- Overview
The consistency analysis model calculates, by country, demand for roundwood (“derived removals”), on the basis of the scenarios for consumption, trade and production of forest products presented in the earlier chapters of ETTS V, using input/output conversion factors available to FAO/ECE. Flows of waste paper and of residues, as well as use of wood for energy are calculated explicitly. This derived demand for roundwood is compared to national forecasts of roundwood supply. In the few cases where the gap between the two in the initial run was unacceptably large, adjustments were made in consultation with national correspondents, so that in the base scenarios, the “gap” between derived and forecast removals is quite small.
The only difference in assumptions between the two base scenarios (BASE LOW and BASE HIGH) is that referring to the speed of growth of the overall economy, as set out in chapter 3.
Although the model is expressed in purely physical terms, it has a foundation of economic theory. All the separate parts of the base scenario assume constant real prices for roundwood and for all forest products.
- Main characteristics
The consistency analysis model is a detailed material balance model, with data by country for four periods: base year around 1990, 2000, 2010 and 2020. All data are in material terms (m3 or tons), but there is a common price assumption for those parts of the base scenario obtained by econometric methods, that prices remain constant. The model is not self regulating, as it identifies and quantifies inconsistencies, but does not resolve them. In order to achieve consistency, it is necessary to reexamine the scenarios, in the light of the inconsistencies, and make any necessary adjustments. It is thus an iterative process and well suited to discussion of scenarios, as it is fairly transparent and requires expert judgement. It is also comprehensive (from the forest to consumption and recovery of forest products) and rigorous, forcing users to take all aspects into account, and not be content with the outlook for only one or a few parameters.
- Input data
The following are the data provided to the model from other parts of the study:
national forecasts of roundwood removals, by species group and size (see chapter 4 and Working Paper by Pajuoja, ECE/TIM/DP/4)
econometric projections of production and consumption of forest products in market economies (chapter 6 and Working Papers by Baudin and Brooks, ECE/TIM/DP/5 and 6)
expert estimates of production and consumption of forest products in the transition countries, (chapter 10 and Working paper by Eronen, ECE/TIM/DP/8)
secretariat estimates of production and consumption of forest products for the smallest countries
net trade in products, which is by definition the difference between consumption and production;
net trade in wood raw material (logs, pulpwood, residues and chips), which is assumed at the initial phase to remain constant at the level of the base year, but may be adjusted at a later stage (see below);
national forecasts of consumption of fuelwood (chapter 8)
rough estimates of consumption of pitprops and other industrial wood;
recovery rate of waste paper (chapter 7);
estimate of the share of available residues which will be used as raw material (chapter 7);
input/output conversion factors (i.e. volume of raw material needed to produce one unit of product), which are assumed to stay constant at the levels reported to the most recent ECE/FAO enquiry1;
share of domestic pulp in pulp consumption (assumed in the initial scenario to stay constant).
- Calculation of derived removals
“Derived removals” are generated from the input data as follows:
consumption of logs for sawnwood and plywood is calculated by applying the conversion factors to the production data;
derived removals of logs are consumption of logs plus/minus net trade in logs;
“availability” of residues (i.e. the amount of residues generated by a given level of production) is production of sawnwood and plywood multiplied by the conversion factor2;
supply of residues is availability of residues multiplied by the estimated share of availability used as raw material, based on 1990 data, and the trends presented in chapter 7;
derived demand for fuelwood and pitprops and OIW removals is consumption of these assortments, plus/minus net trade;
volume of waste paper recovered is consumption of paper and paperboard multiplied by the recovery rate;
volume of waste paper consumed is volume of waste paper recovered plus/minus net trade in waste paper;
consumption of paper making fibres (i.e. pulp plus waste paper) is production of paper and paperboard multiplied by an empirical conversion factor reflecting furnish mix, (notably relative importance of non-fibre raw materials, such as clay fillers etc.) in 1990: the conversion factor (fibre input/paper production) is assumed to remain constant;
consumption of pulp is consumption of paper making fibres, minus consumption of waste paper;
production of pulp is the consumption of pulp multiplied by the share of domestic pulp in pulp consumption;
consumption of total pulpwood for pulp is production of pulp multiplied by an empirical conversion factor, based on the mix of pulp types in 1990;
consumption of total pulpwood for particle board and fibreboard is production of these products, multiplied by the conversion factor.
total pulpwood consumption (all assortments) is the sum of consumption for pulp, particle board and fibreboard;
consumption of round pulpwood is consumption of total pulpwood minus consumption of residues;
derived removals of round pulpwood are consumption of round pulpwood plus/minus net trade;
derived removals of smallwood are the sum of derived removals of round pulpwood, fuelwood, pitprops and OIW;
derived removals of domestic wood are the sum of derived removals of logs and of smallwood.
- Calibration
“Derived removals” were also calculated for the base year and compared to the recorded removals for that period. The main causes for the difference between the derived removals and the recorded data are:
unrecorded removals (autoconsumption of fuelwood etc);
wrong classification of removals into logs or smallwood;
inaccurate conversion factors.
The difference between derived and recorded removals measured for the base year has been used to adjust the projections to prevent any break in comparability over time.
- Adjustment
After an initial run of the base scenarios, each country's data was examined to ensure that the difference between derived and forecast removals was not unreasonably large and that the scenarios passed the general test of “reasonableness”. In the relatively few cases where this “gap” was unacceptably large, the scenarios were adjusted by the secretariat in consultation with the national correspondent. Although any part of the scenario can be adjusted, it was preferred not to change those scenarios which are based on the most detailed and explicit reasoning. For this reason, the secretariat was extremely reluctant to change either the econometric projections or the national removals forecasts. The adjustments were as follows:
in the great majority of cases, it was sufficient to adjust (upward or downward) the figures for net trade in wood raw material, which were based on the initial assumption of “no change”, to achieve base scenarios which were internally consistent.
in Germany, the distortion in roundwood trade due to the huge windblow of 1990 was removed.
no changes were made to any conversion factors (raw material/product or fibre input/paper production), as there is no reliable indication of the direction in which they might move3.
in one country (France), the market share of domestic pulp was increased, as it is clear that in that country, a new resource is coming on stream, which is likely to lead to the expansion of pulp capacity.
finally, in view of the econometric results, and the scenarios for importing countries, the national scenarios for removals by the main European exporters, Finland and Sweden, were raised, after consultation with those countries' national correspondents, and still remaining well within the levels of sustainable wood supply.
It should be noted that for the study itself, the figures given in the earlier chapters are the adjusted data, rather than the original forecast or projections (which are shown in the relevant Working Paper), as it was not acceptable to have different figures for the same parameter in different chapters of the same study.
- Presentation of results
The aggregated results of each scenario are shown on a single sheet per country, at a product group level (although the calculations were done at the level of individual products). This sheet shows consumption, production, net trade, waste paper and residues recovered (used), the derived removals, the forecast removals and the difference between them, as well as a number of ratios (self sufficiency and increment/removals), which serve both as an illustration of trends and a check. This sheet provides a simple yet complete overview of the scenario. They are also aggregated by country group and at the European level.
3 For a discussion of the factors which influence these conversion factors, see ECE/TIM/55.
