Harvested Wood Products Carbon Research Articles

Towards a Carbon Accounting Framework for Assessing the Benefits of Biogenic Wood Carbon to Net Zero Carbon Targets

Carbon stored in harvested wood products (HWPs) can play an important role in climate change mitigation and needs to be accounted for accurately and consistently. This study reviewed the features of previous HWP carbon accounting frameworks and discussed potential improvements for a more complete assessment of all HWP contributions to net zero carbon targets at subnational levels. The basic features include the components, the methods, the approaches, and the modeling principles. A key recommendation is to expand previous HWP C accounting framework components to include other climate change mitigation benefits such as local or regional substitution effects (i.e., material replacement, fossil fuel displacement effects, energy efficiency gains, recycling effects, and cascading use impacts) of all produced and consumed HWPs. Another area for improvement is the need for subnational unit-specific activity data and conversion factors. Adopting variants of the domestic origin-stock change approach will also help account for relevant production and consumption activities within the subnational unit. These recommendations will enhance the accuracy and/or precision of HWP accounting frameworks at the subnational level and help capture all potential benefits of HWPs as a carbon sink for climate change mitigation and a valuable contributor to subnational net zero carbon targets.

Exploring plausible contributions of end-use harvested wood products to store atmospheric carbon in China

The lateral transfer of carbon from forests to end-use Harvested Wood Products (HWPs), such as furniture and buildings through harvesting and industrial processing, creates an end-use HWPs carbon pool. This carbon pool serves as a substantial storage for atmospheric carbon dioxide, thus contributing to the mitigation of greenhouse gas effects. As new wood products enter this carbon pool and old products are disposed of upon reaching the end of their service lives, monitoring the carbon inflow and outflow allows for assessment of the size of HWPs carbon pool. Numerous factors, including climate change, population, and economy, significantly influence the supply and demand for wood products, consequently affecting the size of this carbon pool. Therefore, incorporating crucial factors to project plausible futures of carbon stock in HWPs is essential for predicting land-atmospheric carbon exchange and regional carbon budgets. In this study, we compiled and analyzed historical records of wood production and trade data, outlined their plausible futures using a recursive dynamic economic equilibrium model, and employed a product-type and service-life based accounting approach to quantify the HWPs carbon pool in China. Our findings indicate that from 1961 to 2020, the end-use HWPs carbon pool in China functioned as a net annual carbon sink, sequestering 14.9 Tg C of carbon per year and accumulating a total of 893 Tg C, with 76% stored in furniture products. The model predictions suggest that the HWPs carbon pool could potentially sequester carbon up to 2979 ± 806 Tg C by 2070.

On Carbon Storage and Substitution Factors of Harvested Wood Products in the Context of Climate Change Impacts of the Norwegian Forest Sector

Harvested wood products (HWP) contribute to climate change mitigation via two main mechanisms: carbon storage and substitution. The authors examined the data on carbon storage and substitution factors of HWPs that are relevant in evaluating the climate change mitigation potential in the context of the Norwegian forest sector. While there seem to be many uncertainties in these parameters, the data suggest that several uses of wood for industrial products come with clear carbon substitution benefits and, in some cases, provide long-term carbon storage. Such wood products could play an important role in climate-friendly bioeconomic transformation. In particular, the authors considered wood- based construction materials, textile fibres, and insulation materials as examples of such products with potential in future bioeconomy. The decay of the carbon stored in HWP pools over time is often modelled using the product half-lives that correspond to the number of years it takes for the carbon in a pool to be reduced to half of its initial value. Using the default half-life values of greenhouse gases reported to the United Nations Framework Convention on Climate Change, the average half-life of carbon in HWPs produced by the forest industry in Norway of today is approximately 21 years. Shifting some of the use of pulpwood and sawn wood chips from producing paper and pellets to produce insulation materials or panels for construction would increase the time carbon is stored in the HWP pool. Accounting for the large uncertainty in the carbon substitution parameters of HWPs found in this study, a cautious estimate of the substitution benefits of HWPs produced in Norway can be considered to amount to at least 5 Mt CO2. Redirecting some pulpwood use from paper production to the production of textile fibres and the above-mentioned construction materials would increase the substitution benefits.

