The Gordian knot of mangrove conservation: Disentangling the role of scale,services and benefits

Mangrove forests are among the most threatened tropical ecosystems. Their role as providers of important ecosystem services such as coastal protection, carbon storage and nursery habitats for economically important species is increasingly acknowledged. But mangrove destruction continues, and we might have to face the prospect of a world deprived of the services offered by mangrove ecosystems. Mangrove transformation and destruction is often caused by mismatches in mangrove system management. These root in interests that focus on selected ecosystem services only, but also result from a problem of fit between the spatial scales at which ecosystem services are provided, and those at which their benefits are realized. We argue that a combination of the ecosystem services concept with a careful approach to the issue of scales will help to overcome these problems and improve the management of mangrove systems. Drawing on two case studies from Indonesia and Brazil, we illustrate the relevance of our findings for different ecosystem services.     

Equity implications of marketing ecosystem services in protected areas and rural communities: Case studies from Meso-America

This paper investigates the equity implications of marketing ecosystem services in protected areas and rural communities. We use a three-tiered equity framework to analyse four distinct efforts to commercialise watershed recharge and carbon dioxide fixation by forests in Meso-America. We show that project development and participation are strongly mediated by organisational networks, as well as existing rights of access over land and forest resources. We demonstrate that procedural fairness diverges strongly when initiatives are implemented in protected areas or in rural communities. While in the former reserve managers and intermediaries concentrate all decision-making power, initiatives working with rural communities are able to integrate more significantly service providers in management decisions. Marketing ecosystem services in protected areas contributes to reduce expenditure rates for protected area management, but also results in less equitable outcomes, as rural communities and forest resource users become excluded from receiving sustained development benefits. When ecosystem services are commercialised by rural farmers, payments do not cover opportunity costs but act as a significant incentive for participation in most cases. Ecosystem service providers also benefit from complementary project activities, such as forest management training and agricultural extension support. We argue that limited economic impact and existing inequities in decision-making and outcomes can be explained by problems of institutional design, in particular the inability of markets and payments for ecosystem services to account for context-related factors, such as property rights.     

Drivers and mechanisms of forest change in the Himalayas

Mountains are critical ecosystems that have a strong influence far beyond their topographic boundaries. More than 50 million people inhabit the Himalayas, and more than one billion people depend on the ecosystem services they provide. Anthropogenic activities have driven concurrent deforestation and regeneration in the Himalayas, and interventions to reduce forest loss and promote forest recovery require a synthetic understanding of the complex and interacting drivers of forest change. We conducted a systematic review of case studies from 1984 to 2020 (n = 137) and combined a system dynamics approach with a causal network analysis to identify, map and articulate the relationships between the drivers, actors and mechanisms of forest change across the entirety of the Himalayan mountain range. In total, the analysis revealed five proximate drivers, 12 underlying drivers, two institutional factors and five ‘other’ factors connected by a total of 221 linkages. Forest change dynamics have been dominated by widespread smallholder agriculture, extensive non-timber forest product extraction, widespread commercial and non-commercial timber extraction, and high rates of agricultural abandonment. Underlying drivers include population growth, poor agricultural productivity, international support for development projects, and successful community forest management systems. Contradictory linkages emerge from a combination of contextual factors, which can have negative impacts on conservation goals. Global processes such as shifts in governance, transnational infrastructure-development programs, economic slowdowns, labor migrations and climate change threaten to destabilize established dynamics and change forest trajectories. The underlying and proximate drivers interact through multiple pathways that can be utilized to achieve conservation goals. Based on this analysis, we highlight five thematic focus areas to curtail forest loss and promote recovery: (1) decreasing the population pressure, (2) sustainable increase of agricultural productivity, (3) strengthening of forest management institutions, (4) leveraging tourism growth and sustainable infrastructure expansion, and (5) fuel transition and establishing firewood plantations on degraded land. The broader adoption of systems thinking, and specifically a system dynamics approach and causal network analysis, will greatly enhance the rigour of policy development, help design site-specific interventions at multiple spatial scales which can respond to local and global changes, and guide deeper inquiry to enhance our understanding of driver-forest dynamics.     

