1. Introduction
The EU Directive on the Promotion and the Use of Energy from Renewable Sources (RES Directive) mandates that Member States set legally binding targets for increasing the share of renewables in gross final consumption [
1]. The EU target is 20% renewables by 2020. In 2012, the renewable share of energy comprised around 14%, with wood contributing to more than 40% of renewable energy consumption in the EU-27 [
2]. The RES Directive is expected to significantly increase the demand for fuelwood in the EU. However, such a substantial growth in timber consumption has increasingly come under scrutiny for potentially increasing environmental pressures domestically and abroad with harmful effects on e.g., the climate [
3,
4,
5] and biodiversity [
6,
7].
For example, a large-scale strategy to increase bioenergy from forest harvest has been called into question: “This strategy is likely to miss its main objective to reduce GHG emissions because depleted soil fertility requires fertilization that would increase GHG emissions and because deterioration of current biomass pools requires decades to centuries to be paid back by fossil fuel substitution, if paid back at all.” [
3] (p. 5). The authors also argue that forest canopy structure and composition would be simplified, affecting ecosystem diversity, function and habitat (ibid).
Similar findings have been made at the EU level. A report from the Joint Research Centre of the European Commission assessed the current practice of carbon accounting for forest bioenergy. It argues that: “The assumption of biogenic carbon neutrality is not valid under policy relevant time horizons (in particular for dedicated harvest of stemwood for bioenergy only) if carbon stock changes in the forest are not accounted for” [
5] (p. 18). The study recognizes that the classification of ‘carbon neutrality’ increases the attractiveness of using timber for renewable energy generation, and notes that stemwood harvesting for bioenergy purposes is expected to grow in the future. However, it finds that: “The use of stemwood from dedicated harvest for bioenergy would cause an actual increase in GHG emissions compared to those from fossil fuels in the short and medium term (decades), while it may start to generate GHG savings only in the long term (several decades to centuries)” [
5] (p. 16). The study argues that a decrease in emissions due to removal of forest residues, thinning and salvage logging is more achievable in the short term, especially if the counterfactual scenario would be to burn the residues on the roadside. This feedstock is expected to provide most of the additional increment of biomass for bioenergy by 2020 according to that study (ibid).
However, the sustainable potential of forest residues estimated by the literature varies. At a global level more modest, yet realistic, estimates relate to around 4 EJ (Exajoule) to 6 EJ (440 Mm
3 to 660 Mm
3) [
8,
9]. This could cover only around 1% of current global primary energy demand, but would raise total harvest supply volume by around 11% to 16%. However, these values seem relatively high in comparison to the EU, where sustainable residue removal is estimated to increase the supply capacity of EU forests by around 10% [
10,
11,
12,
13], or even only 5% in one scenario with stricter environmental regulations [
14]. Even minor increases in harvesting and removing residues may cause major nutrient losses [
15]. More research is urgently needed on the sustainable potential of residue removal—including stumps and roots [
16,
17]—for different types of forests. It does not, however, seem likely that the level of wood needed to meet renewable energy targets in the EU may be sourced from residues alone. This raises the questions: how should timber be sourced and can it be supplied in a sustainable way?
The European Forest Sector Outlook Study II reaches similar conclusions about the challenges of meeting renewable energy targets with wood [
18]. The study suggests developing a strategy that integrates the needs of the energy sector with that of the forest sector by, e.g., promoting energy efficiency, cascading use, other renewables and non-forest sources of timber. It also suggests to: “Develop fast growing biomass plantations on agricultural land where this is possible [and] if necessary import energy wood (or fuels derived from wood such as pellets or biofuels, which are considerably more energy intensive) from sustainable sources outside Europe” [
18] (p. 81). This raises concerns about the impacts of EU timber consumption in other regions as well as on the growing import dependence of the EU.