The potential for storing carbon by harvested wood products

Forest ecosystems are a critical component of the global carbon cycle, which stores carbon in both vegetation biomass and soil organic matter. Timber harvesting can laterally move the carbon stored in forest sectors to harvested wood products (HWPs) and thus create an HWPs carbon pool. The carbon stored in HWPs is allocated to end-use wood products (e.g., paper, furniture), landfills (e.g., waste wood materials), and charcoal (e.g., non-energy use biochar). Environmental change is predicted to have far-reaching effects on the carbon stored in HWPs by altering the timber supply. In addition, technological advancement in the wood industry accelerates the carbon inflow rate by promoting processing efficiency and reduces the outflow rate by creating innovative wood products with a longer service life. Socioeconomic factors such as population and household income also contribute to the carbon stock changes in wood products by expanding or reducing the demand. Given numerous factors that are correlated with the size of HWPs carbon pool, an advanced and comprehensive understanding of these factors on modifying the HWPs carbon storage is essential to modeling and predicting the carbon stored in HWPs, atmospheric CO2 concentration, and global warming; therefore, we reviewed, summarized, and discussed the function of these factors in regulating the carbon stored in HWPs.

Technological advancement expands carbon storage in harvested wood products in Maine, USA

Harvested wood products (HWPs) in-use, disposed to landfill, and the charcoal created by biomass fuel burning substantially store carbon and potentially mitigate the greenhouse gas effect. To quantify the HWPs carbon storage, we developed a carbon accounting framework, which has the ability to incorporate the influence of technological advancement on HWPs carbon storage. Through applying this framework together with the wood harvesting data of Maine, USA during the period of 1901–2019, we concluded that the current HWPs carbon pool size is 52 Tg C, which is 11% of the carbon stored in the entire forestry sector and wood products of Maine, USA. Technological advancement potentially increases the HWPs carbon storage by as much as 44% to 75 Tg C. In addition, the average net annual carbon sink can be increased from 0.44 Tg C to 0.63 Tg C. Production of innovative wood products with long service lives plays the most important role in expanding the HWPs carbon pool; however, the higher processing efficiency and recycling rate are less important.

Methodological Comparison of the Production Approach 2013 and 2019 for Quantifying the Carbon Stock in Harvested Wood Products in China

Harvested wood products (HWP) play an important role in global climate change mitigation. The Production Approach, an internationally accepted HWP carbon accounting approach by the Intergovernmental Panel on Climate Change (IPCC), has been revised several times to enhance the accuracy of the accounting results. This study compared the methodological differences in the Production Approach elaborated in the 2013 Revised Supplementary Methods and Good Practice Guidance Arising from the Kyoto Protocol (PA2013) and 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories (PA2019). We used PA2019 to calculate the HWP carbon stock in China under different wood utilization scenarios. In terms of recycling and reusing of recovered paper, we found that PA2019 has a more accurate representation of the increasing proportion of paper and paperboard materials produced using recovered paper in the world. In 2019, the HWP carbon stock in China was 815.94 Mt (1 Mt = 106 t) using PA2019. In detail, the carbon stock of sawnwood, wood-based panels, and paper and paperboard were 208.52 Mt, 559.73 Mt, and 47.69 Mt, respectively. Scenario simulation results show that half-life was an important factor that affecting HWP carbon stock. China can improve HWP carbon stock by increasing the recovered paper utilization rate for paper products or increasing the utilization rate of HWP with long half-life in construction (structural material). The additional carbon stock obtained by changing the utilization structure of wood and improve the half-life of HWP will not be large until decades later but nonetheless important.