Historical and future quantification of terrestrial carbon sequestration from a Greenhouse-Gas-Value perspective

Terrestrial ecosystems provide a range of important services to humans, including global and regional climate regulation. These services arise from natural ecosystem functioning as governed by drivers such as climate, atmospheric carbon dioxide mixing ratio, and land-use change. From the perspective of carbon sequestration, numerous studies have assessed trends and projections of the past and future terrestrial carbon cycle, but links to the ecosystem service concept have been hindered by the lack of appropriate quantitative service metrics. The recently introduced concept of the Greenhouse Gas Value (GHGV) accounts for the land-atmosphere exchanges of multiple greenhouse gases by taking into consideration the associated ecosystem pool sizes, annual exchange fluxes and probable effects of natural disturbance in a time-sensitive manner.We use here GHGV as an indicator for the carbon sequestration aspects of the climate regulation ecosystem service, and quantify it at global scale using the LPJ-GUESS dynamic global vegetation model. The response of ecosystem dynamics and ecosystem state variables to trends in climate, atmospheric carbon dioxide levels and land use simulated by LPJ-GUESS are used to calculate the contribution of carbon dioxide to GHGV. We evaluate global variations in GHGV over historical periods and for future scenarios (1850–2100) on a biome basis following a high and a low emission scenario.GHGV is found to vary substantially depending on the biogeochemical processes represented in LPJ-GUESS (e.g. carbon–nitrogen coupling, representation of land use). The consideration of disturbance events that occur as part of an ecosystem's natural dynamics is crucial for realistic GHGV assessments; their omission results in unrealistically high GHGV. By considering the biome-specific response to current climate and land use, and their projections for the future, we highlight the importance of all forest biomes for maintaining and increasing biogeochemical carbon sequestration. Under future climate and carbon dioxide levels following a high emission scenario GHGV values are projected to increase, especially so in tropical forests, but land-use change (e.g. deforestation) opposes this trend. The GHGV of ecosystems, especially when assessed over large areas, is an appropriate metric to assess the contribution of different greenhouse gases to climate and forms a basis for the monetary valuation of the climate regulation service ecosystems provide.     

Deforestation dynamics and drivers in different forest types in Latin America: Three decades of studies (1980–2010)

Over the last decades there have been a considerable number of deforestation studies in Latin America reporting lower rates compared with other regions; although these studies are either regional or local and do not allow the comparison of the intraregional variability present among countries or forest types. Here, we present the results obtained from a systematic review of 369 articles (published from 1990 to 2014) about deforestation rates for 17 countries and forest types (tropical lowland, tropical montane, tropical and subtropical dry, subtropical temperate and mixed, and Atlantic forests). Drivers identified as direct or indirect causes of deforestation in the literature were also analysed. With an overall annual deforestation rate of −1.14 (±0.092 SE) in the region, we compared the rates per forest type and country. The results indicate that there is a high variability of forest loss rates among countries and forest types. In general, Chile and Argentina presented the highest deforestation rates (−3.28 and −2.31 yearly average, respectively), followed by Ecuador and Paraguay (−2.19 and −1.89 yearly average, respectively). Atlantic forests (−1.62) and tropical montane forests (−1.55) presented the highest deforestation rates for the region. In particular, tropical lowland forests in Ecuador (−2.42) and tropical dry forests in Mexico (−2.88) and Argentina (−2.20) were the most affected. In most countries, the access to markets and agricultural and forest activities are the main causes of deforestation; however, the causes vary according to the forest types. Deforestation measurements focused at different scales and on different forest types will help governments to improve their reports for international initiatives, such as reducing emissions from deforestation and forest degradation (REDD+) but, more importantly, for developing local policies for the sustainable management of forests and for reducing the deforestation in Latin America.     

