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5. Comparison of primary sources

The characteristics of the primary sources included in i-WESTAT differ considerably from one another in terms of parameters, geographic coverage, temporal coverage and reference sources, aspects that are described in detail in Appendixes 5 to 10. Given these peculiarities, it is difficult to compare the various sources over a large number of countries.

Sources that provide relatively large comparable datasets are FAOSTAT (2003) and IEA (2002). Figure 2 shows the summary of fuelwood, charcoal and black liquor for the countries covered by both sources (85, 61 and 17, respectively). According to the global FAOSTAT data the common areas include some 81 percent of the entire fuelwood consumption, 73 percent of that of charcoal and 86 percent of that of black liquor.

Consumption of fuelwood, charcoal and black liquor according to IEA and FAO statistics

The differences between FAOSTAT (2003) and IEA (2002) are considerable for fuelwood, where IEA estimates are higher, and for black liquor, where they are lower, while for charcoal consumption they are in reasonable agreement.

The differences for fuelwood are probably a result of the distinct character of the respective data sources. FAOSTAT relies prevalently on forestry statistics, which often underestimate the amount of fuelwood produced (and consumed) in the countries while IEA relies mainly on energy statistics, which may, according to some analysts, be slightly overestimated. Most of the discrepancy between FAOSTAT and IEA estimates of fuelwood consumption originates from the respective estimates for China and India, as shown in the figure 3. Resolving the huge discrepancies for these two countries should be of the highest priority for FAOSTAT and IEA.

With regards black liquor, the difference may depend primarily on the conversion factors applied in deriving the amount of black liquor from paper pulp statistics. This particular aspect requires further investigation and could possibly be resolved by defining and adopting standard conversion factors.

5.1 Definition of best references

As discussed in the section on WETT99 best estimates, most of the references that were identified only a few years ago (1997–2000) as most reliable are no longer valid.

This is a positive sign since it shows improvements in wood energy statistics. In only a few years almost all concerned international agencies have modified their estimation approaches, expanded the geographic coverage and improved on item definitions.

On the other hand, no single reliable source can be identified, which means that the definition of new “best estimates” requires thorough review and cross-referencing of all data sources country by country and item by item. This is a process in which i-WESTAT can demonstrate very clearly its power and usefulness as an analytical tool.

5.2 Contrasting forestry and energy perspectives

The diverging perspectives from the forestry and energy agencies with respect to wood energy, aggravated by the fact that it is considered marginal by both, are often responsible for the critical discrepancies in estimates and the associated confusion.

This contrast can only be resolved by integrating the two perspectives into a uniform analytical context in order to cross-reference and reconcile forestry and energy information and develop a consistent inter-sectoral perspective.

Significant cases are those of Slovenia and Peru, are briefly discussed below.


The Statistical Office of Slovenia produced statistics on fuelwood production (source of FAOSTAT), and on the country’s energy balance (source of IEA) that contrast with each other, as shown in Figure 3. The primary sources and respective references are listed in Table 12.

The FAO/Government of Slovenia Project TCP/SVN/2901 "Supply and Utilization of Bioenergy to Promote Sustainable Forest Management" analyzed all relevant information, including the rich forestry and new census data, applying the Woodfuel Integrated Supply/Demand Overview Mapping (WISDOM) methodology. This process enabled a more realistic level of fuelwood consumption to be estimated in the country, which seems to be better represented by energy data and rather grossly underestimated by forest product data.

Estimation of fuelwood consumption in Slovenia from various sources

I-WESTAT sources of fuelwood consumption estimates in Slovenia

Source name


Country report

Slovenia Wood Energy Statistics (SWSTAT), 2004. Output of FAO/Government of Slovenia Project TCP/SVN/2901 "Supply and Utilization of Bioenergy to Promote Sustainable Forest Management"

FAOSTAT (2003)

Official figure. Statistical Office of Slovenia; forest products statistics

GFPOS 1970–2030

Household Fuelwood model: regional; non-hh Fw model: continental

IEA (2002)

UNECE Energy questionnaires 1993 to 2002. (Correspond to the values reported by the Statistical Office of Slovenia (energy balance) and by Eurostat)

WETT99 best estimate

Refer to Faostat figures available in 1999


The Peru dataset provides another clear example of the diverse forestry and energy estimation perspectives. In his country report (FAO Project GCP/RLA 133/EC), Rocío Malleux highlighted the different consumption scenarios provided by the forestry and energy information sources:

In presenting both datasets, Malleux commented:

“in the case of INRENA, the recording of fuelwood consumption is carried out on a minimal part of the wood actually commercialized for this purpose …” (that may induce an underestimation of fuelwood consumption); and

“the Ministry of Energy and Mines has a permanent monitoring program of energy consumption, by source and by sector of utilization, based on surveys of industries and households especially in urban areas, a factor that might determine an overestimation of fuelwood consumption.”

The Peru dataset is extremely complex, with each source, listed in Table 13, giving different estimations at different times and all totally distinct, as can be seen from the grey data sets in Figure 4. As a result, in spite of so many statistics, no one can accurately estimate the consumption of fuelwood and charcoal in the country. The recommendations by Malleux to improve and standardize data collection methods and to coordinate institutional efforts in this field are highly justified.

Figure 4
Estimation of fuelwood consumption in Peru from various sources.

I-WESTAT sources of fuelwood consumption estimates in Peru


Primary source



Country Report

Country report by Rocío Malleux. Estimates based on forestry statistics and projections (after 1999) from Instituto Nacional de Recursos Naturales – INRENA – Perú Forestal en Números, 1990-1999


Country report

Country report by Rocío Malleux. Estimates based on energy statistics from Ministerio de Energía y Minas (MEM) Balance Nacional de Energía 1998


FAOSTAT (2003)

Official figure (source not known)


FAOSTAT (1998)

Data from INRENA


FAOSTAT (2003)

FAO estimate (apparently GFPOS FAOSTAT model results forced along the official figures series)



Estimates from Fundación Bariloche 1980,1985,1990


GFPOS 1970-2030

GFPOS "Faostat 3 " model based on Faostat 1999 figures (whose reference source was INRENA)


IEA (2002)

Balance Nacional de Energía 1971–2002 communicated to the Secretariat from MEM.


OLADE 90–02


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