The default methods in the 2019 Refinement drastically reduce estimates of global carbon sinks of harvested wood products

BackgroundThe stock dynamics of harvested wood products (HWPs) are a relevant component of anthropogenic carbon cycles. Generally, HWP stock increases are treated as carbon removals from the atmosphere, while stock decreases are considered emissions. Among the different approaches suggested by the Intergovernmental Panel on Climate Change (IPCC) for accounting HWPs in national greenhouse gas inventories, the production approach has been established as the common approach under the Kyoto Protocol and Paris Agreement. However, the 24th session of the Conference of the Parties to the United Nations Framework Convention on Climate Change decided that alternative approaches can also be used. The IPCC has published guidelines for estimating HWP carbon stocks and default parameters for the various approaches in the 2006 Guidelines, 2013 Guidance, and 2019 Refinement. Although there are significant differences among the default methods in the three IPCC guidelines, no studies have systematically quantified or compared the results from the different guidelines on a global scale. This study quantifies the HWP stock dynamics and corresponding carbon removals/emissions under each approach based on the default methods presented in each guideline for 235 individual countries/regions.ResultsWe identified relatively good consistency in carbon stocks/removals between the stock-change and the atmospheric flow approaches at a global level. Under both approaches, the methodological and parameter updates in the 2019 Refinement (e.g., considered HWPs, starting year for carbon stocks, and conversion factors) resulted in one-third reduction in carbon removals compared to the 2006 Guidelines. The production approach leads to a systematic underestimation of global carbon stocks and removals because it confines accounting to products derived from domestic harvests and uses the share of domestic feedstock for accounting. The 2013 Guidance and the 2019 Refinement reduce the estimated global carbon removals under the production approach by 15% and 45% (2018), respectively, compared to the 2006 Guidelines.ConclusionsGradual refinements in the IPCC default methods have a considerably higher impact on global estimates of HWP carbon stocks and removals than the differences in accounting approaches. The methodological improvements in the 2019 Refinement halve the global HWP carbon removals estimated in the former version, the 2006 Guidelines.

Inward- versus outward-focused bioeconomy strategies for British Columbia\u2019s forest products industry: a harvested wood products carbon storage and emission perspective

BackgroundBritish Columbia’s (BC) extensive forest resources provide climate change mitigation opportunities that are available to few other jurisdictions. However, as a consequence of the Mountain Pine Beetle outbreak and large-scale wildfires, BC is anticipating reduced roundwood harvest for the next decades. Progress towards more climatically efficient utilization of forest resources is needed. This research quantitatively compared the greenhouse gas emission consequences of nine harvested wood products trade and consumption strategies. Inward-focused strategies use wood products within Canada to achieve emission reduction objectives, while outward-focused strategies encourage exports of wood products.ResultsIn the business-as-usual baseline scenario, average emissions arising from BC-originated harvested wood products between 2016 and 2050 were 40 MtCO2e yr−1. The estimated theoretical boundaries were 11 MtCO2e yr−1 and 54 MtCO2e yr−1, under the scenarios of using all harvests for either construction purposes or biofuel production, respectively. Due to the constrained domestic market size, inward-focused scenarios that were based on population and market capacity achieved 0.3–10% emission reductions compared to the baseline. The international markets were larger, however the emissions varied substantially between 68% reduction and 25% increase depending on wood products’ end uses.ConclusionsFuture bioeconomy strategies can have a substantial impact on emissions. This analysis revealed that from a carbon storage and emission perspective, it was better to consume BC’s harvests within Canada and only export those products that would be used for long-lived construction applications, provided that construction market access beyond the US was available. However, restricting export of wood products destined for short-lived uses such as pulp and wood pellets would have significant economic and social impacts. On the other hand, inward-focused strategies had a small but politically and environmentally meaningful contribution to BC’s climate action plan. This study also revealed the conflicts between a demand-driven bioeconomy and targeted environmental outcomes. A hierarchical incentive system that could co-exist with other market drivers may help achieve emission reduction goals, but this would require a better quantitative understanding of wood products’ substitution effects. While the analyses were conducted for BC, other regions that are net exporters of wood products may face similar issues.