Divergent trends in ecosystem services under different climate-management futures in a fire-prone forest landscape

While ecosystem services and climate change are often examined independently, quantitative assessments integrating these fields are needed to inform future land management decisions. Using climate-informed state-and-transition simulations, we examined projected trends and tradeoffs for a suite of ecosystem services under four climate change scenarios and two management scenarios (active management emphasizing fuel treatments and no management other than fire suppression) in a fire-prone landscape of dry and moist mixed-conifer forests in central Oregon, USA. Focal ecosystem services included fire potential (regulating service), timber volume (provisioning service), and potential wildlife habitat (supporting service). Projections without climate change suggested active management in dry mixed-conifer forests would create more open forest structures, reduce crown fire potential, and maintain timber stocks, while in moist mixed-conifer forests, active management would reduce crown fire potential but at the expense of timber stocks. When climate change was considered, however, trends in most ecosystem services changed substantially, with large increases in wildfire area predominating broad-scale trends in outputs, regardless of management approach (e.g., strong declines in timber stocks and habitat for closed-forest wildlife species). Active management still had an influence under a changing climate, but as a moderator of the strong climate-driven trends rather than being a principal driver of ecosystem service outputs. These results suggest projections of future ecosystem services that do not consider climate change may result in unrealistic expectations of benefits.     

Mapping the diversity of regulating ecosystem services in European cities

This paper presents the first analysis of the diversity of regulating ecosystem services (ESS)—key variables for global environmental sustainability and change in an urban era—across a globally important part of the urban world, urban Europe. We map the first pan-European pattern of regulating ecosystem services in urban core areas and their associated hinterlands and discuss data against the background of each city's land-use development history and planning culture. Upon selecting more than 300 cities, we used the Urban Atlas database and a straightforward calculation method to map three regulating ecosystem services. The main results of this study show (a) a heterogeneous distribution of regulating ecosystem services across European cities, (b) considerable provisioning differences between core cities and the hinterland, (c) a grouping of European regions according to their potential for urban ecosystem service provisioning and (d) an ecosystem services supply ranking for European cities. Considerable differences in urban ecosystem services were found among northern countries, such as Sweden and Finland, which are rich in supplying ecosystem services compared to the UK and Belgium, which, similar to Spanish and Greek cities, are characteristically low in ecosystem services provision. Our results provide the first overall picture of regulating services in urban EU-Europe and serve to inform decisions on the key aspects of future European policy and strategies involving urban nature, green spaces and health.     

Buying environmental insurance: Prospects for trading of global climate-protection services

In order to alleviate the threat of global climate change, coordinated international action is needed. This cooperation should include multilateral agreements and new economic initiatives to help implement measures that will slow the accumulation of carbon dioxide in the Earth's atmosphere due to tropical deforestation and fossil-fuel use. An international market in environmental services can help to safeguard the Earth's climate and foster economic development through a North-South transfer of financial resources.We suggest international carbon-emission offsets (ICEOs) as a means by which international markets, under a policy umbrella such as a multilateral climate-protection treaty, could trade carbon-saving services. Such a market would provide a currency for rewarding actions that reduce global carbon emissions, allowing carbon emitters to seek the least expensive ways to reduce emissions. This currency would transfer cash and/or debt relief from industrialized nations to developing nations, allowing the developing nations to profit from the use of clean energy technologies and the protection, rather than depletion, of tropical forests.     