Looking at global trends, it is commonly assumed that industrial roundwood will increasingly come from planted forests in the future [
19], and that: “Growth in production from planted forests is expected to keep up with [global] demand growth for industrial roundwood.” [
19] (p. 69). This trend raises concerns about sustainable land use. The concept of sustainable forest management has evolved from exploitive forestry—where the objective of sustainable forest management was to sustain yields—to precision forestry—where the objective of sustainable forest management is closer to integrated natural resource management [
20,
21]. Industrialized, fast-growing plantations are typically managed to only optimize timber productivity. On the one hand, fast-growing plantations need less total area to produce timber, and thus may free-up natural forests for other services [
22], especially if those plantations are established and managed with community interests and landscape uses in mind
1 [
23]. On the other hand, as land competition grows, fast-growing plantations managed exclusively for timber may increasingly compete for land with natural forests managed for multiple services. There is a risk that high yield timber production will gain the upper hand in this competition, because it is more profitable over the short term [
24]. The demand for products from low-quality timber (e.g., pulp and wood-based panels) as well as fuelwood, are also increasing and are well-suited to fast-growing plantations. Through high-tech innovation, such wood fibre can be made into “new” types of products (e.g., including composite woods), changing the structure of the forest industry over the long term [
25]. Demand for high-quality timber from a forest managed for multiple-uses may increase the value of that forest, and raise incentives to manage it in a sustainable way. While too high of a demand may cause overharvesting, too low of a demand may decrease the incentives to manage it in a sustainable way (especially if another kind of land use is more profitable). This points to the need for a combination of production and consumption oriented approaches to promote balance between sustainable forest management and sustainable timber consumption.
It is the level of demand that determines the magnitude of potential impacts. Certification can support sustainable management practices at the forest level but is ineffective against overexploitation caused by high levels of demand. For example, as a “thought experiment”, if a country or territory like the EU were to substitute all fossil fuels used for heating with timber, all else being equal, most would intuitively agree that this would be unsustainable due to the high level of demand (regardless of site certification). Granted, this is an extremely far-fetched “scenario”, but it does raise an important question: how much timber can be consumed under sustainable conditions, now and in the future? This article argues that a sustainable level of timber consumption is characterized by balance between supply (what the forest can provide on a sustainable basis) and demand (how much is used on a per capita basis, considering equity and the concept of “fair shares” [
26,
27]. This is easier to imagine at a local scale, with a visible link or feedback signal between supply and demand (e.g., causing the price to increase as the resource becomes more scarce and/or impacts emerge). Trade removes or delays the signal between the forest (costs of overharvesting) and economy. This removes incentives within society to adjust use patterns to new conditions (striving for more efficient use and re-use, changing wasteful behaviors, developing innovations, etc.). As such, nations need a reference for when their consumption levels have surpassed this balance. Such a reference value must take both ecological limits and global equity into account to reflect the goals of sustainable development. For example, already in 1992, Agenda 21 stated: “Special attention should be paid to the demand for natural resources generated by unsustainable consumption… Although consumption patterns are very high in certain parts of the world, the basic consumer needs of a large section of humanity are not being met.” Agenda 21 [
28] implies that people in high consuming countries need to limit their total consumption to levels which allow others—at a bare minimum—to reach a basic quality of life. This includes consideration of other resource types. For example, growing timber in plantations (e.g., to fuel high and wasteful uses of energy in high income economies) using high amounts of fresh water in places where water is scarce and undernourishment is widespread would not contribute to overarching sustainable development goals.
In light of these concerns about (a) where the increasing demand for timber should be sourced, (b) how it should be grown, and (c) how much can be extracted within sustainability limits, a recent series of articles and publications argues for and makes the first steps toward developing the methodological basis for a systemic monitoring of EU timber and forest use [
29,
30,
31]. The first article [
30] developed an approach to account for primary timber flows of woody biomass in order to develop indicators of EU primary timber consumption (e.g., toward forest footprints
2). Best estimates found that EU consumption was around 1.6 times higher than the global average on a per capita basis in 2010. A second article [
31] developed a reference value range for EU and global sustainable supply capacities as a benchmark for sustainable consumption levels. On a per capita basis, it was found that the EU has more capacity for sustainable supply than the global average, in particular due to relatively high amounts of forest available for wood supply in the EU with high productivities. Which benchmark (global and/or territorial) is appropriate as an orientation for EU policy making was discussed at length. In 2010, European consumption levels were below the most realistic estimates of EU sustainable supply capacities but exceeded global sustainable supply capacity estimates on a per capita basis by more than 50% [
29]. This article builds on both articles [
30,
31] in order to better understand how EU and global timber consumption trends may develop in the future, both in comparison to each other as well as to future reference value ranges for sustainable consumption.