Effects of Wood Product Utilization on Climate Change Mitigation in South Korea

Many countries, including South Korea, decided to suspend the inclusion of harvested wood products in their Nationally Determined Contributions, as part of the carbon inventory, in 2016. The inclusion of harvested wood products in the national greenhouse gases inventory must ensure the accuracy of carbon accounting and its conformity with the policy direction. The method used for harvested wood product carbon accounting can influence the accuracy of carbon account value, as well as policy direction based on greenhouse gas accounting. This research evaluated the utilization of domestic wood resources in South Korea in terms of carbon storage impacts from the perspective of the cascading use of wood products. The study also compared the two accounting methods (Tier 2 and Tier 3) of carbon storage for the period from 1970 to 2080, assuming the current pattern of wood resource utilization for the next sixty years. The results show that the current utilization of domestic wood resources is inefficient in terms of climate change mitigation. The analysis shows that there is a significant difference between the Tier 2 and Tier 3 methods in carbon storage effects, and the amount of harvested wood products carbon stock calculated by the Tier 2 method was found to be approximately double that of Tier 3. This result implies that there is a possibility of overestimating the carbon storage of harvested wood products when using the Tier 2 method in the case of net timber-importing countries, such as South Korea. The study can provide guidance for designing timber resource management from the perspective of the cascading use of wood products in order to contribute to sustainable development goals, including climate change mitigation.

Boosting the EU forest-based bioeconomy: Market, climate, and employment impacts

This study adds to the scientific literature dealing with the climate change mitigation implications of wood substitution. Its main scientific contribution rests with the modelling approach. By fully integrating forest resource and wood-product markets modelling in quantitative scenario analysis, we account for international trade in wood products as well as impacts on EU forests and forest-based sector employment of an increased EU uptake of wood-based construction and/or biochemicals and biofuels. Our results confirm the crucial role of the sawmilling industry in the forest-based bioeconomy. Thus, boosting wood-based construction in the EU would be most effective in increasing EU production and employment—in logging and solid wood-products manufacturing, but also in sectors using sawmilling byproducts as feedstock. Vertical integration in wood-based biorefineries should thus be advantageous. The positive EU climate-change mitigation effects of increased carbon storage in harvested wood products (HWP) and material substitution from increased wood construction are more than offset by reduced net forests carbon sinks by 2030, due to increased EU harvests. Further, increased EU imports, resulting in lower consumption of sawnwood outside the EU, would reduce extra-EU long-life HWP carbon storage and substitution of GHG-intensive materials, highlighting the need for concerted international climate change mitigation.

Estimating New Zealand\u2019s harvested wood products carbon stocks and stock changes

BackgroundReducing net greenhouse gas emissions through conserving existing forest carbon stocks and encouraging additional uptake of carbon in existing and new forests have become important climate change mitigation tools. The contribution of harvested wood products (HWPs) to increasing carbon uptake has been recognised and approaches to quantifying this pool developed. In New Zealand, harvesting has more than doubled since 1990 while log exports have increased by a factor of 11 due to past afforestation and comparatively little expansion in domestic processing. This paper documents New Zealand’s application of the IPCC approaches for reporting contributions of the HWP pool to net emissions, in order to meet international greenhouse gas inventory reporting requirements. We examine the implications of the different approaches and assumptions used in calculating the HWP contribution and highlight model limitations.ResultsChoice of system boundary has a large impact for a country with a small domestic market and significant HWP exports. Under the Production approach used for New Zealand’s greenhouse gas inventory reporting, stock changes in planted forests and in HWPs both rank highly as key categories. The contribution from HWPs is even greater under the Atmospheric Flow approach, because emissions from exported HWPs are not included. Conversely the Stock Change approach minimises the contribution of HWPs because the domestic market is small. The use of country-specific data to backfill the time series from 1900 to 1960 has little impact but using country-specific parameters in place of IPCC defaults results in a smaller HWP sink for New Zealand. This is because of the dominance of plantation forestry based on a softwood mainly used in relatively short-lived products.ConclusionsThe NZ HWP Model currently meets international inventory reporting requirements. Further disaggregation of the semi-finished HWP end uses both within New Zealand and in export markets is required to improve accuracy. Product end-uses and lifespans need to be continually assessed to capture changes. More extensive analyses that include the benefits of avoided emissions through product substitution and life cycle emissions from the forestry sector are required to fully assess the contribution of forests and forest products to climate change mitigation and a low emissions future.

Improving Carbon Stock Estimates for In-Use Harvested Wood Products by Linking Production and Consumption-A Global Case Study.