Assisted tree migration can reduce but not avert the decline of forest ecosystem services in Europe

European forests are facing multiple natural and anthropogenic pressures that are expected to become more severe in the next decades. Tree diversity is projected to decline in many areas across the continent. How this will affect the provision of forest services remains an open question, whose answer depends, among others, on the practical and theoretical challenges of incorporating assisted migration into climate adaptation strategies. Here, we tackle the issue by combining a large dataset of tree species occurrences, future climatic projections, and data on tree functional traits and tree-specific forest services into a novel modelling framework. We estimate that, by the end of the century and under a natural dispersal scenario, the provision of forest services would decrease on average by 15% in Europe (for RCP 4.5; 23% for RCP 8.5), and up to 52% (70% for RCP 8.5) in the Mediterranean. To explore if and how management could reduce the projected losses, we simulated a suite of alternative assisted migration strategies aimed at identifying, for each locality, the tree species communities offering the best compromise in terms of resilience to climate change and delivery of specific combinations of ecosystem services. Such strategies could reduce losses of services by 10% (15%) on average in Europe, and even increase service availability in the Alpine and Boreal regions but not in the Mediterranean, where losses will remain as high as 33% (54% for RCP 8.5). Our findings highlight how science-driven management strategies could be vital to reduce an otherwise dramatic, European-wide decline of forest services. Our results are qualitatively robust to different assumptions on future carbon emissions and related climate trajectories. That is, our simulated assisted migration strategies identify similar tree species communities under different pathways (RCP 4.5 vs RCP 8.5). This makes our approach a powerful tool for forest management, as it generates advice that is valid regardless of whether, and to what extent, human society will steer away from business-as-usual emission trajectories.     

The Congo Basin forests in a changing climate: Policy discourses on adaptation and mitigation (REDD+)

This paper discusses the discourses on climate change adaptation and mitigation that are currently at the forefront in the Congo Basin. On mitigation, the forests have enormous opportunities to contribute to the reducing emissions from deforestation and forest degradation (REDD+) mechanism. But the forest itself and its multiple dependent societies and sectors need to adapt to potential climate risks. Hence, actors are debating the design of climate change policy in the forest sector. Theoretically, we combine the agency-focus of frame analysis and discourse theory to analyze how different agents hold frames on climate change adaptation and mitigation policies in the region. This paper draws upon interviews with 103 different actors from government, international organizations, non-governmental organizations, research institutions and private sector in three countries: Cameroon, Central African Republic (CAR) and Democratic Republic of Congo (DRC). Three discourses were found on policy response to climate change in the forest sector: mitigation policy only, separated policy on adaptation and mitigation, and an integrated policy on adaptation and mitigation. The various frames articulated around each discourse by the coalitions include elements of: costs and benefits, scale of operation, effectiveness, financial resources and implementation mechanisms. Overall, the mitigation discourse, through its mix of actors, resources and interests seems to be stronger than the adaptation discourse. The paper finally outlines a number of implications of the discourses for policy design.     

A social contract with the ancestors—Culture and ecosystem services in southern Madagascar

We investigate the role of culture in sustaining essential ecosystem services in the arid and erratic climate of an agropastoral landscape in southern Madagascar. Our fieldwork and interviews in Ambovombe subprefecture in Androy addressed land use, agropastoralism, livelihood, institutions and their moral basis. Our analysis points to the interdependence of cultural practices and ecosystem services: sacred forests, crop pollination, subsistence farming, cattle economy and societal transition and purification rituals. We posit a social-ancestral contract that works as a moral attractor structuring and sustaining the agropastoral ecosystem services system. The contract between living and nonliving clan members underpins the cultural practices and rituals that regulate the vulnerable agropastoral system. We conclude that the well-being values of the inhabitants of the south of Madagascar depend upon moralities that lend legitimacy and stability to the management of the social–ecological processes that precondition ecosystem services production. Neither ecosystem nor culture delivers ecosystem services to society. Ecosystem services are generated by an interdependent social–ecological system in which knowledge, practice, and beliefs coevolve: culture is a key factor in their generation and persistence. The study suggests these are significant interdependences to consider in dynamic analyses of ecosystem service production.     