In this way, this article aims to contribute to developing a systemic monitoring perspective that takes potential future impacts of current policy decisions into account. It also aims to stress the need for considering trends of both production and consumption in monitoring natural resource use. It should be emphasized that this is a first step toward further developing such a consumption-based perspective for better understanding of what it means to promote a sustainable level of timber consumption as part of a sustainable development transition. Goal 12 of the Sustainable Development Goals aims to promote responsible consumption and production, with the target of achieving sustainable management and efficient use of natural resources by 2030
3. This article begins to look at the metrics to that end for timber and forests in more detail. In this sense, it uses and builds on available data and scenarios in a rather simplistic way to check first whether there is a problem and, upon highlighting risky trends, calls for much more robust methods and approaches to further develop a systemic monitoring system capable of providing strong policy recommendations.
This article begins with a literature review of timber consumption scenarios at the global and EU levels. These scenarios are the basis for checking whether future developments may stay within or exceed a potential sustainability corridor in the future. Results are presented and discussed, with future research needs emphasized. Conclusions summarize key findings and provide concise policy implications, in particular on the need for better monitoring.
4. Results
Global results depict a demand for primary raw timber of between around 4.2 and 7.2 Gm
3 in 2030 (
Figure 1). A comparison with the FAOSTAT extrapolated trend reveals that global consumption is expected to increase at a higher rate than in the last 50 years. At the global level, the difference between the A1 world and B2 world is distinctive, with the A1 scenario (which is characterized by high growth) showing a tremendous increase in the consumption of wood, which may not be the most plausible expectation for future developments.
In comparison to the sustainable supply range developed by O’Brien and Bringezu [
31] the A2 and B2 global scenarios based on Buongiorno, et al. [
35] are within or quite close to the upper threshold of the sustainable supply range until 2030. The scenario based on the A1 world with high economic growth and fuelwood demand quickly exceeds the sustainable supply range beyond 2010 (e.g., it exceeds the upper boundary by around 30% in 2030). The scenarios based on FAO data [
19], with high assumptions regarding fuelwood, reveal that the target space was already exceeded in 2010 and that this gap would continue to grow significantly until 2050. In 2030, the upper boundary of the sustainable supply range would be surpassed by around 65% according to those projections [
19]. The simple extrapolation showing a continuation of global trends from the last 50 years based on FAOSTAT data would just exceed the upper threshold of the sustainable supply range in 2030. Altogether, all long-term developments show an overshoot of the global sustainable supply reference range.
Figure 2 depicts results for the EU consumption scenarios compared to the EU sustainable supply range. In the year 2030, the EU would require between around 570 Mm
3 and 800 Mm
3 of primary timber to meet demands depending on the scenario (noting in comparison that the total demand for products and energy in the wood resource balance method (i.e., including secondary sources) was estimated by the EUWood project [
39] at 1372 Mm
3 in their A1 scenario for products + meeting renewable energy targets and 1280 Mm
3 in their B2 scenario for products + meeting renewable energy targets; EFSOS II [
18] estimated 989 Mm
3 in their reference scenario and 1234 Mm
3 in their promoting wood energy scenario in 2030).
