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Climate change mitigation technologies have been a focus in reducing atmospheric carbon levels for the past few years. One such mitigation technology is pyrolysis, where biomass feedstocks are combusted at elevated temperatures for varying durations to produce three main products: biochar, bio-oil, and biogas. While bio-oil and biogas are typically used to produce energy via further combustion, biochar can be used in several different applications. Furthermore, using forest harvest residues as a feedstock for biochar production helps use excess biomass from the forestry industry that was previously assumed unmarketable. In our study, we combined forest carbon analysis modelling with cradle-to-gate life cycle emissions to determine the greenhouse gas emissions of biochar produced from forest harvest residues. We examined three collection scenarios, spanning two harvesting methods in one forest management unit in northern Ontario, Canada. From our analysis, we observed immediate reductions (− 0.85 tCO2eq·tbiochar−1 in year 1) in CO2-equivalent emissions (CO2eq) when producing biochar from forest harvest residues that would have undergone controlled burning, without considering the end use of the biochar. For the forest harvest residues that would remain in-forest to decay over time, producing biochar would increase overall emissions by about 6 tCO2eq·tbiochar−1. Throughout the 100-year timeframe examined–in ascending order of cumulative emissions–scenario ranking was: full tree harvesting with slash pile burn < full tree harvesting with slash pile decay < cut-to-length/tree-length harvesting. Highlights: Cradle-to-gate life cycle analysis for biochar production was evaluated. Forest harvest collection methods influence overall life cycle emissions for biochar. Harvest residues that typically undergo controlled burning are an ideal feedstock. [ABSTRACT FROM AUTHOR]

Forest canopy structural complexity (CSC) plays a crucial role in shaping forest ecosystem productivity and stability, but the precise nature of their relationships remains controversial. Here, we mapped the global distribution of forest CSC and revealed the factors influencing its distribution using worldwide light detection and ranging data. We find that forest CSC predominantly demonstrates significant positive relationships with forest ecosystem productivity and stability globally, although substantial variations exist among forest ecoregions. The effects of forest CSC on productivity and stability are the balanced results of biodiversity and resource availability, providing valuable insights for comprehending forest ecosystem functions. Managed forests are found to have lower CSC but more potent enhancing effects of forest CSC on ecosystem productivity and stability than intact forests, highlighting the urgent need to integrate forest CSC into the development of forest management plans for effective climate change mitigation.. [ABSTRACT FROM AUTHOR]

Data acquisition for sustainable forest management has focused on obtaining high quality information to estimate biomass. Improving the quality of non-timber sustainability indicators, like deadwood volume, has been a minor interest. To explore how inventory approaches could be improved, we applied a Global Uncertainty and Sensitivity Analysis (GUSA) to evaluate which factors propagate more errors in deadwood modelling and how better data collection can minimize them. The impact of uncertainty on deadwood characteristics (diameter, collapse ratio, decay class, tree species, and position) was explored under stakeholders´ preferences, management actions, and climate change scenarios. GUSA showed that removing the prediction error in deadwood tree species and diameter would alter the most the total uncertainty in deadwood volume. We found that assessment of high deadwood volume was less uncertain for the scenarios where small deadwood items were left decaying on the forest floor (BAU) and for high-end climate change scenario (RCP8.5) which resulted in lower deadwood accumulation in forest stands and therefore also in lower likelihood of erroneous estimates. Reduced uncertainty in tree species and diameter class will elevate the certainty of deadwood volume to a similar level achieved in living biomass estimation. Our uncertainty and sensitivity analysis was successful in ranking factors propagating errors in estimate of deadwood and identified a strategy to minimize uncertainty in predicting deadwood characteristics. The estimation of uncertainty in deadwood levels under the scenarios developed in our study can help decision makers to evaluate risk of decreasing deadwood value for biodiversity conservation and climate change mitigation. [ABSTRACT FROM AUTHOR]

Improving the precision of aboveground biomass (AGB) estimation in lowland tropical forests is crucial to enhancing our understanding of carbon dynamics and formulating climate change mitigation strategies. This study proposes an AGB estimation method for lowland tropical forests in Xishuangbanna, which include various vegetation types, such as Pinus kesiya var. langbianensis, oak, Hevea brasiliensis, and other broadleaf trees. In this study, 2016 forest management inventory data are integrated with remote sensing variables from Landsat 8 OLI (L8) and Sentinel 2A (S2) imagery to estimate forest AGB. The forest age and aspect were utilized as stratified variables to construct the random forest (RF) models, which may improve the AGB estimation accuracy. The key findings are as follows: (1) through variable screening, elevation was identified as the main factor correlated with the AGB, with texture measures derived from a pixel window size of 7 × 7 perform best for AGB sensitivity, followed by 5 × 5, with 3 × 3 being the least effective. (2) A comparative analysis of imagery groups for the AGB estimation revealed that combining L8 and S2 imagery achieved superior performance over S2 imagery alone, which, in turn, surpassed the accuracy of L8 imagery. (3) Stratified models, which integrated aspect and age variables, consistently outperformed the unstratified models, offering a more refined fit for lowland tropical forest AGB estimation. (4) Among the analyzed forest types, the AGB of P. kesiya var. langbianensis forests was estimated with the highest accuracy, followed by H. brasiliensis, oak, and other broadleaf forests within the RF models. These findings highlight the importance of selecting appropriate variables and sensor combinations in addition to the potential of stratified modeling approaches to improve the precision of forest biomass estimation. Overall, incorporating stratification theory and multi-source data can enhance the AGB estimation accuracy in lowland tropical forests, thus offering crucial insights for refining forest management strategies. [ABSTRACT FROM AUTHOR]

In recent years, the Can Gio district in Vietnam has faced escalating challenges linked to climate change, including deforestation, urbanization, and rising carbon emissions. This study employs remote sensing techniques to estimate critical forest metrics, particularly aboveground biomass (AGB) and carbon sequestration potential in the region. Through meticulous data collection and analysis, this research establishes strong correlations between vegetation indices derived from remote sensing data and AGB, as well as CO2 absorption. Our results reveal that the Can Gio mangrove forest boasts an impressive AGB ranging from 200 to 500 tons/ha and demonstrates significant variations in carbon sequestration potential across different sub-zones. These findings not only contribute to efficient AGB estimation methods but also facilitate sustainable forest management and climate change mitigation strategies, vital for the Can Gio district and regions globally grappling with similar challenges. [ABSTRACT FROM AUTHOR]

Forests are a vital source of food, fuel, and medicine and play a crucial role in climate change mitigation. Strategic and policy decisions on forest management and conservation require accurate and up-to-date information on available forest resources. Forest inventory data such as tree parameters, heights, and crown diameters must be collected and analysed to monitor forests effectively. Traditional manual techniques are slow and labour-intensive, requiring additional personnel, while existing non-contact methods are costly, computationally intensive, or less accurate. Kenya plans to increase its forest cover to 30% by 2032 and establish a national forest monitoring system. Building capacity in forest monitoring through innovative field data collection technologies is encouraged to match the pace of increase in forest cover. This study explored the applicability of low-cost, non-contact tree inventory based on stereoscopic photogrammetry in a recently reforested stand in Kieni Forest, Kenya. A custom-built stereo camera was used to capture images of 251 trees in the study area from which the tree heights and crown diameters were successfully extracted quickly and with high accuracy. The results imply that stereoscopic photogrammetry is an accurate and reliable method that can support the national forest monitoring system and REDD+ implementation. [ABSTRACT FROM AUTHOR]

With its northern location, the exposure and vulnerability of Canada's forest ecosystems to climate change impacts are all too glaring. While there is now an extensive body of literature describing expected climate change impacts and potential responses, studies characterizing the implementation of adaptation and mitigation practices in forest management remain rare in the Canadian forest sector. Using a systematic literature review, we examined reports on forest management practices implemented in response to climate change, specifically focusing on governance and institutional arrangements that either support or limit climate change adaptation and mitigation responses. Our literature sample size of 24 documents suggests that the body of literature reporting on adaptation and mitigation practices in forest management is scarce. Governments remain the dominant actors providing funding and leading the implementation and reporting of climate change adaptation practices, primarily in response to national or international climate change commitments. Forest practices such as enhanced silviculture, assisted migration, and nature-based solutions were the most frequently reported. However, given the scarcity of literature, it is difficult to conclude the scope of climate change adaptation practice uptake in Canada. Barriers such as lack of information/data, inter-jurisdictional knowledge transfer, policy conflicts, forest tenure models, technical capacity gaps, and economic barriers to adaptation need to be overcome to strengthen climate change response in forest management. Better coordination of reporting at the provincial and national levels and improved information flows between private sector organizations and governments are needed. [ABSTRACT FROM AUTHOR]

