equivalent volume "RWE volume"
As such, it is particularly useful when assessing trends in the forest footprint of a given country's production, imports, exports and end-user consumption of wood-based products. For example, it is quite wrong to imply that China has a trade deficit in all species and qualities of timber - although (during 2006) the volume of timber products which China imported exceeded (by a substantial margin) that which China exported, the RWE volume of timber which China exported exceeded that which it imported.
Such assessments depend partly on the reliability and comprehensiveness of published statistics (see Footnotes 1 & 2 below) - and partly on the reliability of the factors which one adopts when estimating RWE volume from wood volume or product weight.
Analysis of world trade in wood-based products would benefit from consistency and standardisation concerning which factors to adopt for each group of products - whether as global averages or for each producer country/region (so as to, for example, reflect particular forest types).
The more discussion there is concerning these factors (and data quality) the more likely it is that policy will improve and that policy makers will have benchmarks by which to judge progress in monitoring trade - and more particularly, in combating trade in Illegal Timber.
Readers of this webpage are urged to forward their comments to email@example.com with a view both to refining how RWE volume is estimated and to increasing the use of RWE volume as a tool to help monitor bilateral and global trade in wood-based products.
Several countries do not bother to publish trade statistics from which one can directly determine the physical quantity of the wood-based products which is being traded. Ideally, weight should be reported for all trade flows. Where appropriate, statistics should also be reported for other units of physical weight, primarily either volume or both thickness and surface area. One can however derive applicable unit values from similar trade flows which are reported (see Footnote 3). Weight (not number of items) should be the primary unit of measure other than import or export value for statistics of trade in wooden furniture.
RWE volume does not reflect the reduction in standing volume of trees which is attributable to the felling and extraction of logs. Neither does it reflect the impact of that extraction on the forest ecosystem.
Sector (see Footnote 4 below):
A factor of 1.0 would be appropriate for, say, sawn wood if the saw dust and off-cuts generated in a saw mill is used as wood raw material in the subsequent manufacture of pulp or wood-based panels - provided of course that one needs to avoid double counting, as when estimating actual consumption of wood raw material.
In contrast, one should ignore the actual source of the wood raw material when estimating the RWE volume of a given quantity of a given product. Factors such as those introduced below would be appropriate for such analysis.
Unless credible alternatives are available, the factors (and densities) used by the ITTO, UCBD and UNECE should be adopted when assessing timber imports from most High Risk countries (countries whose exports of wood-based products are particularly likely to include Illegal Timber - i.e. tropical producer countries almost all of which are ITTO members, China and Russia). Of course, other factors are required for products not covered by those suggested by these three organisations.
A set of factors has been proposed [OECD Table A3] for such timber products as furniture, joinery, ornaments, picture frames, and tools which account for most of the increase in import value of trade from High Risk countries during recent years, and which (due particularly to China's very large and rapidly increasing exports of Illegal Timber) comprise a substantial proportion of the RWE volume of global trade. High Risk countries are defined here as countries whose wood-based product exports are likely to comprise a substantial proportion of Illegal Timber. However, the factor of 3 used in that study might be too large - 2.5 might be more suitable, particularly for doors and parquet.
Products (including some furniture, picture frames, engineered flooring, fibreboard, etc) made primarily from plantation species and particularly ruberwood should be excluded from analyses of trade in tropical timber (i.e. timber from natural forest and plantations such as those of teak in Indonesia). However, they should be included in analyses of the quantity of trade in wood-based products.
The smaller the size of components for timber products (for example strips for parquet and sawn wood for chairs) the less wastage their might be from the wood raw material (often of standard dimensions) out of which they are made. Careful jointing can of course help minimise waste.
Importing country statistics are useful in estimating the exports of countries whose trade statistics are not readily available and vice versa. However, one must assume that the quantity imported equals that exported - except of course for statistics of value. Depending on product, the ratio between import value (cif) and export value (fob) - when measured per unit of weight or volume - should exceed 100%. Unexpectedly large cif/fob ratios might indicate transfer pricing fraud.
The ITTO [Slide 14] and European Hardwood Federation (UCBD) both seem to use the factors 1.8, 1.9 and 2.3 for sawn wood (HS code 4407), veneer (HS code 4408) and plywood (HS code 4412) respectively - for tropical (and other) timber. However, given that analysis of reports freely available from the Internet indicate that a factor nearer 3 is actually achieved for tropical sawn wood milled in Africa, it is not clear whether the factors used by the ITTO and UCBD are widely applicable. The greater the quality of the mill's output, the greater the conversion factor is likely to be. In contrast, the factors used by some in China differ very greatly from these - for example 1.5 for both sawn wood and plywood [second paragraph page 9, third paragraph page 19, final paragraph page 27] .
The UNECE provides an interesting summary of factors concerning each of the countries which its database covers - including Russia. Individual countries also provide their own summaries, for example Sweden [Sågade trävaror] and the UK [page 2 adjusted as per page 1]. Sweden is cited here as an example primarily because, factors adopted in Scandinavia are unlikely to be lower than applicable to Russia NB for export-oriented products of similar species (on account of differing motivations and mill equipment between the two countries). However, the factors which this UNECE source uses for sawn softwood in Russia are smaller than those cited for Scandinavia - which might imply that the UNECE factors are averages across the domestic and export-oriented market, rather than only the latter.