Figure 2 shows that in the moderate growth scenario, around 140 Mm
3 more primary timber would be needed to meet renewable energy targets in comparison to the moderate scenario without reaching RES targets. Around 60% of demand in 2030 is comprised of fuelwood in the scenarios to meet RES targets and around 50% of demand is comprised of fuelwood in the scenario without reaching RES targets. As compared to the sustainable supply range,
Figure 2 reveals that consumption levels will most likely stay below the sustainable supply capacity of EU forests between 2010 and into the 2020s. In the scenarios to meet renewable energy targets, the upper boundary of the sustainable supply range is surpassed in 2024 in the high economic growth scenario and in 2030 in the moderate economic growth scenario. Again, it should be emphasized that primary demand growth may be overestimated, and that meeting higher levels of demand with secondary sources would change these dynamics, with potential implications for the interpretation of the moderate growth scenario, which overshoots the maximum sustainability threshold only at the end of the period. In the scenario with moderate growth and no meeting of renewable energy targets, EU consumption levels stay below or within the sustainable supply range. Altogether, the results imply that to meet renewable energy targets over the long term, the EU would become more dependent on imports and/or require much higher levels of mobilization in domestic forests, which could lead to overuse related to both forest degradation and forest loss. Dependence on increased imports may have similar negative effects if not controlled within a wider framework of sustainable resource management and equitable distribution, with a high concern in particular for raising biodiversity risks (considering in particular that the planetary boundary for biodiversity loss is estimated to have already been surpassed [
42,
46]). Alternatively, lower levels of primary timber demand for products (e.g., due to increased secondary sources and/or reduced demand due to e.g., paper substitution) could make more space for energy wood in the future.
Figure 3 compares global and EU per capita consumption levels estimated in the scenarios. It reveals significantly higher per capita consumption levels for the EU than the global average. EU consumption is 2 times higher than global average consumption comparing the lowest scenario estimates for both the EU and world in 2030 (in other words the moderate economic growth scenario (B2) in both cases, but without achievement of renewable energy targets in the EU). A comparison of the highest scenario estimates for both the EU and world reveals that EU consumption is 1.8 times higher than the global average (e.g., high economic growth and meeting renewable energy targets in the EU compared to trends based on FAO [
19] at the global level). Comparing trends within the IPCC scenarios reveals that in the A1 case (high economic growth), EU consumption is 2.3 times higher than the global average, whereas in the B2 case (moderate economic growth), EU consumption is 2.5 times higher than the global average (based on meeting renewable energy targets in the EU in both cases). This indicates that expected EU consumption levels, in particular to meet renewable energy targets, lead to highly disproportionate consumption patterns, which are between 1.8 and 2.5 times higher than the expected average consumption levels on a global basis in 2030.
Figure 4 depicts per capita consumption scenarios for the EU-27 from 2002 until 2030 compared to the EU and global reference value ranges. It reveals that EU consumption levels will likely stay below the EU reference value range between 2002 and 2020 for all scenarios, but that it has already surpassed the global per capita reference value range significantly. In 2030, the scenario with high economic growth and meeting renewable energy targets would lead to an EU consumption level that would exceed the upper threshold of the EU reference value range by around 15% and would be nearly 3 times higher than the upper threshold of the global reference value range. The scenario with moderate economic growth and meeting renewable energy targets would lead to an EU consumption level just over the upper threshold of the EU reference value range and nearly 2.6 times higher than the upper threshold of the global reference value range in 2030. Without meeting renewable energy targets and with moderate economic growth, the consumption of EU timber could stay below the EU reference value range in 2030 (it would cross the lower threshold of the reference value range in 2032), but would still be more than 2 times higher than the upper threshold of the global reference value range. This raises serious concerns about an import strategy in the future.