Enhancing the sustainability of commodity supply chains in tropical forest and agricultural landscapes

The rapid expansion of the production of agricultural commodities such as beef, cocoa, palm oil, rubber and soybean is associated with high rates of deforestation in tropical forest landscapes. Many state, civil society and market sector actors are engaged in developing and implementing innovative interventions that aim to enhance the sustainability of commodity supply chains by affecting where and how agricultural production occurs, particularly in relation to forests. These interventions – in the form of novel or moderated institutions and policies, incentives, or information and technology – can influence producers directly or achieve their impacts indirectly by influencing consumer, retailer and processor decisions. However, the evidence base for assessing the impacts of these interventions in reducing the negative impacts of commodity agriculture production in tropical forest landscapes remains limited, and there has been little comparative analysis across commodities, cases, and countries. Further, there is little consensus of the governance mechanisms and institutional arrangements that best support such interventions. We develop a framework for analyzing commodity supply chain interventions by different actors across multiple contexts. The framework can be used to comparatively analyze interventions and their impacts on commodity production with respect to the spatial and temporal scales over which they operate, the groups of supply chain actors they affect, and the combinations of mechanisms upon which they depend. We find that the roles of actors in influencing agricultural production depends on their position and influence within the supply chain; that complementary institutions, incentives and information are often combined; and that multi-stakeholder collaborations between different groups of actors are common. We discuss how the framework can be used to characterize different interventions using a common language and structure, to aid planning and analysis of interventions, and to facilitate the evaluation of interventions with respect to their structure and outcomes. Studying the collective experience of multiple interventions across commodities and spatial contexts is necessary to generate more systematic understandings of the impacts of commodity supply chain interventions in forest-agriculture landscapes.     

Climate change vulnerability of sustainable forest management in the Eastern Alps

Considering climatic uncertainties in management planning is a prerequisite for sustainable forest management (SFM). The aim of the study was to evaluate climate change vulnerability of the current SFM strategy for commercial forests managed by the Austrian Federal Forests. To that end vulnerability indicators were defined in a stakeholder process (selected indicators were productivity, timber and carbon stocks, biodiversity, disturbances, a tree species’ position in fundamental niche space, silvicultural flexibility and cost intensity) and their performance under climate change scenarios assessed with an ecosystem model. Multi criteria analysis techniques were employed in a partial aggregation of indicators to locate forest stands on a vulnerability surface. Results revealed high vulnerability particularly in the second half of the twenty-first century, where 39.6% of the 164.550 ha study area were assessed highly vulnerable to climate change, indicating a strong decline in the functions and services represented by the indicator system. Water-limited sites on calcareous bedrock were most negatively affected whereas assessment units at higher altitudes responded predominately positive to climate warming. The presented approach, transparently integrating multiple management objectives and allowing a quantitative comparison of vulnerabilities between sites and management strategies, contributes to the development of operational and efficient climate change adaptation measures in forest management.     

Future impacts of drivers of change on wetland ecosystem services in Colombia

Wetlands are among the most valuable ecosystems in the world due to their delivery of ecosystem services (ES), but they are particularly vulnerable to drivers of land-use change. However, little is known about how different wetlands respond to drivers of land-use change and how that impacts their delivery of ES. After extreme floods hit Colombia in 2010–2011, negative impacts from these storms heightened the interest of Colombian policy-makers in understanding and recognizing the importance of wetlands. Here, we present a map with 19 wetland types for Colombia and assess the ES that these wetlands deliver and how those ES are impacted by drivers of land-use change. We based our spatial analysis on the Corine Land Cover data for Colombia and combined that with spatial indices derived from knowledgeable experts using the matrix approach and participatory mapping (PGIS). The most vulnerable wetland types identified were floodplain forests, riparian wetlands, freshwater lakes and rivers. The region of Magdalena-Cauca has been identified as the most vulnerable to the impacts of land-use change, until 2025. We discuss our results in light of the current Colombian policy-debate which concerns the designation of wetlands as strategic ecosystems. This designation implies necessary restrictions or prohibition of harmful activities in wetlands, principally mining and industrial agriculture.     