We developed a method to better estimate the carbon stocks of in-use harvested wood products (HWP) by using the Eora multiregional input-output tables to link global HWP production and end uses, compared to existing global-scale studies that focused on semifinished HWP. Using the new method, we allocated global HWP to country-specific end uses, including solid HWP used in (1) construction, (2) furniture production, and (3) other end uses, and as (4) household and sanitary paper and (5) other paper and paper products, while the HWP carbon stocks in these end uses were estimated using the Stock Change Approach. We reported that HWP produced globally contained an annual average of 277.7 teragram carbon in 1992-2015, of which 63.0, 12.6, 76.7, 9.1, and 116.3 teragram carbon were consumed by the above five end uses, respectively. By 2015, the carbon stocks of global in-use HWP produced since 1992 accumulated to 2938 teragrams of carbon, of which the above five HWP end uses accounted for 1489, 268, 890, 0, and 291 teragrams of carbon, respectively. Country-specific HWP production and consumption varied significantly, with the eight leading consuming countries (United States, China, Japan, Canada, Germany, Russia, United Kingdom, and France) accounting for 69% of the global in-use HWP carbon stocks.

Global mitigation potential of carbon stored in harvested wood products

Carbon stored in harvested wood products (HWPs) can affect national greenhouse gas (GHG) inventories, in which the production and end use of HWPs play a key role. The Intergovernmental Panel on Climate Change (IPCC) provides guidance on HWP carbon accounting, which is sensitive to future developments of socioeconomic factors including population, income, and trade. We estimated the carbon stored within HWPs from 1961 to 2065 for 180 countries following IPCC carbon-accounting guidelines, consistent with Food and Agriculture Organization of the United Nations (FAOSTAT) historical data and plausible futures outlined by the shared socioeconomic pathways. We found that the global HWP pool was a net annual sink of 335 Mt of CO2 equivalent (CO2e)⋅y-1 in 2015, offsetting substantial amounts of industrial processes within some countries, and as much as 441 Mt of CO2e⋅y-1 by 2030 under certain socioeconomic developments. Furthermore, there is a considerable sequestration gap (71 Mt of CO2e⋅y-1 of unaccounted carbon storage in 2015 and 120 Mt of CO2e⋅y-1 by 2065) under current IPCC Good Practice Guidance, as traded feedstock is ineligible for national GHG inventories. However, even under favorable socioeconomic conditions, and when accounting for the sequestration gap, carbon stored annually in HWPs is <1% of global emissions. Furthermore, economic shocks can turn the HWP pool into a carbon source either long-term-e.g., the collapse of the USSR-or short-term-e.g., the US economic recession of 2008/09. In conclusion, carbon stored within end-use HWPs varies widely across countries and depends on evolving market forces.

Estimating in-use wood-based materials carbon stocks in Indonesia: Towards a contribution to the national climate mitigation effort

The carbon sequestered in harvested wood products (HWP) can contribute to climate change mitigation. As a fast-growing country with abundant forest resources, Indonesia potentially has vast HWP carbon stocks that need to be accurately assessed as a first step towards understanding the extent of their potential contribution in climate change mitigation. In this study, a dynamic materials stock and flow analysis for carbon in wood-based products in Indonesia was conducted, covering six end-use sectors. In general, only around 30.3% of the harvested wood (carbon mass) was converted into end-use materials in 2014, indicating a significantly low harvested wood conversion rate in Indonesia. There was a significant increase of wood-based products’ carbon stocks in Indonesia from 1961 to 2016. There were 72 (-17/+15) Mt-C of wood stocks in Indonesian society in 2016, or equivalent to 0.28 t-C/capita. Buildings (42%) and infrastructure (31%) were the largest contributors to in-use carbon stocks. The product lifetime uncertainty had a significant influence on the estimate of total society’s wood-based carbon stock. Indonesia’s in-use stock of wood-based products in 2008 was below its stock level of steel (1.2 times smaller) and cement (5.3 times smaller). Both wood-steel and wood-cement stock ratios showed declining trends, indicating a shifting trend to non-renewable materials use over the past decades. This is the first study that accounts for the in-use wood-based carbon stocks in a developing country. Its results can facilitate further quantitative environmental assessments of non-renewable materials substitution and could help framing materials use policies for climate change mitigation.