Canada is recognized as a global leader in sustainable forest management. Canadian forests and the forest sector remain vital pillars of the Canadian economy and home to many rural and remote communities. However, climate change is an existential threat to the sustainability of forests and forest-dependent communities. While both direct and indirect threats posed by climate change to Canada's forest sector are now well understood, our understanding of specific forest practices that have emerged from the body of science to mitigate and adapt to climate change impacts is not well documented. Through a review of the scientific and grey literature, this study expands our knowledge and operational gaps associated with implementing climate change adaptation and mitigation practices in Canadian forests. The study found a dearth of literature specifically dedicated to reporting on the type of forest practices currently in use across Canada to address mitigation and adaptation. Most reports or studies were published in 2019 or later, with federal and provincial governments being the dominant actors in reporting and monitoring, research, and funding. Across the 15 terrestrial ecozones in Canada, forest practices linked to climate change were reported in 12 ecozones, with most practices reported in the Montane Cordillera located in western Canada. Common forest practices reported include fuel management, assisted migration, enhanced silvicultural activities, and carbon offset projects. We conclude that climate change adaptation/mitigation practices in Canada are in their early stages of implementation. Many practices remain in experimental stages (e.g., genetic trials) or are implemented at a relatively small scale in Canada (e.g., climate-based seed transfer and carbon reserves). The literature suggests that the most mainstream practices associated with climate change mitigation in Canada include tree planting for carbon sequestration and the designation of protected areas to enhance ecosystem resilience. We conclude that despite increasing reports linking climate change benefits with reported forest practices, the reporting in the scientific literature is scarce, poorly reported, and often not grounded in credible evidence. [ABSTRACT FROM AUTHOR]

Aim: Despite mounting empirical evidence regarding the positive effects of forest structural diversity (STRDIV) on forest functioning, the underlying biotic mechanisms and controlling abiotic factors remain poorly understood. This study provides the first assessment of the interactive effects of STRDIV and diversity in species and functional traits on aboveground biomass (AGB) in natural forests in West and East Africa. Location: West and East Africa. Time period: 2014–2020. Major taxa studied: Woody plants. Methods: Using data from 276 plots and 7993 trees of 207 species distributed across various types of natural forests and major climatic zones of Africa, linear mixed‐effects and structural equation models, we have evaluated how alternative causal relationships between STRDIV and taxonomic and functional diversity attributes influence AGB, while accounting for the effects of environmental covariates. We also assessed the consistency of these relationships across floristically and environmentally homogenous forest types. Results: We found that the positive effects of STRDIV on AGB were underpinned by both the community‐weighted mean (CWM) of trait values (selection effects) and species richness (niche complementarity), but the relative importance of these effects varied depending on forest types. Across the forest types, STRDIV primarily mediated the effects of CWM of traits and species richness on AGB. We also found that STRDIV–AGB relationships were constrained by resource (water and nutrient) availability. Main conclusions: Our findings provide novel insights into the role of functional traits as key determinants of the effects of STRDIV on AGB in tropical forests. We suggest that forest management and climate change mitigation strategies aimed at conserving biodiversity, and fostering biomass storage through increased STRDIV should focus on maintaining high levels of functionally dominant species while also increasing tree species diversity. [ABSTRACT FROM AUTHOR]

Sustaining forest carbon sinks is a priority in climate change mitigation and forest management strategies. However, several issues confront the role of Philippine forests in climate change mitigation. These include the loss of old-growth cover, unsustainable forest landuse practices, and lack of site-specific modelling. These are the realities in the Quirino Forest Landscape Project (QFLP), a semi-contiguous collection of secondary forests in four municipalities of Quirino Province. This study was undertaken to develop a forecast model for carbon in aboveground of underutilised trees in QFLP. Data were collected through field inventory, the National Mapping and Resource Information Authority Land Cover Databases, and secondary sources. Multiple linear regression, principal components analysis, and biodiversity indices were used to analyse the data collected from different sampling areas to develop a forecast model. Findings suggest that the QFLP forest was secondary, as evidenced by the fact that > 60% of the trees were underutilised. With the ongoing decline in forest cover due to resource use and lack of forestry policy enforcement, it is worth noting that the carbon sequestration potential of underutilised species is not dependent on ecological dominance; that is, species that are more vulnerable to local extinction have higher potential to gain carbon. Given all the variables and their high forecasting power, the study demonstrated that the developed model was precise enough to provide future carbon capture values for QFLP. [ABSTRACT FROM AUTHOR]

The conservation, restoration, and improved management of terrestrial forests significantly contributes to mitigate climate change and its impacts, as well as providing numerous co‐benefits. The pressing need to reduce emissions and increase carbon removal from the atmosphere is now also leading to the development of natural climate solutions in the ocean. Interest in the carbon sequestration potential of underwater macroalgal forests is growing rapidly among policy, conservation, and corporate sectors. Yet, our understanding of whether carbon sequestration from macroalgal forests can lead to tangible climate change mitigation remains severely limited, hampering their inclusion in international policy or carbon finance frameworks. Here, we examine the results of over 180 publications to synthesise evidence regarding macroalgal forest carbon sequestration potential. We show that research efforts on macroalgae carbon sequestration are heavily skewed towards particulate organic carbon (POC) pathways (77% of data publications), and that carbon fixation is the most studied flux (55%). Fluxes leading directly to carbon sequestration (e.g. carbon export or burial in marine sediments) remain poorly resolved, likely hindering regional or country‐level assessments of carbon sequestration potential, which are only available from 17 of the 150 countries where macroalgal forests occur. To solve this issue, we present a framework to categorize coastlines according to their carbon sequestration potential. Finally, we review the multiple avenues through which this sequestration can translate into climate change mitigation capacity, which largely depends on whether management interventions can increase carbon removal above a natural baseline or avoid further carbon emissions. We find that conservation, restoration and afforestation interventions on macroalgal forests can potentially lead to carbon removal in the order of 10's of Tg C globally. Although this is lower than current estimates of natural sequestration value of all macroalgal habitats (61–268 Tg C year−1), it suggests that macroalgal forests could add to the total mitigation potential of coastal blue carbon ecosystems, and offer valuable mitigation opportunities in polar and temperate areas where blue carbon mitigation is currently low. Operationalizing that potential will necessitate the development of models that reliably estimate the proportion of production sequestered, improvements in macroalgae carbon fingerprinting techniques, and a rethinking of carbon accounting methodologies. The ocean provides major opportunities to mitigate and adapt to climate change, and the largest coastal vegetated habitat on Earth should not be ignored simply because it does not fit into existing frameworks. [ABSTRACT FROM AUTHOR]

The Reducing Emissions from Deforestation and Degradation (REDD+) projects aim to prevent deforestation and greenhouse gas emissions as a policy to combat climate changes. This article evaluates changes to the Zagros' Forest cover in 20 years and predicts the implications of implementing the REDD+ project in the next two decades. Using Landsat Forest cover maps and a logistic regression model the potential for forest cover transfer to non-forest regions was modeled to identify regions at risk of deforestation. A Markov chain was implemented to predict the changes. Receiver Operating Characteristics (ROC) was employed for validation, and the Voluntary Carbon Standard (VCS) was utilized to model the REDD+ project baseline to predict the forest cover changes. The findings indicate, 37,809 hectares of forest cover were lost in the past 20 years and with this trend, the amount of greenhouse gas emissions will increase. However, implementing the REDD+ project can prevent the release of 1,714,534.13 tCO2e. Therefore, this deteriorating forest possesses the potential to reduce CO2 emissions by preventing deforestation, identifying deforestation-prone areas and implementing the REDD+ project utilizing the methodology presented. Climate change mitigation, carbon sequestration, and biodiversity protection are just a few of the benefits of REDD+ projects that can aid sustainable forest management [ABSTRACT FROM AUTHOR]