Biodiversity mediates relationships between anthropogenic drivers and ecosystem services across global mountain,island and delta systems

Global change increasingly threatens nature, endangering the ecosystem services human wellbeing depends upon. Biodiversity potentially mediates these impacts by providing resilience to ecosystems. While biodiversity has been linked to resilience and ecosystem service supply on smaller scales, we lack understanding of whether mediating interactions between biodiversity and anthropogenic drivers are global and ubiquitous, and how they might differ between systems. Here, we examine the potential for biodiversity to mediate anthropogenic driver-ecosystem service relationships using global datasets across three distinct systems: mountains, islands and deltas. We found that driver-ecosystem service relationships were stronger where biodiversity was more intact, and weaker at higher species richness, reflecting the negative correlation between intactness and richness. Mediation was most common in mountains, then islands, then deltas; reducing with anthropogenic impact. Such patterns were found across provisioning and regulating ecosystem services, and occurred most commonly with climate change and built infrastructure. Further, we investigated the contribution of biodiversity and abiotic and anthropogenic drivers to ecosystem services. Ecosystem service supply was associated with abiotic and anthropogenic drivers alongside biodiversity, but all drivers were important to different ecosystem services. Our results empirically show the importance of accounting for the different roles that biodiversity plays in mediating human relationships with nature, and reinforce the importance of maintaining intact biodiversity in ecosystem functioning.     

Consequences of actor level livelihood heterogeneity for additionality in a tropical forest payment for environmental services programme with an undifferentiated reward structure

Primary tropical forests provide crucial environmental services, including carbon storage and hydrological regulation. Options for promoting forest conservation include payments for environmental services (PES) programmes that provide financial incentives to local actors, in exchange for reduced forest clearance. The success of voluntary PES (defined in terms of avoided primary forest conversion) is contingent upon behavioural changes in enrolled actors. As both the degree of enrolment and likelihood of sustained behavioural change depend upon how PES compensation structures interact with existing actor economies, local heterogeneity in livelihood strategies may play a strong role in the ultimate success of PES programmes, particularly when compensation is not differentiated with respect to opportunity costs. We examined the influence of livelihood heterogeneity on the potential success of a deforestation-reduction PES with an undifferentiated reward structure. We collected socioeconomic and demographic data at the household and community levels across two large Amazonian extractive reserves where a spatially extensive PES programme (Bolsa Floresta) operates. We show that demographic and socioeconomic status varies widely across households and communities, and found that both households and communities that are most and least likely to convert primary forest receive similar financial incentives. Those households most engaged in manioc agriculture (the primary driver of local primary forest conversion) both benefitted from the highest annual incomes and incurred the greatest opportunity costs. We show that avoided primary forest conversion could be greatly increased with differentiated payment structures adjusted for local differences in opportunity costs and livelihood strategies, and present two metrics that could help to achieve that goal.     

Cross-site analysis of perceived ecosystem service benefits in multifunctional landscapes

Rural development policies in many Organization for Economic Co-operation and Development (OECD) member countries promote sustainable landscape management with the intention of providing multiple ecosystem services (ES). Yet, it remains unclear which ES benefits are perceived in different landscapes and by different people. We present an assessment of ES benefits perceived and mapped by residents (n = 2,301) across 13 multifunctional (deep rural to peri-urban) landscapes in Europe. We identify the most intensively perceived ES benefits, their spatial patterns, and the respondent and landscape characteristics that determine ES benefit perception. We find outdoor recreation, aesthetic values and social interactions are the key ES benefits at local scales. Settlement areas are ES benefit hotspots but many benefits are also related to forests, waters and mosaic landscapes. We find some ES benefits (e.g. culture and heritage values) are spatially clustered, while many others (e.g. aesthetic values) are dispersed. ES benefit perception is linked to people’s relationship with and accessibility to a landscape. Our study discusses how a local perspective can contribute to the development of contextualized and socially acceptable policies for sustainable ES management. We also address conceptual confusion in ES framework and present argumentation regarding the links from services to benefits, and from benefits to different types of values.     

