IBFRA 2021: Sessions description

Chair, co-chair: Xanthe Walker¹, Michelle Mack¹

¹Northern Arizona University, Flagstaff Arizona, USA

Wildfire has shaped forests and even tundra of the Arctic region for much of the Holocene, but recent warming is intensifying fire activity. In boreal forests of North America, the current rate of burning exceeds that of the last half of the 20^th century and may even exceed rates of the last five millennia. Boreal fires are burning at higher intensities and more deeply into organic soils, releasing older carbon (C) to the atmosphere. Even regions that have rarely burned historically are vulnerable to crossing climate thresholds likely to increase fire activity. Because these forests and cold soils store approximately 30% of global terrestrial C in a pool twice the size of the atmospheric C pool, net C release from increased fire activity could be a global climate tipping point that will accelerate human-caused climate warming. The ecological process of fire self-limitation could slow these climate-driven increases in fire activity if it is resilient to climate warming in the Boreal biome. Fire self-limitation hinges on the premise that burning consumes fuels, reducing the risk of subsequent ignitions and fire spread until fuels reaccumulate to levels that can once again sustain fire. This is thought to be a system-level, self-regulatory process that drives a negative, stabilizing feedback between fire and vegetation in all natural fire regimes on Earth. There have been calls for policies that explicitly use this concept to address increasing fire risk in the North. Whether this internal negative feedback is large enough in magnitude to mitigate climate warming effects on fire is uncertain. Fire-vegetation interactions in boreal forest can suppress, have no impact, or more rarely, accelerate burning. If this negative feedback between fire and vegetation is large in magnitude and resilient to future climate, it could mitigate fire activity and corresponding impacts on climate and people. If the feedback proves fragile and erodes with future climate, it will accelerate warming, stress fire-management resources, and threaten people and property. In this session, speakers will weigh in evidence for and against fire self-limitation in the boreal biome. Presentations will include field, modeling and remote sensing studies, analysis of fire management policy and fire risk, and quantitative and conceptual synthesis. We would like to use this session as a mechanism for organizing a working group on this topic.

Chair, co-chairs: Tatiana Shestakova¹, Brendan Rogers¹

¹Woodwell Climate Research Center, Woods Hole MA, USA

Undisturbed boreal forests, 'primary forests', or those with high ecosystem or ecological 'integrity', provide a variety of ecosystem services including carbon storage, regulating climate and hydrology, air quality, and fostering biodiversity. They are also critically important for the livelihood of local communities, providing recreation and tourism opportunities as well as cultural and spiritual values. The boreal biome has the largest remaining undisturbed forest cover globally; however, it is in decline due to widespread forest conversion and degradation. To ensure adequate protection and management of boreal forests, we require better spatial quantification of forest integrity, valuation of ecosystem services, and optimization of forest management for multiple stakeholders. In this session we invite contributions that (i) provide metrics and frameworks to quantify boreal forest integrity and ecosystem services; (ii) map the spatial distribution of forest integrity, primary forests, or ecosystem services; and (iii) explore the impact of harvest, land use change, fires, and other types of forest management or disturbance on boreal forest integrity and ecosystem services. We also invite submissions encouraging an open discussion on management options and policy recommendations related to boreal forest integrity and primary forests.

Chair, co-chair(s): Dmitry Schepaschenko ^1,2, Sergey Bartalev ³, Christiane Schmullius ⁴

¹ Ecosystem Services and Management Program, International Institute for Applied Systems Analysis (IIASA), Austria; ² Center on Forest Ecology and Productivity, Russian Academy of Sciences, Moscow, Russia; ³ Russian Space Research Institute, Russian Academy of Sciences, Moscow, Russia; ⁴ Friedrich-Schiller University, Jena, Germany

Remote sensing technologies provide timely and consistent information about forest cover and forest properties, as well as their dynamics. A forest carbon budget estimation require data on land cover and forest characteristics (growing stock volume, species composition, age, site-index) along with data on natural (fires, diseases and pests, windstorm, droughts) and anthropogenic (felling, pollution) disturbances causing forest degradation and deforestation, as well as information on subsequent reforestation processes are also vital. The remote sensing methods can provide significant part of this information. The multi-year time series of remote sensing data and derived products allow modelling the forest dynamics for better understanding of ongoing and projection of future changes and for improved carbon budget estimation.