Meeting climate change mitigation targets by 2050, as outlined in international pledges, involves determining optimal strategies for forest management, wood supply, the substitution of greenhouse gas‐intensive materials and energy sources, and wood product disposal. Our study quantified the cumulative mitigation potential by 2050 of the forest sector in the province of Quebec, Canada, using several alternative strategies and assessed under what circumstances the sector could contribute to the targets. We used the Carbon Budget Model of the Canadian Forest Sector to project ecosystems emissions and sequestration of seven alternative and one baseline (business‐as‐usual [BaU]) forest management scenarios over the 2018–2050 period. Three baskets of wood products were used in a Harvested Wood Products model to predict wood product emissions. The mitigation potential was determined by comparing the cumulative CO2e budget of each alternative scenario to the BaU. The proportion of methane emissions from landfills (RCH4%) and the required displacement factor (RDF) to achieve mitigation benefits were assessed both independently and jointly. The fastest and most efficient way to improve mitigation outcomes of the forest sector of Quebec is to reduce end‐of‐life methane emissions from wood products. By reducing methane emissions, the RDF for achieving mitigation benefits through intensification strategies can be reduced from 1.2–2.3 to 0–0.9 tC/tC, thus reaching the current provincial mean DF threshold (0.9). Both a reduction and an increase in the harvested volume have the potential to provide mitigation benefits with adequate RCH4% and RDF. Increased carbon sequestration in ecosystems, innovations in long‐lived wood products, and optimal substitution in markets offer potential avenues for the forest sector to contribute to mitigation benefits but are subject to significant uncertainties. Methane emission reduction at the end of wood product service life is emerging as a valuable approach to enhance mitigation benefits of the forest sector. We determined the Quebec forest sector's carbon mitigation potential using alternative strategies (forest ecosystems/product decay/substitution). We estimated the displacement factors that are required for wood products by 2050. We estimated the landfill CH4 emission reductions that must be achieved by 2050. Conservation alternatives increase carbon sinks by 2050, and intensification alternatives increase carbon sources by 2050. With improved methane management and optimal substitution, both conservation and intensification scenarios could provide mitigation benefits. Quebec's forests sector can contribute to enhanced climate mitigation benefits if sustainable forest management, optimum use of wood, and improved methane management of landfills are achieved. [ABSTRACT FROM AUTHOR]

Forests and the dynamic changes play decisive roles in soil erosion prevention, biodiversity conservation and climate warming mitigation, and are crucial for China to achieve carbon neutrality because of the ability for carbon uptake. China's forests experienced a substantial change over the past century, primarily since the forest conservation and restoration programs were implemented. In this paper, the progress of China's forest change and the similarities and differences of the spatio-temporal patterns from multi-dimension coupling with ground surveys and satellite observations were reviewed comprehensively, and the drivers of forest change were discussed. Our review reported that: 1) China's forests experienced an extensive forest gain/restoration in vegetation greenness, forest cover, and aboveground biomass since the 1970s. 2) Changes in various forest parameters suggested distinctive spatiotemporal patterns in China. Consistent hotspots of forest gain clustered in the Loess Plateau and the southwestern China from most studies, while controversial conclusions about forest loss/degradation were found in the spatial distribution. 3) The geographic discrepancy of forest changes may be related to climate change, human activities, and forest disturbances. Variations in forest dynamics are prerequisites to exploring the effects of natural conditions and forestry policies on forest cover, and strengthening understanding of the carbon cycle. These findings can provide valuable insights for various ecological services in further studies and a scientific basis for forest management and policy-making in China. [ABSTRACT FROM AUTHOR]

Discussion on reducing emissions from deforestation in developing countries began at the United Nations Framework Convention on Climate Change (UNFCCC) Conference of the Parties in 2005, and the agenda for "reducing emissions from deforestation and forest degradation, and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries (REDD+)" was introduced under the UNFCCC. The REDD+ framework was developed with the expectation that it would significantly contribute to climate change mitigation at a relatively low cost and produce benefits for both developed and developing countries. Finance is a key element of REDD+ implementation, and many financial sources, approaches, and mechanisms have supported REDD+-related activities in various developing countries. However, the comprehensive challenges and lessons learned for REDD+ finance and its governance have not been fully explored. This paper reviews the relevant literature to understand the challenges for REDD+ finance and its governance in two areas—(1) REDD+ finance aligned with the UNFCCC and (2) REDD+-related finance outside the UNFCCC—which have developed differently and have different implications. This paper first identifies the six key elements of REDD+ finance and its governance across the two fields, and then reviews the related challenges and lessons learned with respect to public and private finance. The challenges for REDD+ finance and its governance aligned with the UNFCCC include enhancing the performance of REDD+ finance using mainly public finance, such as results-based finance and the jurisdictional approach. In contrast, the challenges regarding REDD+-related finance outside the UNFCCC include enhancing the engagement of the private sector in REDD+ finance, mainly targeting the project level, and the relationship between voluntary carbon markets and other investment and finance mechanisms. This paper also identifies the common challenges across REDD+ finance and its governance in the two fields. These challenges include the need to enhance linkages between REDD+ and other objectives, such as carbon neutrality/net-zero, deforestation-free supply chains, and nature-based solutions, as well as the need to develop learning systems for REDD+ finance. [ABSTRACT FROM AUTHOR]

United Nations Educational, Scientific and Cultural Organisation (UNESCO) strives to increase the number of natural World Heritage Sites to protect it from the onslaught of climate change and anthropogenic disturbances. The international community at the Paris Agreement on climate change in 2015 recognized reducing emissions from deforestation and forest degradation and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks in developing countries as one of the best low cost panacea for global environmental problems. India, in its Nationally Determined Contributions (NDCs) promised to increase its forest cover as an effort toward the mitigation of climate change. All these efforts are directed toward saving our Earth from the worst impacts of global warming. In the midst of these efforts, the conservation of Western Ghats is one of the central hotspots of biodiversity and deserves special attention. Thus, this paper looks into the questions how the Heritage Tag and Western Ghats Ecology Expert Panel (WGEEP) report causes intricacies in the conservation of Western Ghats? And why local inhabitants are so much apprehensive about the conservation of their region? This study proves that negligence in addressing the concerns and participation of affected stakeholders, from the framing of the conservation projects to its implementation, leads anti-conservation movements. Additonally, such conservation projects will never break ground and will remain on paper. [ABSTRACT FROM AUTHOR]

Background: In Ethiopia, highland bamboo has been cultivated in various niches: farmlands, riverbanks, woodlot boundaries, and homesteads, and agroforestry systems. However, the biomass and carbon storage of potential of bamboo forests across niches is not well characterized in Ethiopia. Therefore, this study was conducted to estimate the biomass and carbon storage potential of highland bamboo plantations in northwestern Ethiopia. To this end, a total of 60 circular plots measuring 100 m2 with a radius of 5.64 m were randomly established on the homestead, woodlot, and riverbank plantation niches to conduct the inventory. The biomass storage of bamboo was calculated based on previously published allometric equations. Biomass and carbon stock variations among age-classes and niches of bamboo forests were analyzed using analysis of variance (ANOVA) and subsequent pairwise means comparisons of carbon stocks among niches were performed via post hoc Tukey test at p < 0.05. Results: Results showed that the mean aboveground biomass (AGB) ranged from 150.18 – 191.42 Mg ha−1 in the entire niches. The highest amount of AGB was stored in the homestead niche (191.42 Mg ha−1) followed by the woodlot (180.11 Mg ha−1) and riverbank niche (150.17 Mg ha−1), respectively. The highest carbon stock (111.56 Mg C ha−1) was found in the homestead niche while the smallest amount was recorded in the riverbank niche (87.52 Mg ha−1). The homestead bamboo plantation has the highest biomass storage due to the application of manure and natural fertilizer, regular harvesting and management of culms, and protection from illegal harvesting and grazing. Conclusion: This study highlights the importance of bamboo plantations in climate change mitigation. Hence, bamboo plantation should be promoted; and natural resource management and forestry departments of the government, Universities, research centers, the International Bamboo and Rattan Organization (INBAR), and other partners should work with local communities to expand bamboo plantation on their homesteads and degraded lands. [ABSTRACT FROM AUTHOR]

Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long‐term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground‐based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m3 of disturbed timber volume per year over the 70‐year study period. This value is likely a conservative estimate due to under‐reporting, especially of small‐scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m3/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long‐term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes. [ABSTRACT FROM AUTHOR]

Boreal forests are important global carbon (C) sinks and, therefore, considered as a key element in climate change mitigation policies. However, their actual C sink strength is uncertain and under debate, particularly for the actively managed forests in the boreal regions of Fennoscandia. In this study, we use an extensive set of biometric-and chamber-based C flux data collected in 50 forest stands (ranging from 5 to 211 years) over 3 years (2016–2018) with the aim to explore the variations of the annual net ecosystem production (NEP; i.e., the ecosystem C balance) across a 68 km2 managed boreal forest landscape in northern Sweden. Our results demonstrate that net primary production rather than heterotrophic respiration regulated the spatio-temporal variations of NEP across the heterogeneous mosaic of the managed boreal forest landscape. We further find divergent successional patterns of NEP in our managed forests relative to naturally regenerating boreal forests, including (i) a fast recovery of the C sink function within the first decade after harvest due to the rapid establishment of a productive understory layer and (ii) a sustained C sink in old stands (131–211 years). We estimate that the rotation period for optimum C sequestration extends to 138 years, which over multiple rotations results in a long-term C sequestration rate of 86.5 t C ha−1 per rotation. Our study highlights the potential of forest management to maximize C sequestration of boreal forest landscapes and associate climate change mitigation effects by developing strategies that optimize tree biomass production rather than heterotrophic soil C emissions. [ABSTRACT FROM AUTHOR]

This study examines the effects of supplying forest biomass on forest ecosystem services and goods with a dynamic systems model. This unique analysis models dynamic trade and investments in forestry, thereby capturing price changes from increased forest biomass demand on current and future flows of forest ecosystem services and natural capital stocks. Forests across the globe are interconnected through timber and forest biomass markets, which influence forest management decisions, land rents, and policy responses. Results indicate that expanding forest biomass consumption, even at relatively low levels, will have important impacts on ecosystem services, particularly the benefits of terrestrial carbon sequestration and timber outputs. Increased forest biomass production can be achieved with smaller impacts on ecosystem services through policies targeting natural forest preservation. However, policies that encourage residual biomass use for energy or discourage forest plantation expansion could potentially compromise carbon benefits. [ABSTRACT FROM AUTHOR]

By 2050 Nepal has committed to having net zero-CO2 emissions, and therefore, there is a need for improved effort to assess C accounting in energy, industry, and forestry sectors. Forests are critical to the global C cycle because they store large amounts of atmospheric C in biomass and soil. The estimation of the C sequestration potential of any forest is crucial since it significantly contributes to the mitigation of global climate change. In this context, we estimated the biomass and C sequestration on two contrasting aspects of Pinus roxburghii-Sarg forest in Daman hill in Makawanpur district, Nepal. The study found that tree density of 210 per ha in the southern aspect, while in the northern, it was found 180 per ha. Tree biomass estimated on the southern aspect was 434.68 t ha-1 and 426.16 t ha-1 on the north. Accordingly, on the southern forest, C stock was found to 204.30 t ha-1 as compared to 200.32 t ha-1 on the north. Both biomass increment and C sequestration rate was found to be higher on the southern aspect than the north. The study suggests that dbh classes, and aspects factors play a crucial role in biomass and C sequestration. P. roxburghii forests are important C sinks because of their capacity to store large amounts of C in biomass. Thus, conservation and sustainable management of these native forest ecosystems are suggested. [ABSTRACT FROM AUTHOR]

Nature‐based climate solutions are a vital component of many climate mitigation strategies, including California's, which aims to achieve carbon neutrality by 2045. Most carbon offsets in California's cap‐and‐trade program come from improved forest management (IFM) projects. Since 2012, various landowners have set up IFM projects following the California Air Resources Board's IFM protocol. As many of these projects approach their 10th year, we now have the opportunity to assess their effectiveness, identify best practices, and suggest improvements toward future protocol revisions. In this study, we used remote sensing‐based datasets to evaluate the carbon trends and harvest histories of 37 IFM projects in California. Despite some current limitations and biases, these datasets can be used to quantify carbon accumulation and harvest rates in offset project lands relative to nearby similar "control" lands before and after the projects began. Five lines of evidence suggest that the carbon accumulated in offset projects to date has generally not been additional to what might have otherwise occurred: (1) most forests in northwestern California have been accumulating carbon since at least the mid‐1980s and continue to accumulate carbon, whether enrolled in offset projects or not; (2) harvest rates were high in large timber company project lands before IFM initiation, suggesting they are earning carbon credits for forests in recovery; (3) projects are often located on lands with higher densities of low‐timber‐value species; (4) carbon accumulation rates have not yet increased on lands that enroll as offset projects, relative to their pre‐enrollment levels; and (5) harvest rates have not decreased on most project lands since offset project initiation. These patterns suggest that the current protocol should be improved to robustly measure and reward additionality. In general, our framework of geospatial analyses offers an important and independent means to evaluate the effectiveness of the carbon offsets program, especially as these data products continue improving and as offsets receive attention as a climate mitigation strategy. [ABSTRACT FROM AUTHOR]

Climate change mitigation trade-offs between increasing harvests to exploit substitution effects versus accumulating forest carbon sequestration complicate recommendations for climate beneficial forest management. Here, a time dynamic assessment ascertains climate change mitigation potential from different rotation forest management alternatives across three Swedish regions integrating the forest decision support system Heureka RegWise with a wood product model using life cycle assessment data. The objective is to increase understanding on the climate effects of varying the forest management. Across all regions, prolonging rotations by 20% leads on average to the largest additional net climate benefit until 2050 in both, saved emissions and temperature cooling, while decreasing harvests by 20% leads to the cumulatively largest net climate benefits past 2050. In contrast, increasing harvests or decreasing the rotation period accordingly provokes temporally alternating net emissions, or slight net emission, respectively, regardless of a changing market displacement factor. However, future forest calamities might compromise potential additional temperature cooling from forests, while substitution effects, despite probable prospective decreases, require additional thorough and time explicit assessments, to provide more robust policy consultation. [ABSTRACT FROM AUTHOR]

Climate change requires mitigation actions, mainly preventive, by reducing greenhouse gas emissions; however, carbon sequestration is a complementary measure. Although short-term carbon sequestration can be somewhat effective, it is really interesting when it is permanent. Sequestration calculates the carbon removed from the atmosphere over a period, while the stock expresses the cumulative carbon of a forest. Sequestration and stock are closely related, but ecosystem service valuation often focuses on the former, which can discourage forest maintenance. This study analyzes carbon sequestration and storage in four pine forests located in central Spain, comparing its valuation for different equivalence times, a period considered sufficient to compensate for the emission of one ton of CO2 into the atmosphere. Equilibrium equivalence times were calculated for each forest, defined as the period in which carbon sequestration and stock payments are equal; values ranged from 33 to 101 years, with significant correlations with commercial volume and carbon stock. Equivalence times of 30–50 years are reasonable in Mediterranean forest stands with moderate growth and density, while in dense mature stands this time should increase to 50–100 years. Valuing carbon stocks and paying for them in a sustained manner over time promotes sustainable forest management, while the sale of sequestration credits may generate a speculative "greenwashing" market. In addition, payments for stocks can be applied to any forest stand and not only to new plantations. Carbon stock valuation is a win–win strategy for climate change mitigation, sustainable forest management, and rural development. [ABSTRACT FROM AUTHOR]