Potential Carbon Flux from Timber Harvests and Management in the Context of a Global Timber Market

This paper presents carbon flux estimates arising from the effect of increasing demand on harvests and management of industrial forests in a global timber market. Results are presented for specific regions and the globe. Harvests and management of forests are predicted to store an additional 184 Tg (1 Tg = 10¹² grams) of carbon per year in forests and wood products over the next 50 years, with a range of 108 to 251 Tg per year. Although harvests in natural boreal and tropical forest regions will cause carbon releases, new plantation establishment in subtropical emerging regions more than offsets these losses. Unlike many existing studies, these results suggest that harvests and management of North American forests will lead to carbon emissions from that region over the next 50 years. The results are quantitatively sensitive to the assumed growth in demand although the results are qualitatively similar in the sensitivity analysis.     

The role of soybean production as an underlying driver of deforestation in the South American Chaco

South America’s tropical dry forests and savannas are under increasing pressure from agricultural expansion. Cattle ranching and soybean production both drive these forest losses, but their relative importance remains unclear. Also unclear is how soybean expansion elsewhere affects deforestation via pushing cattle ranching to deforestation frontiers. To assess these questions, we focused on the Chaco, a 110 million ha ecoregion extending into Argentina, Bolivia, and Paraguay, with about 8 million ha of deforestation in 2000–2012. We used panel regressions at the district level to quantify the role of soybean expansion in driving these forest losses using a wide range of environmental and socio-economic control variables. Our models suggest that soybean production was a direct driver of deforestation in the Argentine Chaco only (0.08 ha new soybean area per ha forest lost), whereas cattle ranching was significantly associated with deforestation in all three countries (0.02 additional cattle per hectare forest loss). However, our models also suggested Argentine soybean cultivation may indirectly be linked to deforestation in the Bolivian and Paraguayan Chaco. We furthermore found substantial time-delayed effects in the relationship of soybean expansion in Argentina and Paraguay (i.e., soybean expansion in one year resulted in deforestation several years later) and deforestation in the Chaco, further suggesting that possible displacement effects within and between Chaco countries may at least partly drive forest loss. Altogether, our study showed that deforestation in the Chaco appears to be mainly driven by the globally surging demand for soybean, although regionally other proximate drivers are sometimes important. Steering agricultural production in the Chaco and other tropical dry forests onto sustainable pathways will thus require policies that consider these scale effects and that account for the regional variation in deforestation drivers within and across countries.     

How the future of the global forest sink depends on timber demand,forest management,and carbon policies

Deforestation has contributed significantly to net greenhouse gas emissions, but slowing deforestation, regrowing forests and other ecosystem processes have made forests a net sink. Deforestation will still influence future carbon fluxes, but the role of forest growth through aging, management, and other silvicultural inputs on future carbon fluxes are critically important but not always recognized by bookkeeping and integrated assessment models. When projecting the future, it is vital to capture how management processes affect carbon storage in ecosystems and wood products. This study uses multiple global forest sector models to project forest carbon impacts across 81 shared socioeconomic (SSP) and climate mitigation pathway scenarios. We illustrate the importance of modeling management decisions in existing forests in response to changing demands for land resources, wood products and carbon. Although the models vary in key attributes, there is general agreement across a majority of scenarios that the global forest sector could remain a carbon sink in the future, sequestering 1.2–5.8 GtCO2e/yr over the next century. Carbon fluxes in the baseline scenarios that exclude climate mitigation policy ranged from −0.8 to 4.9 GtCO2e/yr, highlighting the strong influence of SSPs on forest sector model estimates. Improved forest management can jointly increase carbon stocks and harvests without expanding forest area, suggesting that carbon fluxes from managed forests systems deserve more careful consideration by the climate policy community.