Our session will focus on success stories in following topics:

- Land cover and forest cover mapping

- Estimation of forest properties (tree species, age, growing stock and biomass, etc.)

- Disturbances monitoring (wildfire, insect and diseases outbreaks, logging)

- Long-term forest dynamics analysis using multi-year data time series

- Linking ground measurements with remote sensing observations

- Integration of remote sensing data with forest dynamics models

- Forest carbon assessment using remote sensing data and modeling

Chair, co-chairs: Abhishek Chatterjee^1,2, Brendan Rogers³, Nicholas Parazoo⁴, Scott Goetz⁵

¹ NASA Goddard Space Flight Center, Greenbelt, MD; ² Universities Space Research Association, Columbia, MD; ³ Woods Hole Research Center, Falmouth, MA; ⁴ Jet Propulsion Laboratory, Pasadena, CA; ⁵ Northern Arizona University, Flagstaff, AZ

Boreal ecosystems represent one of the largest reservoirs of terrestrial carbon, most of it contained in organic soils, and play a key role in the global carbon budget. Boreal forests and their carbon stocks are highly sensitive to climate change and associated disturbances. Changes in boreal forest carbon stocks may significantly alter the terrestrial ecosystem carbon balance and generate a potentially large but uncertain positive feedback to climate change. This session focuses on studies (modeling, field-based, or experimental) that investigate how carbon stocks and fluxes in boreal ecosystems (forests and peatlands) has changed, is changing, or will change in response to changes in climate, atmospheric CO₂, and disturbance regimes such as wildfire. We invite contributions focused on: 1) quantifying the historical, current, and future carbon balance of boreal forests, component fluxes and storages (aboveground and belowground carbon stocks) using airborne and satellite remote sensing datasets, machine learning and/or data assimilation techniques; 2) analyzing the effects of nutrients, disturbances and site conditions on boreal carbon stocks; 3) understanding the impact of fires on boreal carbon dynamics and their evolution in a warming climate; 4) use of innovative approaches such as multi-spectral (e.g., NDVI) and hyperspectral (e.g., SIF) remote sensing, active and stable isotopes, and novel atmospheric tracers (e.g., CO, carbonyl sulfide) to better understand ecosystem uptake and provide insights into process-based model formulations.

Chair, co-chairs: Anatoly Shvidenko¹, Sylvie Gauthier², Natalia Lukina³, Yude Pan⁴, Dmitry Schepaschenko¹

¹ Ecosystem Services and Management Program, International Institute for Applied Systems Analysis (IIASA), Austria; ² Natural Resource Canada, Quebec, Canada; ³ Centre For Problems Of Ecology And Productivity Of Forests, Russian Academy of Sciences, Moscow, Russia; ⁴ Northern Research Station, USDA Forest Service, Durham, New Hampshire, USA

Recent studies have consistently confirmed the growing role of boreal forests in the global carbon cycle and, therefore, in the functioning of feedback to the climate system of the Earth. However, the forest carbon results of national and circumboreal assessments are diverse and different greatly. Published studies that attempted to adequately estimate uncertainties are often oversimplifying and unable to provide unbiased estimates for complex processes in boreal forest ecosystems under rapid environmental changes. Differences in national estimates of carbon sink in forest ecosystems of the boreal zone may reach two to three times among particularly those of national reports to the IPCC Secretariat and majority of the research results in individual boreal countries. To deal with this fuzzy nature of boreal carbon cycle processes, we need to have in-depth system analyses and predetermine specific requirements for evaluating extant studies and interpreting the results.

The session is expected to discuss the following scientific issues:

1. Methodology for studying the carbon cycle of forest ecosystems of the boreal zone as a fuzzy (underspecified) system, including methods, initial data, inventories, models, and uncertainty analysis.

2. The influence of terrestrial ecosystems of the boreal zone on the global carbon budget for the period of the climate warming (1975-2018) based on regional, national and circumpolar studies and results plus identifying the role of climatic trends and extremes, fertilization effect of elevated atmospheric carbon dioxide concentration (eCO₂), nitrogen deposition and disturbances.

3. Projections of the carbon budget of boreal forest ecosystems for 2020 - 2100 - what can we learn today about the future of ecosystem services of boreal forests? How significant is the management role for tending transitional boreal forests to sustainable, risk resilient forests? To what level and extent of environmental changes and to which vulnerable spots in boreal zones, would it likely be triggered the tipping element in boreal forest ecosystems?