Background: Forestry plays a major role in climate change mitigation. However, which intensity of logging is best suited for that task remains controversial. We contribute to the debate by quantitatively analyzing three different forest management scenarios in Germany—a baseline scenario which represents a continuation of current forest management practice as well as an intensive and an extensive logging scenario. We assess whether increased carbon storage in wood products and substitution of other emission-intensive materials can offset reduced carbon stocks in the forest due to increased harvesting. For that, we calculate annual required displacement factors (RDF)—a dimensionless quantity that indicates the minimal displacement factor (DF) so that intensive forestry outperforms extensive forestry from a climate perspective. Results: If the intensive forest management scenario is included in the comparison, the RDF starts off with relatively high values (1 to 1.5) but declines over time and eventually even reaches negative values. Comparing the extensive scenario to a baseline yields RDF values between 0.1 and 0.9 with a slightly increasing trend. Compared to RDFs, expected future DFs are too low to favour the intensive forestry scenario and too high to favour the extensive forestry scenario, during the first 25 years of the modeling period. However, towards the end of the modeling period, the relationship between DFs and RDF is turned around in both comparisons. In the comparison between intensive and extensive forest management RDF values are very similar to future DF trajectories. Conclusion: RDFs are a useful tool for comparing annual climate impacts of forest growth scenarios and can be used to benchmark material and energy substitution effects of wood. Our results indicate that the baseline scenario reflects an effective compromise between carbon stocks in the forest and carbon displacement by wood use. For a longer modeling period, however, this might not be the case. Which of the alternative scenarios would be best suited for climate change mitigation is heavily dependent on future DF trajectory. Hence, our findings highlight the necessity of robust projections of forest dynamics and industry decarbonization pathways. [ABSTRACT FROM AUTHOR]

Great hope is being placed in the ability of forest ecosystems to contribute to greenhouse gas (GHG) emission reduction targets to limit global warming. Many nations plan to rely on forest-based climate mitigation activities to create additional and long-term carbon sequestration. Here, we take a critical look at the state of the policy and ecology surrounding forest-based natural climate solutions (NCS), with a focus on temperate forests of the United States (US). We first provide a high-level overview of carbon accounting, including key concepts used in the monitoring, reporting and verification of forest-based NCS. Second, we provide a high-level overview of forest carbon dynamics, including pools and fluxes, and drivers of their change. We then identify gaps in the current systems of GHG accounting, and between current ambitions and basic forest ecology. Improved use of data in models provides a path forward to better assessment and anticipation of forest-based climate mitigation. We illustrate this with the creation of a climate-sensitive forestry model, using tree-ring time series data. This climate-sensitive forest simulator will improve planning of site-level climate mitigation activities in the US by providing more realistic expectations of the carbon sequestration potential of forests undergoing climate change. Our review highlights the sobering complexity and uncertainty surrounding forest carbon dynamics, along with the need to improve carbon accounting. If we are to expect forests to play the significant emissions reduction role that is currently planned, we should view immediate emissions reductions as critical to preserve the climate mitigation capacity of forest ecosystems. [ABSTRACT FROM AUTHOR]

Fossil‐based emissions can be avoided by using wood in place of non‐renewable raw materials as energy and materials. However, wood harvest influences forest carbon stocks. Increased harvest may reduce the overall climate benefit of wood use significantly, but is widely overlooked. We reviewed selected simulation studies and compared differences in forest carbon and amount of wood harvested between harvest scenarios of different intensities for three different time perspectives: short‐ (1–30 years), mid‐ (31–70 years), and long‐term (71–100 years). Out of more than 450 reviewed studies 45 provided adequate data. Our results show that increased harvest reduces carbon stocks over 100 years in temperate and boreal forests by about 1.6 (stdev 0.9) tC per tC harvested (referred to as carbon balance indicator (CBI)). CBI proved to be robust when outliers explicitly influenced by factors other than changes in the harvest rate, such as fertilization or increase in forest area, were removed. The carbon impacts tend to be greatest in the mid‐term, but no significant difference in was found for average values between short and long time‐horizons. CBI can be interpreted as carbon opportunity costs of wood harvest in forests. Our results indicate that even after 100 years, CBI is significant compared to the typical GHG credits expected in the technosphere by avoiding fossil emissions in substitution and increasing carbon stocks in harvested wood products. Our estimates provide typical values that can directly be included in GHG balances of products or assessments of mitigation policies and measures related to wood use. However, more systematic scenarios with transparent information on influencing factors for forest carbon stocks are required to provide better constrained estimates for specific forest types. [ABSTRACT FROM AUTHOR]

Boreal forests are often managed to maximize wood production, but other goals, among which climate change mitigation, are increasingly important. Hence, it is necessary to examine synergies and trade-offs between forest production and its potential for carbon sequestration and climate change mitigation in forest stands. To this aim, we develop a novel mass-balanced process-based compartmental model that allows following the carbon path from its photosynthetic fixation until its return to the atmosphere by autotrophic or heterotrophic respiration, or by being burnt as wood product. Following carbon in the system allows to account for how long forest ecosystems and wood products retain carbon away from the atmosphere (i.e., the carbon transit time). As example, we apply the model to four management scenarios, i.e., mixed-aged pine, even-aged pine, even-aged spruce, and even-aged mixed forest, and contrast metrics of performance relative to wood production, carbon sequestration, and climate change mitigation potential. While at the end of an 80 yr rotation the even-aged forests held up to 31% more carbon than the mixed-aged forest, the mixed-aged forest was superior during almost the entire rotation when factoring in the carbon retention time away from the atmosphere, i.e., in terms of climate change mitigation potential. Importantly, scenarios that maximize production or amount of carbon stored in the ecosystems are not necessarily the most beneficial for carbon retention away from the atmosphere. These results underline the importance of considering carbon transit time when evaluating forest management options for potential climate change mitigation. [Display omitted] • We evaluate wood production and climate change mitigation potential of boreal forests. • We combine an ecophysiological growth model with forest inventory tree allometries. • Higher carbon sequestration does not ensure higher climate change mitigation potential. • Potential climate change mitigation depends on carbon time away from the atmosphere. [ABSTRACT FROM AUTHOR]

We analyse the short‐ and long‐term consequences for atmospheric greenhouse gas (GHG) concentrations of forest management strategies and forest product uses in Sweden by comparing the modelled consequences of forest resource use vs. increased conservation at different levels of GHG savings from carbon sequestration and product substitution with bioenergy and other forest products. Increased forest set‐asides for conservation resulted in larger GHG reductions only in the short term and only when substitution effects were low. In all other cases, forest use was more beneficial. In all scenarios, annual carbon dioxide (CO2) sequestration rates declined in conservation forests as they mature, eventually approaching a steady state. Forest set‐asides are thus associated with increasing opportunity costs corresponding to foregone wood production and associated mitigation losses. Substitution and sequestration rates under all other forest management strategies rise, providing support for sustained harvest and cumulative mitigation gains. The impact of increased fertilization was everywhere beneficial to the climate and surpassed the mitigation potential of the other scenarios. Climate change can have large—positive or negative—influence on outcomes. Despite uncertainties, the results indicate potentially large benefits from forest use for wood production. These benefits, however, are not clearly linked with forestry in UNFCCC reporting, and the European Union's Land Use, Land‐Use Change and Forestry carbon accounting, framework may even prevent their full realization. These reporting and accounting frameworks may further have the consequence of encouraging land set‐asides and reduced forest use at the expense of future biomass production. Further, carbon leakage and resulting biodiversity impacts due to increased use of more GHG‐intensive products, including imported products associated with deforestation and land degradation, are inadequately assessed. Considerable opportunity to better mobilize the climate change mitigation potential of Swedish forests therefore remains. [ABSTRACT FROM AUTHOR]

Biochar (BC) is often proposed as a tool for climate change mitigation, due to the expected long lifetime in the environment. However, BC's stability can vary depending on feedstock type and the presence of labile carbon fractions. In this study, we verify the recent methods with new possible tools for biochar stability assessment on six different biochars derived from commonly available Europe biomass sources. Elemental composition (CHNO), dissolved organic carbon (DOC) and water-soluble carbonates content (WSC), volatile organic compounds (VOCs) composition, and mid-infrared spectra (MIR) were performed to estimate the persistence of biochars. Under similar conditions of pyrolysis, biochar properties can vary depending on a feedstock origin. Less aromatic structure and higher contents of labile carbon fractions (DOCs and WSC) in food waste biochars affected the lower stability, while biochars derived from high lignocellulose materials (straw, wood, and grass) were strongly carbonized, with persistent, aromatic structure. Labile carbon pool content (DOC, WSC) and spectral analysis can be useful tools for biochar stability assessment, giving similar information to the standard molar ratio method. Biochars obtained from agriculture and forestry management biomass should be considered as highly stable in soil and are appropriate for long-term carbon sequestration purposes. [ABSTRACT FROM AUTHOR]

