy consumption) either lower than biomass energy consumption or not equal to the sum of biomass and conventional energy consumption⁷.

• The flow of time series on wood energy data is inconsistent in some country cases due to changes in original sources of data. For example, wood energy consumption for Bangladesh dropped five times in 1983, which is very unlikely in reality. It appears due to the change of original source from FAO to national statistics.

• As in the case of FAO database, no disaggregation is available for production by source and for consumption by sector.

• All data (whatever available) were taken from national statistics and hence the data are most probably the real data not the estimated one.

• Wood energy consumption data provide sectoral disaggregation to some extent.

• It provides information on other energy (conventional) consumption; hence the importance of wood energy can be calculated in-terms of total energy requirement.

• Time series data on wood energy are provided only for a very few countries.

From the comparison of various databases in terms of their merits and demerits, it can be concluded that no single wood energy database is favored for analysis purposes. For making regional overview and analysis, the FAO database provides more consistent set of data that are available for all countries covered by the study. On the other hand, the CEERD/AIT database are most useful for making country specific analysis, in particular for countries where a comprehensive set of data exist. The UN database provides time series data on total energy consumption. Otherwise, it is less useful than the other two databases.