Chair and co-chair: Roger Ruess¹ , Knutt Kielland¹

¹ Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, USA

Climate- and disturbance-driven changes in trophic dynamics affect the population dynamics of plants and animals and ecosystem function by altering the abundance of key plant species. In turn, trophic dynamics are being influenced by phenological responses of native and invasive plants to climate change, particularly during the shoulder seasons. Throughout interior Alaska, changing disturbance regimes are influencing the population dynamics and movement patterns of vertebrate herbivores and their predators, and plant-browser interactions are shaping regional vegetation responses to environmental change. Long-term impacts of insect herbivores are less well understood. In addition to direct effects on plant performance, which can be substantial during outbreaks, insect herbivores may indirectly affect patterns of browsing by mammals by reducing plant quality and slowing growth, leading to underappreciated interactive effects. Changing disturbance regimes are also affecting the complex interactions among drought, invertebrate herbivores and plant pathogen outbreaks.

Chair, co-chairs: Pascal Bodmer¹, David E. Butman², Joan Pere Casas-Ruiz¹, Paul del Giorgio¹, Daniel Hayes³, Rob Striegl⁴

¹Université du Québec à Montréal, Canada; ²University of Washington, Seattle WA, USA; ³University of Maine, Orono ME, USA; ⁴USGS, Boulder CO, USA

The continental landscape is made up of a heterogeneous mosaic of ecosystems that may include various types of forests, grasslands, wetlands and inland waters, each having their own ecosystem properties and processes. This complexity has led to conceptual compartmentalization in regional and continental models and carbon budgets, where each ecosystem is treated independently of the others. In nature, however, all these ecosystems are interconnected and exchange carbon and other materials with each other. Lateral carbon exchanges among ecosystems, e.g. through surface and subsurface water flow, are often overlooked in landscape carbon accounting frameworks. However they can have strong impacts on the assessment of above and below ground change of forest and wetland carbon stocks as well as on estimates of the land-atmosphere exchange of carbon. These exchanges are also key to the biogeochemical functioning of the receiving inland waters. In this session, we welcome contributions that (i) integrate carbon dynamics of aquatic, wetland and terrestrial ecosystems, (ii) work at the interface of aquatic and terrestrial ecosystems (e.g. riparian zones and saturated soils), or (iii) measure lateral exchanges between different landscape components. These contributions can be either conceptual, experimental, or in the field at local to regional scales.

Chair: Hongyan Liu¹

¹Pekin University, college of urban and environment sciences, Beijing, China

Boreal forest distribution is closely associated with permafrost. Climate warming has accelerated the melting of permafrost and deepening of its active layer, leading to changing soil and water conditions for the growth of boreal forest on it. How the boreal forest responds to warming-induced permafrost degradation, including but not limited to changes in tree growth, species composition, and succession, remains big challenges. We sincerely invite the state-of-art works on climate change, soil, and ecology of boreal forest related with permafrost degradation, in order to promote our understanding of patterns and processes of the boreal forest under warming-induced permafrost degradation.

Chair, co-chairs: Logan Berner¹, Adrianna Foster¹, Brendan Rogers²

¹Northern Arizona University, Flagstaff Arizona, USA, ²Woods Hole Research Center, Woods Hole MA, USA

Climate exerts a strong influence on forest productivity and demographic processes in the boreal biome, thus rendering the boreal forest sensitive to climatic change. There is mounting observational evidence that rising temperatures and changes in water availability are impacting the boreal forest. This session will explore observations of climate impacts on boreal forest productivity and demographic processes during the 20^th and early 21^st centuries. We encourage submissions that assess climate impacts on boreal forest dynamics using satellite remote sensing, tree-rings, forest inventories, and other observational time-series approaches. We especially encourage submissions focused on (1) treeline dynamics along the margins of the boreal forest; (2) impacts of drought and heat stress; and (3) impacts of changing disturbance intensity, frequency, and severity. The sessions will involve a series of short talks followed by a panel discussion.