Constraining the climate crisis requires urgent action to reduce anthropogenic emissions while simultaneously removing carbon dioxide from the atmosphere. Improved information about the maximum magnitude and spatial distribution of opportunities for additional land-based removals of CO2 is needed to guide on-the-ground decisionmaking about where to implement climate change mitigation strategies. Here, we present a globally consistent spatial dataset (approximately 500-m resolution) of current, potential, and unrealized potential carbon storage in woody plant biomass and soil organic matter. We also provide a framework for prioritizing actions related to the restoration, management, and maintenance of woody carbon stocks and associated soils. By comparing current to potential carbon storage, while excluding areas critical to food production and human habitation, we find 287 petagrams (PgC) of unrealized potential storage opportunity, of which 78% (224 PgC) is in biomass and 22% (63 PgC) is in soil. Improved management of existing forests may offer nearly three-fourths (206 PgC) of the total unrealized potential, with the majority (71%) concentrated in tropical ecosystems. However, climate change is a source of considerable uncertainty. While additional research is needed to understand the impact of natural disturbances and biophysical feedbacks, we project that the potential for additional carbon storage in woody biomass will increase (+17%) by 2050 despite projected decreases (212%) in the tropics. Our results establish an absolute reference point and conceptual framework for national and jurisdictional prioritization of locations and actions to increase land-based carbon storage. [ABSTRACT FROM AUTHOR]

During 2010-2013, we investigated the effects of stump harvesting on greenhouse gas (GHG) fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) with the flux-gradient technique at four experimental plots in a hemiboreal forest in Sweden. All plots were clear-cut and soil scarified and two of the plots were additionally stump harvested. The two clear-cut plots served as control plots. Due to differences in topography, we had one wetter and one drier plot of each treatment. All plots exhibited substantial emissions of GHGs and we noted significant effects of wetness on CO2, CH4 and N2O fluxes within treatments and significant effects of stump harvesting on CO2 and N2O fluxes at the dry plots. The CO2 emissions were lower at the dry stump harvested plot than at the dry control, but when estimated emissions from the removed stumps were added, total CO2 emissions were higher at the stump harvested plot, indicating a small enhancement of soil respiration. In addition, we noted significant emissions of N2O at this plot. At the wet plots, CO2 emissions were higher at the stump harvested plot, also suggesting a treatment effect but differences in wetness and vegetation cover at these plots make this effect more uncertain. At the wet plots, we noted sustained periods (weeks to months) of net N2O uptake. During the year with simultaneous measurements of the abovementioned GHGs, GHG budgets were 1.224×103 and 1.442×10³ gm-2 of CO2-equivalents at the wet and dry stump harvested plots, respectively, and 1.070×103 and 1.696×10³ gm-2 of CO2-equivalents at the wet and dry control plots, respectively. CO2 fluxes dominated GHG budgets at all plots but N2O contributed with 17% at the dry stump harvested plot. For the full period 2010-2013, total carbon (CO2+CH4) budgets were 4.301×103 and 4.114×103 g m-2 of CO2-eqvivalents at the wet and dry stump harvest plots, respectively and 4.107×10³ and 5.274×10³ gm-2 of CO2-equivalents at the wet and dry control plots, respectively. Our results support recent studies suggesting that stump harvesting does not result in substantial increase in CO2 emissions but uncertainties regarding GHG fluxes (especially N2O) remain and more long-term measurements are needed before robust conclusions can be drawn. [ABSTRACT FROM AUTHOR]

Background: Forests are atmospheric carbon sinks, whose natural growth can contribute to climate change mitigation. However, they are also affected by climate change and various other phenomena, for example, the low growth of coniferous forests currently reported globally, including in the Republic of Korea. In response to the implementation of the Paris Agreement, the Korean government has proposed 2030 greenhouse gas roadmap to achieve a Nationally Determined Contribution (NDC), and the forest sector set a sequestration target of 26 million tons by 2030. In this study, the Korean forest growth model (KO-G-Dynamic model) was used to analyze various climate change and forest management scenarios and their capacity to address the NDC targets. A 2050 climate change adaptation strategy is suggested based on forest growth and CO2 sequestration. Results: Forest growth was predicted to gradually decline, and CO2 sequestration was predicted to reach 23 million tons per year in 2050 if current climate and conditions are maintained. According to the model, sequestrations of 33 million tCO2 year−1 in 2030 and 27 million tCO2 year−1 in 2050 can be achieved if ideal forest management is implemented. It was also estimated that the current forest management budget of 317 billion KRW (264 million USD) should be twice as large at 722 billion KRW (602 million USD) in the 2030s and 618 billion KRW (516 million USD) in the 2050s to achieve NDC targets. Conclusions: The growth trend in Korea's forests transitions from young-matured stands to over-mature forests. The presented model-based forest management plans are an appropriate response and can increase the capacity of Korea to achieve its NDC targets. Such a modeling can help the forestry sector develop plans and policies for climate change adaptation. [ABSTRACT FROM AUTHOR]

For millennia, forest ecosystems in California have been shaped by fire from both natural processes and Indigenous land management, but the notion of climatic variation as a primary controller of the pre-colonial landscape remains pervasive. Understanding the relative influence of climate and Indigenous burning on the fire regime is key because contemporary forest policy and management are informed by historical baselines. This need is particularly acute in California, where 20th-century fire suppression, coupled with a warming climate, has caused forest densification and increasingly large wildfires that threaten forest ecosystem integrity and management of the forests as part of climate mitigation efforts. We examine climatic versus anthropogenic influence on forest conditions over 3 millennia in the western Klamath Mountains—the ancestral territories of the Karuk and Yurok Tribes—by combining paleoenvironmental data with Western and Indigenous knowledge. A fire regime consisting of tribal burning practices and lightning were associated with long-term stability of forest biomass. Before EuroAmerican colonization, the long-term median forest biomass was between 104 and 128 Mg/ha, compared to values over 250 Mg/ha today. Indigenous depopulation after AD 1800, coupled with 20th-century fire suppression, likely allowed biomass to increase, culminating in the current landscape: a closed Douglas fir–dominant forest unlike any seen in the preceding 3,000 y. These findings are consistent with precontact forest conditions being influenced by Indigenous land management and suggest large-scale interventions could be needed to return to historic forest biomass levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alpine study sites with a long close-to-nature forestry (CNF) history were studied. • Alternative climate change and CNF management scenarios were simulated. • CNF performs well in ensuring multiple forest ecosystem services and biodiversity. • Climate change requires adaptation of CNF by fostering climate-adapted tree species. • High multifunctionality, including biodiversity, needs diversified management. Close-to-nature forestry (CNF) has a long tradition in European Alpine forest management, playing a crucial role in ensuring the continuous provision of biodiversity and forest ecosystem services, including protection against natural hazards. However, climate change is causing huge uncertainties about the future applicability of CNF in the Alpine region. The question arises as to whether current CNF practices are still suitable for adapting forests to climate change impacts while also meeting the increasing societal demands regarding Alpine forests, including their potential contribution to climate change mitigation. To answer this question, we simulated forest development using the ForClim forest model at two Alpine study sites, together representing a large biogeographic gradient from high-elevation inner Alpine forests (Switzerland) to lower-elevation south-eastern Alpine forests (Slovenia). The simulations considered three climate scenarios (historical climate, SSP2-4.5 and SSP5-8.5) and six alternative management strategies, including both current CNF management practices and climate-adapted versions. Using an indicator based multi-criteria decision analysis framework, we assessed the joint impacts of climate and management on biodiversity and key ecosystem services of the investigated regions, including carbon sequestration (CS) inside and outside the forest ecosystem boundary. The joint effects of climate change and CNF varied, both among and within the study sites along the biogeographical gradient. While CS was more resistant to climate change under current CNF at the south-eastern Alpine site, it was more sensitive at the inner Alpine site, where CS potentials decreased at lower elevations. This adverse effect could be partly mitigated by fostering the use of climate-adapted tree species. However, current CNF and adaptations of it did not meet multiple management objectives equally well: while protection from gravitation hazards and timber production also benefited from this silvicultural practice, biodiversity benefited from CNF variants with low-intensity or no management. In conclusion, CNF has a high potential to continue fulfilling its crucial role in European Alpine forests. A differentiated approach will be needed in the future, however, to identify forest stands where adaptive measures are required, especially at sites particularly vulnerable to climate change. In combination with less intensively managed or unmanaged areas, CNF provides a management portfolio that will help European Alpine forests to meet the demands of future society. [ABSTRACT FROM AUTHOR]