The UNECE also adopts as standard [ConversionFactors tab] the factors 1.67 for sawn softwood, 1.82 for sawn hardwood, 1.9 for veneer, and 2.3 for plywood. The UNECE Table 220.127.116.11 and Timber Bulletin 50 (3) suggests the factors 1.4 for particle board and 1.8 for fibreboard.
A number of the factors which have been proposed concerning China [footnote 6, e.g. sawn wood] [Annex II, e.g. wood chips, sawn wood, and wood works] and [Cintrafor slide 13, e.g. 3.0 for wood-based panels] might not be applicable to products of a quality sufficient to enter international trade or might be misquoted perhaps as a consequence of misunderstanding or mistranslation. Other sources of questionable factors adopted for China include [Tables 1-2 and 1-3 ] and [p15 - use of this factor might underestimate production of saw logs by at least 30% and might lead to imprudent policies].
For other sources, see [EU Anhang, NB in units of m3RWE/tonne], [Europe Table 1], [Peru Equivalencias usadas], [Tropical footnote 3], [Finland page 88 and pages 12, 20 & 21], [UK page 19], [New Zealand tab 7].
A wide range of factors tends to be cited for tropical sawn wood, for example from 1.8 to more than 3 [Section 8.1].
Other things being equal, the volume of logs needed to make a given product will depend on the diameter of the log - the larger this is, the smaller the quantity of logs needed. Consequently, one might expect that the RWE volume of sawn wood made from tropical timber grown in natural forest would be lower than that of sawn wood made of softwood grown in a plantation. How much of a log is suitable for a given product will depend partly on the log's heartwood and (less durable and less stable) sapwood.
Likewise, conversion factors for small products might be smaller than for larger but otherwise similar products.
The factor(s) applicable for wooden furniture (HS codes 940161, 940169, 940330, 940340, 940350, 940360 and, if codes of more than six digits are available, perhaps one or more or of the HS codes 940190* and 940390*) should exceed those of the materials from which they are made - primarily sawn wood (1.8) or wood-based panels (1.4 to 2.3). One might assume that a factor of 2.0 is appropriate overall. Ideally, for upholstered furniture, the weight of wood is less than the weight of the product (which includes springs, upholstery, etc).
~ Mass (weight) ratios:
One can estimate the factor used by those pulp or paper mills whose owners publish relevant data in environmental or annual reports. The annual reports of national paper industry associations might publish sufficient information to enable one to estimate relevant factors.
The virgin wood fibre content of each type of paper might vary from country to country. Prior to 2008, the price of waste paper rose and availability reduced in many countries - in response to the rapidly increasing quantity which China was importing. The content of fillers such as clay will vary by type of product.
Although one should ideally assign a factor to each type of product imported from each country, doing can be rather time consuming. An attempt to do so has been carried out in respect of China [page 57-58]. It would be much simpler to assume a universal factor such as 3.5 m3 RWE per tonne irrespective of the source or type of paper.
The same approach is more practicable for wood pulp (partly because fewer product groups and countries are usually involved). Adopting a universal factor, such as 4.5 m3 RWE per tonne, is more likely to be robust - particularly if trade is dominated by one type of pulp (usually that of HS code 4703).[page 57]
Assessing the RWE volume of a country's paper exports is particularly challenging if a substantial proportion of this derives from imported pulp and paper - as in the case of China [pages 57-58].
There are fewer High Risk countries in the Paper Sector than in the Timber Sector - primarily China (due both to the establishment of certain major mills and to domestic pulpwood supplies), Indonesia and Russia (but increasing supplies of FSC-certified products are being exported). The exports of Paper Sector products by China and some other countries' (notably within the EU) are of course also at risk from contamination by Illegal Timber (pulpwood, pulp and paper) supplied from Indonesia and, perhaps to a lesser extent, Russia. Whether or not Brazil should be regarded as a High Risk country concerning Paper Sector exports is debatable.
A number of sources (see Footnote 2 below) provide trade statistics which are more comprehensive and more up to date thatn those published by the ITTO.
On of these is UN Comtrade. However, its statistics of physical measure are often fictitious, based on a constant factor of value.
For several products, Eurostat no longer requires that weight is declared for intra-EU trade. This makes it difficult to identify the not infrequent anomalies in Eurostat's volume data. Although the statistics published by Eurostat should be identical to those published by each EU member state, they are not, and judging by the UK's data, Eurostat data is the least reliable of the two.
The USA does not even bother to declare more than value for several high unit value products which account for a significant proportion of trade.
Although the revenue generating role of customs posts is reducing with the elimination of tariffs, the need for customs posts to provide surveillance and reliable statistics of trade is increasing - in parallel with trans-border criminality.
The summer Newsletters of the ATIBT (no longer published) used to include bilateral statistics of timber exports from a number of tropical timber producing countries. The MTC used to publish bilateral statistics of the timber exports of Peninsular Malaysia, Sabah and Sarawak - based on MTIB data (but only for 4-digit HS code groups - statistics for 9-digit HS code groups are available from other sources for the federation as a whole); up-to-date monthly import and export value data are published by the DOS. Ghana publishes its export statistics monthly. Guyana publishes semi-annual summaries of its timber exports.