Chair, co-chairs: Adrianna Foster¹, Logan Berner¹, Brendan Rogers²

¹Northern Arizona University, Flagstaff Arizona, USA, ²Woods Hole Research Center, Woods Hole MA, USA

Format: Presentations followed by a panel discussion

The boreal forest is currently undergoing rapid changes in climate and disturbance regimes, driving consequent changes in productivity, structure, composition, and overall vegetation dynamics. The many interacting and sometimes counteracting drivers of vegetation dynamics within the boreal zone (e.g. wildfire, soils, climate, and vegetation feedbacks) make predicting future boreal forest conditions a complex problem. Various modeling techniques at different temporal and spatial scales may be used to predict potential future boreal forest trajectories, however, there is still uncertainty in these projections. This session will explore predictions of future boreal forest conditions and trajectories, with an emphasis on mechanistic simulation modelling. We encourage abstracts that focus on simulations of future boreal forest productivity, composition, and dynamics, with an emphasis on 1) how changes in climate and disturbances will interact with vegetation dynamics and demographics; 2) potential negative and positive feedbacks between vegetation and vegetation drivers (e.g. climate, wildfire, etc.) and methods of simulating these feedbacks; and 3) sources of uncertainty in future predictions. A panel discussion on all of these topics will follow the talks.

Chair and co-chair: Vincent Roy¹ , Alexis Achim²

¹ Canadian Forest Service, Toronto, Canada, ²Laval University, Québec, Canada

It is increasingly clear that growth and yield (G&Y) models currently used in forest management do not adequately account for the impact of future climatic changes on growth rate, mortality and recruitment, which jeopardize the sustainability of forest management in the boreal forest over the next century. Research has shown that the extent of change will vary, depending not only on species and region, but also on the data used to examine the problem and the analytical approach employed. Also, remote sensing based enhanced forest inventories offer an opportunity to improve G&Y models. This session will focus on next generation growth models that will contribute to anticipate future changes and improve assessments of forest sustainability in multiple areas of interest. A facilitated discussion at the end of the session will look at opportunities to increase circumboreal collaboration to undertake climate sensitive growth modelling.

Chair: Aapo Rautiainen

¹ Natural Resources Institute Finland, Bioeconomy and Environment, Helsinki, Finland

This session focuses on the economics of forestry in a changing climate. Both adaptation and mitigation are considered. The circumboreal region is warming at a faster pace than the world on average. Forestry needs to adapt. How can we best manage our forests in a changing climate? Besides adaptation, forests can also help mitigate climate change. How can we best balance mitigation with other forest management goals?

Chair: Aapo Rautiainen¹

¹ Natural Resources Institute Finland, Bioeconomy and Environment, Helsinki, Finland

Forests provide many valuable ecosystem services. Some of these services are interdependent; the provision of one may strengthen or weaken that of another. This session focuses on the optimization of forest management for two or more ecosystem services at once. Studies on any relevant combination are welcome.

Chair: Karin Hjelm¹, Brad Pinno², Nelson Thiffault³

¹ Swedish University of Agricultural Sciences, ² University of Alberta, Canada, ³Canadian Forest Service, Canada

Format: Presentations followed by a panel discussion

Spruce forests (dominated by members of the genus Picea) are a common and defining feature of the circumboreal forest. These forests are important ecologically, supporting a broad range of ecosystem services, and economically as the basis of many timber industries. The management intensity of these forests varies greatly, from little human intervention in remote natural forests, to heavily managed plantation forests in more accessible and productive areas. However, spruce forests across the boreal region are becoming increasingly vulnerable to changes in fire regimes, drought and pest outbreaks along with human activities. In some regions range contractions are predicted without changes in management. The specific issues and challenges associated with managing spruce forests vary greatly across their range. For this session, we invite presentations on the linkages between spruce ecology and management. We will close the session with a facilitated discussion of common themes and issues, such as research gaps and future challenges in management, with a goal of developing a common framework for knowledge exchange and collaborative research.

Chair: D.J.H. Sleep¹,F. Kraxner², M. Whelan³

¹ Conservation Science and Strategy, the Sustainable Forestry Initiative (SFI®), ² International Institute for Applied Systems Analysis (IIASA) , ³ Canadian Forest Service, Natural Resources Canada

Format: Presentations followed by a panel discussion

The boreal biome has always been critical for providing many global ecological, societal and economic services. The demand on these services are increasing and public policy makers need to respond with answers such as Nature Based Solutions and other policy tools. Now more than ever, policy makers are looking to science to answer some of the most urgent questions. But are policy makers asking the right questions? Are researchers working on the right issues? How do we ensure that we collectively develop science and policy statements that provide a basis for sound decision-making?. This panel will explore a recent approach involving IBFRA, a number of boreal governments, and a new science-policy forum devoted to the boreal.