• The nexus between forest-based climate mitigation and health is poorly researched. • This scoping review identified exposure pathways and health co-benefits from forests. • There is potential for synergies between forest management and health benefits. • Interdisciplinary efforts are required for advancement of research and understanding. Climate change is a pressing global challenge with profound implications for human health. Forest-based climate change mitigation strategies, such as afforestation, reforestation, and sustainable forest management, offer promising solutions to mitigate climate change and simultaneously yield substantial co-benefits for human health. The objective of this scoping review was to examine research trends related to the interdisciplinary nexus between forests as carbon sinks and human health co-benefits. We developed a conceptual framework model, supporting the inclusion of exposure pathways, such as recreational opportunities or aesthetic experiences, in the co-benefit context. We used a scoping review methodology to identify the proportion of European research on forest-based mitigation strategies that acknowledge the interconnection between mitigation strategies and human impacts. We also aimed to assess whether synergies and trade-offs between forest-based carbon sink capacity and human co-benefits has been analysed and quantified. From the initial 4,062 records retrieved, 349 reports analysed European forest management principles and factors related to climate change mitigation capacity. Of those, 97 studies acknowledged human co-benefits and 13 studies quantified the impacts on exposure pathways or health co-benefits and were included for full review. Our analysis demonstrates that there is potential for synergies related to optimising carbon sink capacity together with human co-benefits, but there is currently a lack of holistic research approaches assessing these interrelationships. We suggest enhanced interdisciplinary efforts, using for example multideterminant modelling approaches, to advance evidence and understanding of the forest and health nexus in the context of climate change mitigation. [ABSTRACT FROM AUTHOR]

• Substitution factors for forest products for the Canadian context were developed. • Substitution factors ranging from 0.51 to 0.91 tC/tC were found. • They will lead to more accurate assessments of the forest GHG mitigation potential. • These factors will help governments to manage forest and fight climate change. Evaluating the climate change mitigation potential of the forest sector requires a holistic approach based on forest carbon (C) sequestration, C storage in harvested wood products (HWP) and substitution on markets. High uncertainty is associated with substitution factors, that express avoided fossil greenhouse gas (GHG) emissions from the use of forest-based products in replacement of GHG-intensive materials and fossil fuels. Few studies have focused on the development of substitution factors in Canada, resulting in the use of unrepresentative generic data. Here, we provide a framework to reduce uncertainties related to substitution factors for primary wood products in a Canadian context. A life cycle assessment framework is used to quantify fossil GHG emissions for a baseline and a wood-intensive scenario. For solid product substitution, we focused on the construction sector and analyzed a range of innovative wood buildings with steel and reinforced concrete as alternative materials. We found non-weighted averages of 0.80 tC/tC for sawnwood and 0.81 tC/tC for panels. For energy substitution, we analyzed cases with different specifications on biomass product, facility type and alternative fossil fuel source in non-residential heat production and biofuel transportation sectors. We found a non-weighted average of 0.80 tC/tC for non-residential heat production and 0.51 tC/tC for biofuel transportation, that can be interpreted as 0.91 tC/tC for heavy fuel oil, 0.69 tC/tC for light fuel oil and 0.68 tC/tC for natural gas substitution. These results provide a benchmark for substitution factors in Canada, to help guide forest management strategies for climate change mitigation. [ABSTRACT FROM AUTHOR]

Temporary carbon storage and substitution benefits of harvested wood products (HWPs) aid in mitigating global warming. However, the extent of this effect remains unclear. Current studies typically rely on a simple summation of the annual carbon sink. This method overlooks the fact that, due to radiative forcing delay, each ton of carbon sequestered has an impact on global warming, which dynamically changes year by year. Such an oversight could lead to an underestimation of HWPs' contribution to global warming mitigation. This study focused on a forestry resource-based city in Northeast China and utilized the Carbon Budget Model for the Canadian Forest Sector (CBM-CFS3) and dynamic life cycle assessment (DLCA) to quantify the dynamic global warming impact (DGWI) of forestry biogenic carbon. The results indicate that: 1) From 2020 to 2120, the maximum DGWI could reach −42.70 Mt CO 2 e. Enhancing the collection and utilization of harvesting residues and promoting products with longer lifespans and higher substitution potential can further increase these benefits. 2) The DLCA method, integrating substitution effects, offers a more precise evaluation of forestry's climate mitigation benefits. Across all scenarios and periods in this study, HWPs' contribution to mitigating global warming, as calculated by the DLCA method, exceeds that estimated by the simple carbon sink summation method by 7.70 %–560.72 %. These findings help to delve deeper into the role of forests in emission reduction and carbon sequestration, providing important references for achieving sustainable forestry management. • Developing and strategically using HWPs positively impacts global warming mitigation. • Method of simply summing up carbon sinks undervalues HWPs' cumulative climate impact. • DLCA method helps assess dynamic global warming impact of forestry biogenic carbon. • Forest management should balance wood production and climate mitigation. [ABSTRACT FROM AUTHOR]

• Most of the NbS of Tropical drylands of India are not follow the IUCN standard criteria. • The Identified NbS are baised towards environmental services than addressing social needs of the people. • Improved NbS interventions requires intensive enagement of stakeholders for addressing social causes. Nature-based Solutions (NbS) is a flexible, adaptable, and multi-functional strategies employed to address climate change. However, all the claimed NbS are actually do not adhere the criteria of being NbS. Therefore, present study analysed 87 articles to appraise adherence of potential NbS as per the IUCN Global Standard, along with evaluation of flow of associated ecosystem services (ES). The review identified 39 interventions, out of which only twelve interventions adhered the criteria of NbS. Among the classified NbS, two interventions, namely, sustainable forest management (SFM) (80.83%) and haveli rejuvenation (75.61%) strongly adhered to the IUCN Standard. Lack of adherence in the non-classified NbS interventions was mainly attributed to absence of information on inclusive governance, monitoring and associated trade-offs. The identified 39 interventions were also observed to be enhancing a total of 37 ES, evaluated through 37 distinct indicators i.e. different and enhanced flow of ES were observed by the different NbS. However, the majority of classified NbS were biased towards flow of environmental services than social services. Present study results that all claimed NbS cannot fulfilled the intended objectives of NbS and thus cannot be classified under the NbS as per global standard. Moreover, assessing the flow of associated ES may be an additional support to broaden the scope of NbS implementation. Therefore, present study also highlights to integrate the flow of ES along with the adherence criteria of NbS. Moreover, the review also facilitate to understand constraints associated with the implementation of potential NbS interventions and thus, suggests considering wider aspects in the future researches for assessing the implementation of NbS. [ABSTRACT FROM AUTHOR]

With 20% of the world's forests, Russia has global potential in bioeconomy development, biodiversity conservation and climate change mitigation. However, unsustainable forest management based on 'wood mining' reduces this potential. Based on document analysis, participant observations and interviews, this article shows how non-state actors—environmental NGOs and forest companies—address forest resource depletion and primary forest loss in Russia. We analyse two key interrelated forest discourses driven by non-state actors in Russia: (1) intensive forest management in secondary forests as a pathway towards sustained yield and primary forest conservation; (2) intact forest landscapes as a priority in primary forest conservation. We illustrate how these discourses have been integrated into policy debates, institutions and practices and discuss their relation to relevant global discourses. The article concludes that despite successful cases in conserving intact forest landscapes, there is still a frontier between sustainable forest management discourses and forestry practice in Russia. [ABSTRACT FROM AUTHOR]