5. Discussion
Meeting around a 40% share of renewable energy targets in the EU with timber in 2020 and beyond would increase pressure on global land use with potential impacts on climate change and biodiversity. Results show that meeting renewable energy targets would cause total EU primary timber demand between 2010 and 2030 to increase by around 55 to 70% (while a total increase of 20% could be expected in the moderate growth scenario without meeting renewable targets). This increase implies that the EU would exceed its own sustainable supply capacity between 2024 and 2030, potentially making the EU import dependent (to maintain sustainable forest management practices “at home”). In 2030, total EU consumption would be just over to up to around 15% higher than the upper threshold of the EU reference value range and around 160 to 200% higher than the upper threshold of the global reference value range. It would thus contribute to the global overshoot of a safe operating space for forest use [
31] calculated in the global high growth scenarios. Specifically, two of the global scenarios already showed an overshoot of around 30 to 65% of the upper sustainable supply boundary, making an import strategy particularly questionable. Somewhat lower targets for energy wood as well as a slow down in product demand growth could ease pressures and make it possible for the EU moderate demand growth scenario to stay within a territorial EU sustainable supply range. This would imply the need for policies that promote sustainable harvesting and timber mobilization within the EU to meet those demands, in order to mitigate the risks associated with shifting production and harvesting abroad. However, such a moderate growth scenario would still be above the global reference value range, raising the question of which reference value range is appropriate for the EU to use as an orientation [
31].
Projected consumption levels within the EU are also shown to be highly disproportionate compared to the global average. Average EU consumption would exceed average global consumption levels by a factor of 1.8 to 2.6 in scenarios meeting renewable energy targets under comparable economic developments (e.g., A1 and B2 overarching storylines). In light of the “principle of equity” e.g., in the 2002 New Delhi Declaration [
43], such a development would raise risks of contributing to inter- and intra-generational inequity. Depending on how timber is sourced, it may also contribute to hindering the right to fair access of global resources (e.g., in cases of “land grabbing” for plantation establishment and forestry [
47]).
Results presented here present a culmination of findings in a ”series” of articles [
30,
31]. In sum, they point to the need for developing a systemic monitoring of the forest and forest-based sectors including an accounting of timber flows underlined by indicators (like the forest footprint) and sustainability benchmarks (like reference values—and eventually targets—for sustainable supply capacities from forests at different spatial dimensions). This article has highlighted the importance of taking the future perspective into consideration in order to develop smart policies for both timber and forest use in keeping with sustainability considerations. Research is needed to this end, with this article presenting first steps towards a conceptual framework and approach, which must be underpinned by more reliable data as well as methodological robustness in the future.
For example, at the global level, scenarios were based on two sources [
19,
35]. However, these scenarios showed high differences in the historical levels of consumption for fuelwood (due to different calculation methods) and the level of projected industrial roundwood in the future. This difference is due to different modeling and projection approaches, relying on economic modeling [
35] versus an aggregation of expected trends in different regions of the world from forest sector outlook studies [
19] (performed together with the FAO and regional experts) based on key drivers of change (regarding demography, economy and policies, in particular energy policies in Europe). This gap points to the need to improve methods and approaches for projecting timber demand, perhaps using a combination of bottom-up trends and top-down modeling, while also taking structural shifts occurring in the forest industry into account [
25], in particular as concerns bioenergy [
36] and the potentially growing bioeconomy. This relates to the need to better understand processes and trends on the supply side, in particular on better data for timber stemming from plantations [
48] as well as on forest management, use and relation to environmental challenges such as climate change [
4] and biodiversity loss [
49].
As regards the EU demand scenarios, strengthened methods are needed to account for primary timber consumption. Most literature sources include projections for consumption based on demand, regardless of whether this expected demand level shall come from primary raw timber or recycling flows. In order to make comparisons to the forest and the sustainable supply capacity, primary flows are needed, including for imports and exports, making also global trends regarding trade of re-used wood products an area for future research. The projections in this article are based on replicating trends given in literature sources and research is needed to develop a methodology and modeling scenarios to specifically address the questions posed in this article. In the future, expert judgment could be one approach to better distinguish primary and secondary sources for different types of flows. It should be noted that as the focus is on primary timber in the projections presented by this article, the total consumption of “timber equivalents” could be much higher in the safe operating space scenario if, e.g., more recycling flows are used. This also highlights the importance of innovation in the re-use and recycling of timber in the future (e.g., such as in cascading use [
50,
51,
52,
53]) in order to reduce the demand for primary timber. Increased use of secondary sources would mean more products can be offered within the bounds of the safe operating space.