Life-cycle carbon budget of China's harvested wood products in 1900–2015

Harvested wood products (HWP) are essential carbon pool of the forestry sector and can play an important role in climate change mitigation. Since the 10th Conference of Parties to the United Nations Framework Conversion on Climate Change in 2009, HWP have been required to be included in forest management as an additional carbon pool in national greenhouse gas (GHG) inventory reports. China is the largest consumer of end-use HWP and the largest importer of primary HWP in the world. Thus, the carbon stocks and emissions of China's HWP must be accurately assessed for evaluating their contribution to the climate change mitigation potential of global HWP. We developed an analysis framework by using Stock-Change Approach to estimate China's HWP carbon stocks/emissions from a life-cycle perspective, which covers three HWP life-cycle stages, namely, manufacture, end use, and end-of-life disposal. Using this framework, we produced the first-ever life-cycle carbon budget for HWP consumed by China in the period 1900–2015, based on a comprehensive analysis of China-specific data. From 1900 to 2015, total wood fiber input to the HWP carbon system in China was estimated to be 8049 teragrams of carbon dioxide-equivalent (Tg CO2-eq). Of the total wood fiber input, discarded mill residue, in-use HWP, and HWP disposed of at solid waste disposal sites retained 513, 3284, and 659 Tg CO2-eq of carbon, respectively, with the remaining 3591 Tg CO2-eq of wood carbon released back to the atmosphere. Of the total emission, combustion and decomposition of mill residue, burning of fuelwood, and combustion and decomposition of retired HWP accounted for 36.5%, 24.6%, and 38.9%, respectively. Landfill methane emissions were estimated to be 780 Tg CO2-eq after considering the global warming potential of this greenhouse gas. The net HWP carbon stocks, the sum of the carbon retained by discarded mill residue and the carbon stocks of HWP in use and in landfills, minus landfill methane emissions, increased from 297 Tg CO2-eq in 1950 to 4456 Tg CO2-eq in 2015.

An estimate of carbon stocks for harvested wood products from logs exported from New Zealand to China

In 2015 New Zealand exported 10.5 Mm3 of logs to China. A model has been developed to quantify the carbon stocks of harvested wood products (HWP) manufactured in China from these logs and the life cycle of the HWP produced. The model allows the aggregate decay curve of the HWP carbon stock to be estimated together with the 95% confidence interval. Overall, the HWP produced in China from New Zealand logs are short-lived with an aggregate half-life of just under two years. Some 46% of the HWP is lumber and plywood used for temporary construction while 13% is used for packaging which is also short-lived. There is a long tail in the carbon decay curve with 10% of HWP still in use after 23 years. Longer lived products are the 9% of HWP used for appearance products including furniture as well as panel products produced from a proportion of sawmill and plymill residues.Logs have been exported to China annually since 1987 and at levels exceeding 5 Mm3/year since 2010. The total HWP carbon stock from historical log exports is estimated to be 22.7 Mt CO2 at the end of 2015 with a 95% confidence interval of 19.1–26.4 Mt CO2. The annual increase for 2015 is estimated to be 1.9 ± 0.5 Mt CO2.The model developed will support New Zealand in meeting UNFCCC carbon reporting and Kyoto Protocol carbon accounting requirements. The analysis highlighted the importance of certain model inputs on which future effort should be focused.