Forests are subject to a huge variety of often competing socio-economic demands and environmental change. This paper assesses the related conflicts that occur along what we label to be a "Global Forest Environmental Frontier". Assessing 11 contributions to a special issue on the same topic, it summarizes the main contents of these papers and concludes with an assessment of major trends. The contributions to the special issue take both a regional and topic-related approach, assessing forest environmental conflicts on all five forested continents and investigating issues such as forest biodiversity conservation, climate change adaptation and mitigation, environmental justice and equity, development, and forest management and conservation discourses. Taken together, they provide an overview on the multiple facets of the Global Forest Environmental Frontier, but also identify some shared patterns and trajectories, which are outlined at the end of this paper. [ABSTRACT FROM AUTHOR]

Biomass procured from forests affected by natural disturbances as a bioenergy source is increasingly considered in the context of climate change mitigation. By comparing clearcuts with and without biomass procurement, we aimed to determine the effects of biomass extraction performed alongside lumber harvesting on regeneration density, number of planting microsites, forest renewal costs, and carbon fluxes, in harvested boreal stands affected by spruce budworm. The results showed that biomass procurement increased regeneration density and number of planting microsites. Reduction of downed woody debris due to biomass procurement lowered site preparation costs by 282.07 $CAN·ha−1, equivalent to 14.45 $CAN per oven-dry metric ton (odmt−1) of harvested biomass. Product value from biomass processing had to reach from 13.90 to 76.84 $CAN·odmt−1 to make biomass procurement operations profitable. Since biomass procurement significantly increased stocking and reduced the amount of decaying debris, it also reduced cumulative CO2 emissions relative to scenarios without biomass procurement. However, ensuring forest renewal through site preparation and plantation per se, irrespective of biomass procurement, played a more important role for carbon sequestration and net balance. Integrating biomass harvesting with silviculture could have significant ecological and financial impacts on forest management while supporting mitigation efforts against climate change. [ABSTRACT FROM AUTHOR]

Forests provide a wide range of provisioning, regulating and cultural services of great value to societies across the Mediterranean basin. In this study, we reviewed the scientific literature of the last 30 years to quantify the magnitude of projected changes in ecosystem services provision by Mediterranean forests under IPCC climate change scenarios. We classified the scenarios according to the temperature threshold of 2℃ set by the Paris Agreement (below or above). The review of 78 studies shows that climate change will lead to a general reduction in the provision of regulating services (e.g. carbon storage, regulation of freshwater quantity and quality) and a general increase in the number of fires, burnt areas and generally, an increase in climate‐related forest hazards (median + 62% by 2100). Studies using scenarios above the 2℃ threshold projected significantly more negative changes in regulating services than studies using scenarios below this threshold. Main projected trend changes on material services (e.g. wood products), were less clear and depended on (i) whether or not the studies considered the interaction between the rise in temperatures and other drivers (e.g. forest management, CO2 fertilization) and (ii) differences in productivity responses across the tree species evaluated. Overall, the reviewed studies projected significant reductions in range extent and habitat suitability for the most drought‐sensitive forest species (e.g. −88% Fagus sylvatica), while the amount of habitat available for more drought‐tolerant species will remain stable or increase; however, the magnitude of projected change for these more xeric species was limited when high‐end extreme climatic scenarios were considered (above Paris Agreement). Our review highlights the benefits that climate change mitigation (to keep global mean temperature increase <2℃) can bring in terms of service provision and conservation of Mediterranean forests. [ABSTRACT FROM AUTHOR]

The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy‐making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system‐level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short‐term emissions reduction targets can lead to decisions that make medium‐ to long‐term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy. [ABSTRACT FROM AUTHOR]

Background: The contribution of EU forests to climate change mitigation in 2021–2025 is assessed through the Forest Reference Levels (FRLs). The FRL is a projected country-level benchmark of net greenhouse gas emissions against which the future net emissions will be compared. The FRL models the hypothetical development of EU forest carbon sink if the historical management practices were continued, taking into account age dynamics. The Member States' FRLs have been recently adopted by the European Commission with the delegated Regulation (EU) 2021/268 amending the Regulation (EU) 2018/841. Considering the complexity of interactions between forest growth, management and carbon fluxes, there is a need to understand uncertainties linked to the FRL determination. Results: We assessed the methodologies behind the modelled FRLs and evaluated the foreseen impact of continuation of management practices and age dynamics on the near-future EU27 + UK forest carbon sink. Most of the countries implemented robust modelling approaches for simulating management practices and age dynamics within the FRL framework, but faced several challenges in ensuring consistency with historical estimates. We discuss that the projected 16% increase in harvest in 2021–2025 compared to 2000–2009, mostly attributed to age dynamics, is associated to a decline of 18% of forest sink (26% for living biomass only). Conclusions: We conclude that the FRL exercise was challenging but improved the modelling capacity and data availability at country scale. The present study contributes to increase the transparency of the implementation of forest-related EU policies and provides evidence-based support to future policy development. [ABSTRACT FROM AUTHOR]

The effectiveness of land-based climate mitigation strategies is generally estimated on a case-by-case basis without considering interactions with other strategies or influencing factors. Here we evaluate a new, comprehensive approach that incorporates interactions among multiple management strategies, land use/cover change, wildfire, and climate, although the potential effects of climate change are not evaluated in this study. The California natural and working lands carbon and greenhouse gas model (CALAND) indicates that summing individual practice estimates of greenhouse gas impacts may underestimate emission reduction benefits in comparison with an integrated estimate. Annual per-area estimates of the potential impact of specific management practices on landscape emissions can vary based on the estimation period, which can be problematic for extrapolating such estimates over space and time. Furthermore, the actual area of implementation is a primary factor in determining potential impacts of management on landscape emissions. Nonetheless, less intensive forest management, avoided conversion to urban land, and urban forest expansion generally create the largest annual per-area reductions, while meadow restoration and forest fuel reduction and harvest practices generally create the largest increases with respect to no management. CALAND also shows that data uncertainty is too high to determine whether California land is a source or a sink of carbon emissions, but that estimating effects of management with respect to a baseline provides valid results. Important sources of this uncertainty are initial carbon density, net ecosystem carbon accumulation rates, and land use/cover change data. The appropriate choice of baseline is critical for generating valid results. [ABSTRACT FROM AUTHOR]

Net primary productivity (NPP) and net ecosystem production (NEP) are often used interchangeably, as their difference, heterotrophic respiration (soil heterotrophic CO2 efflux, RSH = NPP−NEP), is assumed a near‐fixed fraction of NPP. Here, we show, using a range‐wide replicated experimental study in loblolly pine (Pinus taeda) plantations that RSH responds differently than NPP to fertilization and drought treatments, leading to the divergent responses of NPP and NEP. Across the natural range of the species, the moderate responses of NPP (+11%) and RSH (−7%) to fertilization combined such that NEP increased nearly threefold in ambient control and 43% under drought treatment. A 13% decline in RSH under drought led to a 26% increase in NEP while NPP was unaltered. Such drought benefit for carbon sequestration was nearly twofold in control, but disappeared under fertilization. Carbon sequestration efficiency, NEP:NPP, varied twofold among sites, and increased up to threefold under both drought and fertilization. Plain Language Summary: Two metrics of ecosystem productivity—vegetation biomass accumulation (net primary production, NPP) and net ecosystem carbon gain (NEP)—are often used interchangeably, as their difference, heterotrophic respiration, is assumed a relatively constant fraction of the former. Here, we show that soil heterotrophic respiration responds to water availability (a major climate change variable) and nutrient availability (a major management factor) differently than does NPP, leading to the divergence of NPP and NEP responses to water and nutrient availability. Key Points: Suppressed heterotrophic respiration by drought and fertilization amplified carbon sequestration responses compared to those in productivityCarbon sequestration efficiency increased up to threefold under both drought and fertilizationTrade‐off between biomass production and carbon sequestration has implications for forest management for climate mitigation purposes [ABSTRACT FROM AUTHOR]