Assessing the greenhouse gas effects of harvested wood products manufactured from managed forests in Canada

We developed a life-cycle analysis (LCA) system to quantify the carbon dynamics for Canadian-made harvested wood products (HWP). We considered the carbon stocks of HWP in use and in landfills/dumps, emissions reduced by substituting HWP for non-wood construction materials, HWP production emissions and methane emissions from decomposing wood disposed of in landfills. Carbon dynamics analyses were conducted for five HWP production scenarios. Results indicate structural panels have the highest potential in mitigating greenhouse gases (GHG) emissions, followed by lumber and non-structural panels. Net GHG effects of Canadian-made HWP were evaluated by integrating HWP carbon dynamics with forest carbon analysis using four forest management units (a total of 2.21 million ha of forests managed for timber production) from Ontario, Canada, as a case study. If HWP substitution benefits were estimated using the average displacement factor, and the wood obtained by increasing harvesting (relative to the baseline harvest scenario) in these four management units is used for structural panel, lumber, non-structural panel and business as usual HWP production, 0, 21, 39 and 84 years are needed to achieve net emission reductions, respectively; net emission reductions were, respectively, estimated to be 112, 93, 66 and 21 Mt CO₂-equivalent in 100 years. Our results suggest harvesting sustainably managed forests in Canada to produce long-lived solid HWP can significantly contribute to GHG mitigation.

Review of carbon storage function of harvested wood products and the potential of wood substitution in greenhouse gas mitigation

Global forests have the potential to significantly increase or reduce atmospheric greenhouse gas (GHG) concentration. Harvested wood products (HWP) are an important part of the forest-atmosphere carbon cycle. On the one hand, HWP can retain the carbon for various periods of time, depending on the end uses. On the other hand, using HWP in place of more GHG-intensive materials and using wood bioenergy to substitute for fossil fuels result in reduced fossil fuel emissions. However, critical methodological differences exist in existing literature in assessing the GHG effects of HWP and wood bioenergy substitution, and large diversity in system boundary, substitution scenario, study period, and reference baseline results in large difference in reported GHG effects of wood substitution. In the present study, we conducted a comprehensive literature review to (a) clarify the methodological issues in GHG effects assessments of HWP and wood bioenergy substitution, (b) summarize and compare the reported GHG effects, and (c) identify knowledge gaps to inform future research. We support the conclusion that to accurately assess the GHG effects, HWP and wood bioenergy life-cycle carbon analysis needs to be integrated with forest carbon balance analysis. Substituting HWP for non-wood materials appears to be more effective in reducing GHG emissions than substituting wood for fossil fuels. The time required to obtain net emission reduction for wood bioenergy in place of fossil fuels can be 0years, decades or more than a century, depending on forest biomass sources (e.g., harvest residue, standing live trees) and fossil fuels displaced. For HWP used to replace non-wood material, however, the time required to obtain net emission reduction largely remains a future research need. Overall, HWP and wood bioenergy originated from sustainably managed forests can significantly contribute to GHG emissions reduction in the long term.

Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change.

The carbon sequestration of harvested wood products (HWP) plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013) (IPCC), this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China’s HWP carbon pool increased from 130 Teragrams Carbon (TgC) in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China.

Life Cycle Analysis of Carbon Flow and Carbon Footprint of Harvested Wood Products of Larix principis-rupprechtii in China

Larix principis-rupprechtii is a native tree species in North China with a large distribution; and its harvested timbers can be used for producing wood products. This study focused on estimating and comparing carbon flows and carbon footprints of different harvested wood products (HWPs) from Larix principis-ruppechtii based on the life cycle analysis (from seedling cultivation to HWP final disposal). Based on our interviews and surveys, the system boundary in this study was divided into three processes: the forestry process, the manufacturing process, and the use and disposal process. By tracking carbon flows of HWPs along the entire life cycle, we found that, for one forest rotation period, a total of 26.81 tC/ha sequestered carbon was transferred into these HWPs, 66.2% of which were still stored in the HWP when the rotation period had ended; however, the HWP carbon storage decreased to 0.25 tC/ha (only 0.9% left) in the 100th year after forest plantation. The manufacturing process contributed more than 90% of the total HWP carbon footprint, but it was still smaller than the HWP carbon storage. In terms of the carbon storage and the carbon footprint, construction products had the largest net positive carbon balance compared to furniture and panel products. In addition, HWP are known to have a positive impact on global carbon mitigation because they can store parts of the sequestered carbon for a certain period of time and they have a substitution effect on carbon mitigation. Furthermore, there still exist great opportunities for carbon mitigation from HWPs through the use of cleaner energy and increasing the utilization efficiency of wood fuel.